CN111442931B

CN111442931B - Supercritical fuel combustion test equipment

Info

Publication number: CN111442931B
Application number: CN202010347116.8A
Authority: CN
Inventors: 康会峰; 宣佳林; 刘志宾; 徐胜利; 边振君; 曹睿智; 杨宏宇; 王纯龙
Original assignee: North China Institute of Aerospace Engineering
Current assignee: North China Institute of Aerospace Engineering
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2021-10-19
Anticipated expiration: 2040-04-28
Also published as: CN111442931A

Abstract

The invention discloses a fuel supercritical combustion test device which comprises a hydraulic pushing device, a nylon plug, a heavy piston installation section, a heavy piston, a compression pipe supporting device, a compression pipe thrust device, a heavy piston stopping device, an experiment cabin supporting device, a steel rail and a high-pressure source, wherein the nylon plug and the heavy piston are respectively arranged in the left side and the middle pipe of the heavy piston installation section, the lower side of the heavy piston installation section is communicated with the high-pressure source below through a ball valve, the right side of the heavy piston installation section is connected with the compression pipe, the compression pipe is supported through the compression pipe supporting device, the compression pipe thrust device is arranged at one third of the compression pipe and is positioned by a thrust ring, and the heavy piston stopping device is connected with the experiment cabin. The invention improves the stopping efficiency of the heavy piston and the safety in the stopping process, reduces the high stress strain at the moment of contact between the heavy piston and the stopping block, prolongs the service life of the heavy piston and the stopping block, and simultaneously improves the stability of the temperature and the pressure of a test chamber in the test process.

Description

Supercritical fuel combustion test equipment

Technical Field

The invention relates to the technical field of test equipment, in particular to fuel supercritical combustion test equipment.

Background

Evaporation and combustion are fundamental problems in rocket engine operation, the combustion characteristics affect the performance of rocket engines, the fuel evaporation and combustion rate under supercritical conditions is greatly increased compared to subcritical conditions, and liquid fuels exhibit similar characteristics to gaseous fuels. Thus, there is a substantial difference between subcritical and supercritical combustion. Generally, the pressure and temperature conditions of a rocket engine combustion chamber exist under which supercritical combustion of fuel occurs, and therefore supercritical combustion is a typical combustion problem of a rocket engine.

Both the shock tube and the heavy piston driver are experimental devices capable of generating uniform high-temperature high-pressure gas, but the conventional shock tube is simple to operate and wide in state parameter variation range, but the experimental time is short, and meanwhile, the shock tube is greatly influenced by the flow in the shock tube. It is therefore contemplated to develop a heavy piston actuator that prevents the rebound of the heavy piston to create and maintain a high temperature and pressure environment for a longer period of time, using a high speed camera to capture the behavior of a single drop of fuel in a supercritical state.

Disclosure of Invention

The invention aims to provide fuel supercritical combustion test equipment, which is ingenious in structural design, is provided with a heavy piston stopping device and an adjusting cushion block for changing a compression ratio, solves the problems of short test time and constant compression ratio of the conventional test device, can generate and maintain a high-temperature and high-pressure environment for a long time, effectively reduces the damage of high-speed hard impact of a heavy piston in the equipment to the test equipment, and prolongs the service life of the equipment.

In order to solve the technical problems, the invention adopts the following technical scheme:

the invention relates to a fuel supercritical combustion test device which comprises a hydraulic pushing device, a nylon plug, a heavy piston installation section, a compression pipe supporting device, a compression pipe thrust device, a heavy piston check device, a test cabin supporting device, a steel rail, a high-pressure source, a ball valve and a heavy piston, wherein the hydraulic pushing device, the nylon plug, the heavy piston installation section, the heavy piston, the compression pipe, the heavy piston check device and the test cabin are sequentially arranged to form a test line, the nylon plug is arranged at one side of the heavy piston installation section, which is close to the hydraulic pushing device, the bottom of the heavy piston installation section is communicated with the high-pressure source through the ball valve, the compression pipe is supported through two compression pipe supporting devices, the compression pipe supporting devices can be slidably placed on the steel rail, and the compression pipe thrust device is installed at a thrust ring part of the compression pipe, the high-pressure source is arranged on a bottom bracket of the compression tube supporting device, and the heavy piston stopping device is connected with the experiment cabin and supported by the experiment cabin supporting device.

Furthermore, the hydraulic pushing device comprises a rear bracket seat, a rear support, an oil cylinder auxiliary support, a positioning pin, a rotating shaft fixing cover, a bearing plate, a fixing screw A, a deep groove ball bearing, a piston, an oil cylinder seat and a bolt group A, a round bracket is arranged on the rear bracket seat, the rotating end at the bottom of the rear support passes through a deep groove ball bearing and is connected in the round bracket, the corner of the rear support is provided with a positioning pin which penetrates through the rear support and is embedded and connected in an anti-rotation hole on the top surface of the rear support seat, a rotating shaft fixing cover is arranged on the bottom surface of the rotating end of the rear support and is fixed on the rear support through a screw, the oil cylinder and the oil cylinder seat are connected to the rear support through a bolt group A, the lower part of the front end of the oil cylinder is lapped on the auxiliary support of the oil cylinder, and the head of a piston in the oil cylinder is in interference fit connection with a bearing plate; the oil cylinder auxiliary support is fixed on the top plate of the rear support seat through the fixing screw A, a piston is arranged in the oil cylinder, and the end part of the piston is connected with the bearing plate; the rotary shaft fixing cover is connected to the bottom surface of the rear support through a bolt, and a through hole fixedly connected with the ground is formed in the bottom plate of the rear support seat.

Still further, the heavy piston mounting section comprises a T-shaped pipe sleeve, a middle pipe, a connecting flange, a bolt group B and corresponding fittings, wherein the T-shaped pipe sleeve and the connecting flange are fastened through the bolt group B and sealed through a fourth O-shaped ring; the middle pipe penetrates through a center hole of the T-shaped pipe sleeve and an inner hole of the connecting flange, a second O-shaped ring is arranged on a contact surface of the connecting flange and the middle pipe, a grid section is arranged in the middle of the middle pipe, air communication between the middle pipe and the T-shaped pipe sleeve is achieved, the middle pipe is provided with a first air inlet small hole for filling percussion gas and a second air inlet small hole for vacuumizing, inflating and washing, a positioning boss is arranged at the right end of the middle pipe, the connecting flange is mounted on the positioning boss, an air inlet and an air outlet at the bottom of the T-shaped pipe sleeve are connected with the ball valve and sealed through a metal winding pad, the left end of the middle pipe is connected with the nylon plug and sealed through the first O-shaped ring, and the flange at the right end of the middle pipe is connected with a flange plate at the end of the compression pipe and sealed through a fifth O-shaped ring; the heavy piston is installed in the center tube, the left end of the heavy piston with the nylon plug is tightly attached, the peripheral surface of the heavy piston is provided with an O-shaped ring groove and a guide groove, and a first guide belt and a third O-shaped ring are installed in the guide groove and the O-shaped ring groove.

Still further, the compression pipe comprises a thrust ring, a compression pipe body and a nozzle A, wherein the thrust ring is welded on one third of the circumference of the rear end of the compression pipe body and used for positioning, and the nozzle A is installed at the rear end of the compression pipe body.

Still further, compression pipe strutting arrangement includes rail wheel, support frame main part, support bolt board, runner, supporting seat, apron, bolt group C, bolt group D and lock round nut, the support frame main part is formed by bottom plate, support column and roof welding, the screw rod welding the support bolt board of integrative structure is constituteed at the bottom surface center of going up the backup pad. The steel rail wheel is connected to the bottom plate and matched with the steel rail in position, the rotating wheel and the locking round nut are connected to a central hole of the top plate, the upper supporting plate is connected to the screw rod through the screw rod and located on the upper surface and the lower surface of the top plate, the supporting seat is connected to the upper supporting plate through a bolt group C, the cover plate is connected to the compression pipe in a buckling mode and is connected and fastened with the supporting seat through a bolt group D, and the cover plate and the supporting seat form a round fixing hole for supporting the compression pipe; specifically, runner, screw rod and locking round nut constitute a set of micromatic setting, adjust the height of going up the backup pad through rotatory runner, screw up locking round nut lock after adjusting the height.

Furthermore, the compression pipe thrust device comprises a thrust support seat, a thrust support plate, a rear thrust plate, a polyurethane anti-collision pad, a front thrust plate, a first roller, a bolt group E, a bolt group F and a bolt group G, wherein two parts of the rear thrust plate, the polyurethane anti-collision pad and the front thrust plate can enclose a round hole with the same size as the outer diameter of the compression pipe, so that the compression pipe thrust device is convenient to mount; the front thrust plate is abutted and limited with the thrust ring, the thrust ring is fixedly connected to the peripheral surface of one third of the tail end of the compression pipe in a welding mode, the front thrust plate, the polyurethane anti-collision pad and the rear thrust plate are connected to the thrust support plate through a bolt group H, a U-shaped opening for placing a first roller is formed in the thrust support plate, and the top of the thrust support plate is designed to be in a U-shaped opening shape.

Still further, the heavy piston stopping device comprises a hollow connecting main body, stopping blocks, spacing blocks, nut accessories, a shell, a pressing plate, a fixing screw B, a damping flange, a screw assembly, a related tightening part and a guide part, wherein the two T-shaped stopping blocks are symmetrically arranged on the connecting main body through the spacing blocks and are locked through the nut accessories, the shell is sleeved on the spacing blocks and is tightened through the fixing screw B, and the pressing plates on two sides are tightly pressed on the shell and are fastened through the screw assembly; a sixth O-shaped ring is arranged on a pressing surface of the connecting body and the shell, a seventh O-shaped ring is arranged on an inner hole surface of the connecting body matched with the stopping block, an eighth O-shaped ring is arranged on a pressing surface of the stopping block and the spacing block, and a ninth O-shaped ring and a second guide belt are arranged on a matching surface of the spacing block and the shell;

the connecting body is close to the one end of experiment cabin is provided with the damping, the damping leads to the installation in connecting body's hole, damping department flange inserts in the hole of damping, connecting body with be provided with tenth O type circle on the downthehole face of damping contact, the damping with be provided with the third guidance tape on the outer peripheral face of connecting body contact and eleventh O type circle, damping department flange with be provided with fourth guidance tape and fourteenth O type circle on the outer peripheral face of damping contact, damping department flange with be provided with twelfth O type circle and thirteenth O type circle on the contact surface of connecting body and experiment cabin main part respectively. The connecting body is provided with a first air inlet and outlet hole and a second air inlet and outlet hole, the first air inlet and outlet hole and the second air inlet and outlet hole correspond to the damping and are respectively positioned on two sides of a step surface of the damping center, the flange at the damping position is provided with a threaded hole, the flange at the damping position is ejected out by screws, and the damping is pulled out by a sleeve pulling technology.

Still further, the experiment chamber comprises a hollow experiment chamber main body, an axial observation window assembly and an observation window assembly, wherein the experiment chamber main body is connected with the connecting main body through a bolt group, and the observation window assemblies for radial observation are symmetrically arranged on the operating side and the non-operating side of the experiment chamber main body; the upper side of the outer peripheral surface of the experiment cabin main body is provided with five connectors B which are used for connecting a thermocouple probe, a pressure sensor, an optical fiber probe and the like to collect relevant signal data in the experiment process. The left side of the experiment cabin main body is provided with a large round angle, so that a vortex is prevented from being generated in the experiment section. The experiment chamber main body is provided with a plurality of adjusting cushion blocks with different quantities and different sizes according to the compression ratio required by the experiment, the adjusting cushion blocks are fixed through screws and nuts, the surfaces of the two screws are inclined by 30 degrees with the horizontal plane, the interference of the screws on data measurement can be reduced through the arrangement, the adjustable range of the compression ratio is 16-40, the compression ratio is adjusted by increasing the compression ratio by 1 when adding one adjusting cushion plate according to the principle that the adjusting cushion block is firstly enlarged and then reduced in thickness when the compression ratio is adjusted from right to left, and the compression ratio is 16 when the adjusting cushion block is not put;

the end of the experiment cabin body is provided with an axial observation window assembly which comprises an end cover, organic glass for axial observation and an experiment cabin flange, wherein the end cover is connected to the experiment cabin flange through a fixing screw C; a fifteenth O-shaped ring is arranged on the contact surface of the experiment chamber flange and the end cover, a sixteenth O-shaped ring is arranged on the contact surface of the experiment chamber flange and the organic glass for axial observation, and a seventeenth O-shaped ring is arranged on the compression surface of the experiment chamber main body and the experiment chamber flange; the observation window assembly comprises an observation window large flange, an observation window middle flange, an observation window end cover, observation window glass, corresponding fasteners and sealing elements, the observation window large flange is welded on the experiment cabin main body, and the central hole of the observation window large flange is coaxial with the radial observation hole on the experiment cabin main body, the observation window end cover and the observation window large flange are provided with an observation window middle flange, the observation window end cover and the observation window middle flange are connected through a fixing screw D and then locked on the observation window large flange through a bolt group I, the observation window glass is arranged in the central groove of the observation window middle flange, a second rubber gasket is arranged between the observation window glass and the observation window end cover, an eighteenth O-shaped ring is arranged on the contact surface of the large observation window flange and the middle observation window flange, and a nineteenth O-shaped ring is arranged on the contact surface of the observation window middle flange and the observation window glass.

Still further, experiment cabin strutting arrangement includes pillar, experiment cabin backup pad and second gyro wheel, be provided with a plurality of through-holes of being connected with the bottom surface on the bottom plate of pillar, the pillar welding is in experiment cabin backup pad bottom surface center, the rotatable placing of second gyro wheel is in the U type inslot of experiment cabin backup pad, the arc surface of second gyro wheel with the contact of experiment cabin main part is supported.

Still further, the high-pressure source comprises a high-pressure pipe body, an upper end flange plate, a front end cover, a rear end cover, a connector C and corresponding sealing elements, the high-pressure pipe body is supported and placed on a bottom plate of the compression pipe supporting device, the upper end flange plate is welded on a connecting hole in the side face of the high-pressure pipe body, the upper end flange plate is connected with the bottom face of the ball valve through a bolt group and sealed through a metal winding pad, and the front end cover and the rear end cover are connected with flange plates at two ends of the high-pressure pipe body through a bolt group K and sealed through a twentieth O-shaped ring; the front end cover is provided with a nozzle C for charging and discharging air for a high-pressure source.

Compared with the prior art, the invention has the beneficial technical effects that:

the invention discloses a fuel supercritical combustion test device which comprises a hydraulic pushing device, a nylon plug, a heavy piston mounting section, a heavy piston, a compression pipe supporting device, a compression pipe thrust device, a heavy piston stopping device, an experiment cabin and a high-pressure source, wherein the hydraulic pushing device, the nylon plug, the heavy piston mounting section, the heavy piston, the compression pipe, the heavy piston stopping device and the experiment cabin are sequentially arranged to form a test line; the steel rail wheel at the bottom of the compression pipe supporting device is matched with a steel rail on the ground, so that the compression pipe, the ball valve and the high-pressure source can move synchronously, and the installation is convenient. The arrangement of the compression pipe thrust device improves the safety of experimental equipment and determines the height of the experimental equipment; meanwhile, the compression pipe supporting device is provided with a fine adjustment device, so that the supporting height of the compression pipe can be adjusted, and the condition that the bending stress at a certain position of the device is overlarge is prevented from occurring, and the experimental result is indirectly influenced. The heavy piston stopping device has double functions of heavy piston stopping and pneumatic buffering, the principle of heavy piston stopping is that a stopping block is pushed out of a stopping groove by high-pressure gas, the stopping block enters and exits the stopping groove by combining the compressibility of the gas, and further the stopping of a heavy piston is realized, and the operation is convenient and rapid; the structure of the retaining block is skillfully designed, and one side of the retaining block, which faces the heavy piston, is a conical surface, so that the heavy piston can be smoothly extruded back into the retaining block groove when being impacted; the principle of pneumatic buffering is that the head of the heavy piston impacts damping after passing through the retaining block, the damping is pushed to move backwards, air in a rear annular high-pressure space formed by the damping and a flange at the damping position of the connecting body is further compressed, the piston is made to do deceleration motion with increasing acceleration until reaching a limit position, and the motion is stopped. A large round angle is arranged at the left side of the test section, so that a vortex is prevented from being generated inside the test section; the compression ratio of the experimental equipment is adjusted by increasing or decreasing the adjusting cushion blocks in the experimental cabin, and the equipment can adjust the compression ratio between 16 and 40. The compression ratio directly affects the pressure of the gas filled into the compression pipe and directly affects the experimental result. The screws are inserted into the adjusting cushion blocks, and the plane where the two screws are arranged on each side is inclined by 30 degrees with the horizontal plane, so that the interference of the screws on data measurement is reduced.

The invention has the advantages of ingenious conception and compact and reasonable layout, greatly improves the stopping efficiency of the heavy piston and the safety in the stopping process, reduces the high stress strain at the moment of contact between the stopping block and the heavy piston, and prolongs the service life of the heavy piston and the stopping block. Meanwhile, a plurality of cushion blocks for changing the gas compression ratio are arranged, so that the function of the equipment is expanded. The application of the heavy piston driver can provide a uniform high-temperature and high-pressure static gas environment for fuel combustion, the experimental time reaches hundreds of milliseconds, and the measurement of experimental parameters is facilitated.

Drawings

The invention is further illustrated in the following description with reference to the drawings.

FIG. 1 is a schematic view of a fuel supercritical combustion test apparatus according to the present invention;

FIG. 2 is a schematic view of a hydraulic pushing apparatus according to the present invention;

FIG. 3 is a cross-sectional view of the hydraulic pushing apparatus of the present invention;

FIG. 4 is a schematic view of a heavy piston installation section of the present invention;

FIG. 5 is a cross-sectional view of the heavy piston mounting section of the present invention;

FIG. 6 is a schematic view of a compression tube of the present invention;

FIG. 7 is a schematic view of a compression tube support apparatus of the present invention;

FIG. 8 is a front view of the compression tube support apparatus of the present invention;

FIG. 9 is a schematic view of the compression tube thrust stop of the present invention;

FIG. 10 is a front view of the heavy piston check device and test chamber of the present invention;

FIG. 11 is a partial cross-sectional view of the heavy piston check device of FIG. 10 taken at the C-C position of the present invention;

FIG. 12 is a front cross-sectional view of the heavy piston check device of the present invention;

FIG. 13 is a cross-sectional view taken at the location A-A of FIG. 10 in accordance with the present invention;

FIG. 14 is a front sectional view of an experimental chamber according to the present invention;

FIG. 15 is a cross-sectional view taken at the location B-B of FIG. 10 in accordance with the present invention;

FIG. 16 is a schematic view of a holding device for an experimental chamber according to the present invention;

FIG. 17 is a schematic view of a high pressure source according to the present invention;

FIG. 18 is a front cross-sectional view of the high pressure source of the present invention;

description of reference numerals: 1. a hydraulic pushing device; 2. nylon plugging; 3. a heavy piston mounting section; 4. compressing the tube; 401. a check ring; 5. a compression tube support means; 6. a compression tube thrust device; 7. a heavy piston check device; 8. an experiment cabin; 9. an experiment chamber supporting device; 10. a steel rail; 11. a high voltage source; 12. a ball valve; 13. a heavy piston; 14. a metal wrap pad;

101. a rear bracket base; 102. rear support; 103. an oil cylinder; 104. the oil cylinder is supported in an auxiliary mode; 105. positioning pins; 106. a rotating shaft fixing cover; 107. a pressure bearing plate; 108. a fixing screw A; 109. a deep groove ball bearing; 110. a piston; 111. a cylinder block; 112. a bolt group A;

201. a first O-ring;

301. a T-shaped pipe sleeve; 302. an intermediate pipe; 303. a connecting flange; 304. a first air inlet aperture; 305. a second air inlet aperture; 306. a bolt group B; 307. a second O-ring; 308. a first guide belt; 309. a third O-ring; 310. a fourth O-ring; 311. a fifth O-ring;

401. a thrust ring; 402. compressing the tube body; 403. a nozzle A;

501. a rail wheel; 502. a base plate; 503. a support pillar; 504. a top plate; 505. a rotating wheel; 506. a screw; 507. an upper support plate; 508. a supporting seat; 509. a cover plate; 510. a bolt group C; 511. a bolt group D; 512. locking the round nut; 513. a bracket bolt plate; 514. a support frame main body;

601. a thrust bracket base; 602. a thrust support plate; 603. a rear thrust plate; 604. a polyurethane crash pad; 605. a front thrust plate; 606. a first roller; 607. a bolt group E; 608. a bolt group F; 609. a bolt group G; 610. a bolt group H;

701. a connecting body; 702. a backstop block; 703. a spacing block; 704. a nut fitting; 705. a housing; 706. pressing a plate; 707. a fixing screw B; 708. damping; 709. a damping place flange; 710. a sixth O-ring; 711. a seventh O-ring; 712. an eighth O-ring; 713. a ninth O-ring; 714. a second guide belt; 715. a screw assembly; 716. a tenth O-ring; 717. a third guide belt; 718. an eleventh O-ring; 719. a twelfth O-ring; 720. a thirteenth O-ring; 721. a fourth guide belt; 722. a fourteenth O-ring; 723. a first air inlet/outlet hole; 724. a second air inlet/outlet hole; 725. a third air inlet and outlet hole; 726. a fourth air inlet and outlet hole;

8-1, an axial viewing window assembly; 8-2, an observation window assembly; 801. an experiment cabin main body; 802. an experiment cabin flange; 803. an end cap; 804. organic glass for axial observation; 805. a first rubber pad; 806. a set screw C; 807. a fifteenth O-ring; 808. a sixteenth O-ring; 809. a seventeenth O-ring; 810. adjusting the cushion block; 811. a nozzle B; 812. a large flange of the observation window; 813. an observation window middle flange; 814. a set screw D; 815. an observation window end cover; 816. an observation window glass; 817. a bolt group I; 818. a screw; 819. a nut; 820. an eighteenth O-ring; 821. a nineteenth O-ring; 822. a second rubber pad; 823. a bolt group J;

901. a pillar; 902. an experiment cabin supporting plate; 903. a second roller;

1101. a high pressure pipe body; 1102. an upper flange plate; 1103. a front end cover; 1104. a rear end cap; 1105. a nozzle C; 1106. a twentieth O-ring; 1107. a bolt group K;

Detailed Description

As shown in fig. 1-18, a fuel supercritical combustion test apparatus comprises a hydraulic pushing device 1, a nylon plug 2, a heavy piston installation section 3, a compression pipe 4, a compression pipe supporting device 5, a compression pipe thrust device 6, a heavy piston check device 7, a test chamber 8, a test chamber supporting device 9, a steel rail 10, a high pressure source 11, a ball valve 12 and a heavy piston 13, wherein the hydraulic pushing device 1, the nylon plug 2, the heavy piston installation section 3, the heavy piston 13, the compression pipe 4, the heavy piston check device 7 and the test chamber 8 are sequentially arranged to form a test line, the nylon plug 2 is arranged on one side of the heavy piston installation section 3 close to the hydraulic pushing device 1, the bottom of the heavy piston installation section 3 is communicated with the high pressure source 11 through the ball valve 12, the compression pipe 4 is supported by two compression pipe supporting devices 5, the compression pipe supporting devices 5 are slidably placed on the steel rail 10, the compression tube thrust device 6 is arranged on the 401 thrust ring part of the compression tube 4, the high-pressure source 11 is arranged on the bottom bracket of the compression tube supporting device 5, and the heavy piston check device 7 is connected with the experiment cabin 8 and supported by the experiment cabin supporting device 9.

As shown in fig. 2 and 3, the hydraulic pushing device 1 includes a rear bracket base 101, a rear support 102, an oil cylinder 103, an auxiliary oil cylinder support 104, a positioning pin 105, a rotating shaft fixing cover 106, a bearing plate 107, a fixing screw a108, a deep groove ball bearing 109, a piston 110, an oil cylinder base 111 and a bolt set a112, a round bracket is disposed on the rear bracket base 101, a rotating end of the bottom of the rear support 102 passes through the deep groove ball bearing 109 and is connected in the round bracket, a positioning pin 105 is disposed at a corner of the rear support 102, the positioning pin 105 penetrates through the rear support 102 and is embedded and connected in a rotation-preventing hole on the top surface of the rear bracket base 101, a rotating shaft fixing cover 106 is disposed on the bottom surface of the rotating end of the rear support 102, the rotating shaft fixing cover 106 is fixed on the rear support 102 by the screw, the oil cylinder 103 and the oil cylinder base 111 are connected on the rear support 102 by the bolt set a112, the lower part of the front end of the oil cylinder 103 is lapped on the oil cylinder auxiliary support 104, the oil cylinder auxiliary support 104 is fixed on the top plate of the rear bracket base 101 through the fixing screw A108, a piston 110 is arranged in the oil cylinder 103, and the end part of the piston 110 is connected with the bearing plate 107. The specific oil cylinder 103 adopts a 25T oil cylinder, and the head of a piston 110 in the oil cylinder is connected with a bearing plate 107 in an interference fit manner; the rotating shaft fixing cover 106 is connected to the bottom surface of the rear support 102 through bolts, and the design of the deep groove ball bearing 109 can reduce the friction between curved surfaces; and a through hole for fixedly connecting the rear support seat 101 with the ground is formed in the bottom plate.

As shown in fig. 4 and 5, the heavy piston mounting section 3 comprises a T-shaped pipe sleeve 301, an intermediate pipe 302, a connecting flange 303, a bolt group B306 and corresponding fittings, wherein the T-shaped pipe sleeve 301 and the connecting flange 303 are fastened through the bolt group B306 and sealed through a fourth O-ring 310; the middle pipe 302 penetrates through a central hole of the T-shaped pipe sleeve 301 and an inner hole of the connecting flange 303, a second O-shaped ring 307 is arranged on a contact surface between the connecting flange 303 and the middle pipe 302, a positioning boss is arranged at the right end of the middle pipe 302, an air inlet and an air outlet at the bottom of the T-shaped pipe sleeve 301 are connected with the ball valve 12 and sealed through a metal winding pad 14, the left end of the middle pipe 302 is connected with the nylon plug 2 and sealed through a first O-shaped ring 201, and a right flange of the middle pipe 302 is connected with a flange plate at the end part of the compression pipe 4 and sealed through a fifth O-shaped ring 311; the heavy piston 13 is installed in the central tube 302, the left end of the heavy piston 13 is tightly attached to the nylon plug, and the circumferential surface of the heavy piston 13 is provided with an O-ring groove and a guide groove for installing a first guide belt 308 and a third O-ring 309. Specifically, the middle pipe 302 is specifically set as a compression pipe with a grating, the connecting flange 303 adopts an open end cover, the grating is required to be positioned at the center of the inner side of the T-shaped pipe sleeve and tightly attached to the nylon plug during installation, a first small air inlet hole 304 and a second small air inlet hole 305 are arranged on the exposed side walls of the two sides of the middle pipe 302, wherein percussion gas enters through the first small air inlet hole 304 and can push the heavy piston 13 to move forwards, and the second small air inlet hole 305 can be used for vacuumizing, inflating and washing gas; when the valve works, the ball valve 12 is opened, high-pressure gas in the high-pressure source 12 enters the middle pipe 302 sequentially through the ball valve 12 and a grid on the T-shaped pipe sleeve 301, the triggering gas is filled to push the heavy piston to move forwards, and when 309 is positioned at the grid position end, the gas in the high-pressure source 12 becomes a main force for pushing the heavy piston to move;

as shown in fig. 6, the compression pipe includes a thrust collar 401, a compression pipe body 402, and a nozzle a403, the thrust collar 401 is welded to a third of the circumference of the rear end of the compression pipe body 402 for positioning, and the nozzle a403 is installed at the rear end of the compression pipe body 402 for connecting a vent pipe to perform vacuum pumping, gas filling, and gas washing operations.

As shown in fig. 7 and 8, the compression pipe supporting device 5 includes a rail wheel 501, a supporting frame main body 511, a supporting frame bolt plate 513, a rotating wheel 505, a supporting base 508, a cover plate 509, a bolt group C510, a bolt group D511, and a locking round nut 512, wherein the supporting frame main body 511 is formed by welding a bottom plate 502, a supporting column 503, and a top plate 504, and the screw 506 is welded on the supporting frame bolt plate 513 which is formed into an integral structure at the center of the bottom surface of the upper supporting plate 507. The steel rail wheel 501 is connected to the bottom plate 502 and is matched with the position of the steel rail 10, the rotating wheel 505 and the locking round nut 510 are connected to the central hole of the top plate 506, the upper support plate 507 is connected to the screw rod 505 through the screw rod 506 and is positioned on the upper surface and the lower surface of the top plate 504, the support seat 508 is connected to the upper support plate 507 through a bolt group C510, the cover plate 509 is connected to the compression pipe 4 in a buckling manner and is connected and fastened with the support seat 508 through a bolt group D511, and the cover plate 509 and the support seat 508 form a round fixing hole for supporting the compression pipe 4; specifically, the rotating wheel 505, the screw 506 and the locking round nut 512 form a group of fine adjustment devices, the height of the upper supporting plate 507 is adjusted by rotating the rotating wheel 505, and the locking round nut 512 is screwed to be locked after the height is adjusted.

As shown in fig. 9, the compression pipe thrust stop 6 includes a thrust bracket base 601, a thrust support plate 602, a rear thrust plate 603, a polyurethane crash pad 604, a front thrust plate 605, a first roller 606, a bolt group E607, a bolt group F608, and a bolt group G609, the thrust support plate 602 is mounted on the top surface of the thrust bracket base 601 through the bolt group E607, the rear thrust plate 603 is two upper and lower blocks and side lugs are fixed together through the bolt group F608, the polyurethane crash pad 604 is two upper and lower blocks and is located between the front thrust plate 603 and the rear thrust plate 606, and the front thrust plate 605 is two left and right blocks and side lugs are connected together through the bolt group G609. The front thrust plate 605 abuts against and is limited by the thrust ring 401, the thrust ring 401 is fixedly connected to the peripheral surface of one third of the tail end of the compression pipe 4 in a welding mode, the front thrust plate 605, the polyurethane anti-collision pad 604 and the rear thrust plate 603 are connected to the thrust support plate 602 through a bolt group H610, a U-shaped opening for placing a first roller 606 is formed in the thrust support plate 602, and the two first rollers 606 which are arranged side by side play a role in assisting in supporting the compression pipe 4; specifically, the top of the thrust support plate 602 is designed to be in a U-shaped opening shape and used for placing the compression pipe 4, two parts of the rear thrust plate 603, the polyurethane crash pad 604 and the front thrust plate 605 can enclose a round hole with the same size as the outer diameter of the compression pipe 4, so that the installation is convenient, the two parts of the rear thrust plate 603 and the front thrust plate 605 are connected by using a bolt group F608, so that the overall rigidity is effectively improved, and the polyurethane crash pad 604 plays a role in buffering and damping. The front thrust plate 605 can prevent the thrust ring 401 from directly acting on the polyurethane crash pad 604, thereby improving the service life of the polyurethane crash pad 604.

As shown in fig. 10, 11, 12 and 13, the heavy piston anti-back device 7 includes a hollow connecting body 701, an anti-back block 702, a spacing block 703, a nut fitting 704, a housing 705, a pressing plate 706, a fixing screw B707, a damper 708, a flange 709 at the damper, a screw assembly 715, and related tightening members and guiding members, wherein the two T-shaped anti-back blocks 702 are symmetrically installed on the connecting body 701 through the spacing block 703, the connecting end of the anti-back block 702 penetrates through the spacing block 703 and then is locked by the nut fitting 704, the housing 705 is sleeved on the spacing block 703 and is tightened by the fixing screw B707, the pressing plates 706 on the two sides are pressed on the housing 705 and are tightened by the screw assembly 715; a sixth O-ring 710 is arranged on the pressing surface of the connecting body 701 and the shell 705, a seventh O-ring 711 is arranged on the inner hole surface of the connecting body 701 matched with the backstop block 702, an eighth O-ring 712 is arranged on the pressing surface of the backstop block 702 and the spacing block 703, and a ninth O-ring 713 and a second guide belt 714 are arranged on the matching surface of the spacing block 703 and the shell 705; the O-shaped rings at the joints play a role in sealing, and the guide belt is mainly applied to parts with relative motion to play a role in guiding. Specifically, before the experiment, high-pressure gas is filled into the outer air chambers on the two sides of the shell 705 through the third air inlet 725, the retaining block 702 is pushed out of the retaining groove, when the heavy piston 13 passes through the heavy piston retaining device 7, the chamfer on the head of the heavy piston 13 presses the retaining block 702 into the retaining groove on the connecting body 701 towards the two sides, at this time, the pressure of the air chamber outside the spacing block 703 is increased, after the head of the heavy piston 13 passes through the retaining block, when the head impacts the damping 708 and reaches the limit position, the retaining ring groove on the front section of the heavy piston 13 passes through the retaining block 702, the retaining block 702 automatically pops up under the high pressure action of the outer air chamber and is clamped into the retaining ring groove, so that the heavy piston 13 is locked, the heavy piston is prevented from being pushed back by the high-pressure gas at the experiment chamber 8, the retaining effect is achieved, and meanwhile, the effective data acquisition time is prolonged. After the experiment, in the operation of resetting the heavy piston 13, it is necessary to vent air through the third air inlet and outlet 725, vent the fourth air inlet and outlet 726 to make the spacing block 703 and the retaining block 702 move outwards, and finally return into the retaining groove of the connecting body 701.

The connecting body 701 is provided with a damper 708 at one end close to the experimental chamber, the damper 708 is installed in an inner hole of the connecting body 701 in a penetrating manner, a damper flange 709 is inserted into the inner hole of the damper 708, a tenth O-ring 716 is arranged on the inner hole surface of the connecting body 701 contacting the damper 708, a third guide belt 717 and an eleventh O-ring 718 are arranged on the outer peripheral surface of the damper 708 contacting the connecting body 701, a fourth guide belt 721 and a fourteenth O-ring 722 are arranged on the outer peripheral surface of the damper flange 709 contacting the damper 708, and a twelfth O-ring 719 and a thirteenth O-ring 720 are respectively arranged on the contact surfaces of the damper flange 709 with the connecting body 701 and the experimental chamber body 801. Specifically, the connecting body 701 is provided with a first air inlet and outlet hole 723 and a second air inlet and outlet hole 724, the first air inlet and outlet hole 723 and the second air inlet and outlet hole 724 correspond to the damper 708 and are respectively located on two sides of a central step surface of the damper 708 for manually controlling a damping position, during an experiment, the damper needs to be moved backwards by filling air with a certain pressure through the second air inlet and outlet hole 724, the damper is far away from a flange surface of the damper flange 722, and the heavy piston 13 can collide with an end surface of the damper 708 to perform deceleration movement with increasing acceleration until reaching an extreme position and stop when passing through the heavy piston stopping device 7. When the damping place flange 709 is detached, the damping place flange 709 is ejected out by using the screw and the threaded hole of the damping place flange 709, and the damping 708 is pulled out by using a sleeve pulling technology.

As shown in fig. 10, 14 and 15, the experiment chamber 8 comprises a hollow experiment chamber main body 801, an axial observation window assembly 8-1 and an observation window assembly 8-2, wherein the experiment chamber main body 801 and the connecting main body 701 are connected together through a bolt group, and the observation window assemblies for radial observation are symmetrically arranged on the operating side and the non-operating side of the experiment chamber main body 801; the upper side of the outer peripheral surface of the experiment cabin body 801 is provided with a plurality of nozzles B811, and the left side of the experiment cabin body 801 is provided with a large round angle to prevent vortexes from being generated in the experiment section. Specifically, in the present embodiment, five nozzles B811 are installed and located on the same cross section, and the nozzles B811 are used for connecting a thermocouple probe, a pressure sensor, an optical fiber probe, and the like, and are used for measuring and transmitting relevant signal parameters in an experimental process. When the experiment table works, different quantities of adjusting cushion blocks 810 with different sizes are placed in the experiment chamber according to the compression ratio required by the experiment, the screw rods 818 are inserted into the adjusting cushion blocks 810, the plane where the two screw rods 818 are arranged on each side is inclined by 30 degrees with the horizontal plane, the arrangement can reduce the interference of the screw rods 818 on data measurement, the adjustable range of the compression ratio is 16-40, the compression ratio is adjusted according to the principle that the adjusting cushion blocks are placed from right to left and then are placed in a small thickness, the compression ratio is increased by 1 when the adjusting cushion block is added, the compression ratio is 16 when the adjusting cushion block is not placed, and the compression ratio is adjusted to 40 when 24 blocks are filled as shown in figure 14.

The end of the experiment cabin body 801 is provided with an axial observation window assembly 8-1 which comprises an end cover 803, an organic glass 804 for axial observation and an experiment cabin flange 802, wherein the end cover 803 is connected to the experiment cabin flange 802 through a fixing screw C806, the experiment cabin flange 802 is connected with the end face flange of the experiment cabin body 801 through a bolt group J823, the organic glass 804 for axial observation is installed in a central groove of the experiment cabin flange 802, and a first rubber mat 805 is arranged between the organic glass 804 for axial observation and the end cover 803; a fifteenth O-shaped ring 807 is arranged on the contact surface of the experiment chamber flange 802 and the end cover 803, a sixteenth O-shaped ring 808 is arranged on the contact surface of the experiment chamber flange 802 and the organic glass 804 for axial observation, and a seventeenth O-shaped ring 809 is arranged on the compression surface of the experiment chamber main body 801 and the experiment chamber flange 802; the observation window assembly 8-2 comprises a large observation window flange 812, a middle observation window flange 813, an end observation window cover 815, an observation window glass 816 and corresponding fasteners and sealing members, wherein the large observation window flange 812 is welded on the experiment chamber main body 801, the central hole of the large observation window flange 812 is coaxial with the radial observation hole on the experiment chamber main body 801, the end observation window cover 815 and the large observation window flange 812 are provided with an intermediate observation window flange 813, the end observation window cover 815 and the intermediate observation window flange 813 are locked on the large observation window flange 812 through a bolt group I817 after being connected through a fixing screw D814, the observation window glass 816 is installed in the central groove of the intermediate observation window flange 813, a second rubber gasket 822 is arranged between the end observation window glass 816 and the end observation window cover 815, an eighteenth O-ring 820 is arranged on the contact surface of the large observation window flange 812 and the intermediate observation window flange 813, a nineteenth O-ring 821 is arranged on the contact surface of the observation window middle flange 813 and the observation window glass 816. Specifically, the design of a plurality of O-shaped rings on the matching surfaces of the first rubber mat 805, the second rubber mat 822 and the part effectively ensures the sealing performance of the experiment chamber, and is beneficial to forming a high-pressure closed space, and in addition, the first rubber mat 805 and the second rubber mat 822 have the damping effect, so that the phenomenon that the observation window glass is broken by vibration is avoided.

As shown in FIG. 16, the test chamber support means 9 comprises a support column 901, a test chamber support plate 902 and a second roller 903, wherein the bottom plate of the support column 901 is provided with a plurality of through holes connected with the bottom surface, the support column 901 is welded at the center of the bottom surface of the test chamber support plate 902, the second roller 903 is rotatably placed in a U-shaped groove of the test chamber support plate 902, and the arc-shaped surface of the second roller 903 is in contact with and supported by the test chamber main body 801. The design of the experiment cabin supporting device 9 is consistent with the arc center height of a U-shaped groove for placing the compression pipe in the compression pipe thrust device 6, and the service life of equipment is prevented from being influenced due to the fact that one end of the experiment cabin supporting device is too heavy.

As shown in fig. 17 and 18, the high pressure source 11 includes a high pressure pipe body 1101, an upper flange 1102, a front cover 1103, a rear cover 1104, a connector C1105 and corresponding sealing members, the high pressure pipe body 1101 is supported and placed on the bottom plate 502 of the compression pipe supporting device 5, the upper flange 1102 is welded on a side connecting hole of the high pressure pipe body 1101, the upper flange 1102 is connected with the bottom surface of the ball valve 12 through a bolt set and sealed by a metal winding pad 14, and the front cover 1103 and the rear cover 1104 are connected with flanges at two ends of the high pressure pipe body 1101 through a bolt set K1107 and sealed by a twentieth O-ring 1106. Specifically, the front end cover 1103 is provided with a connector C1105 for connecting to an air vent to introduce high-pressure air to the high-pressure source, and the high-pressure source 11 is controlled by controlling the switch of the ball valve 12 to supply air to the heavy piston installation section 3.

The working process of the invention is as follows:

firstly, when in work, the heavy piston 13 is put in from the left end, the heavy piston 13 is jacked into the middle pipe 302 through the oil cylinder 103, and then the nylon plug 2 is jacked into the left central hole of the middle pipe 302 in the same way, so that the end surface of the nylon plug 2 and the left side of the compression pipe 4 are pressed tightly. To ensure the compression, the nozzle a on the compression tube needs to be charged with high pressure gas and then discharged with gas. The third air inlet 725 of the heavy piston stopping device 7 is used for filling high-pressure air into the outer air chambers on the two sides of the shell 705, and the stopping block 702 is pushed out of the stopping groove; the second air inlet/outlet hole 724 of the heavy piston stopping device 7 is filled with gas with certain pressure to make the damper 708 retreat away from the flange surface of the damper flange 722; after a strut for hanging liquid drops is placed in the experiment chamber main body 801, the compression pipes 4 at the two ends of the heavy piston 13 need to be vacuumized, premixed gas is introduced into a section of the middle pipe 302 or the connection nozzle A403 of the compression pipe 4, and the experiment preparation work is completed.

During the experiment, the switch of the ball valve 12 is firstly opened, so that the high-pressure source 11 supplies air for the heavy piston installation section 3 of the compression pipe, and at the moment, the high-pressure pipe body 1101, the ball valve 12, the heavy piston installation section 3 and the heavy piston 13 form a high-pressure closed space; then high-pressure air with the same pressure as the high-pressure source is filled into the first air inlet small hole 304 on the left side of the heavy piston installation section to push the heavy piston 13 to move forwards, when the third O-shaped ring 309 on the left side of the heavy piston passes through the grating on the middle pipe 302, the high-pressure source 11 and the space on the left side of the heavy piston 13 form a new high-pressure closed space to push the heavy piston 13 to move towards the right side at a high speed with constant pressure, when the heavy piston 13 passes through the heavy piston stopping device 7, the chamfer of the head of the heavy piston 13 presses the stopping block 702 outwards into the stopping block groove on the connecting main body 701, at the moment, the pressure of an outer air chamber on two sides of the shell 706 is increased, the arc end surface of the stopping block 702 and the heavy piston 13 slide in a friction manner, after the head of the heavy piston 13 passes through the stopping block 702, the head impacts the damping 708 and moves forwards together until the track position is reached, the stopping ring groove on the heavy piston 13 is aligned with the stopping block 702, and the two symmetrically arranged stopping blocks 702 are popped out to automatically stop the stopping groove under the pressure of the outer air chamber, the piston is clamped into a stopping ring groove of the heavy piston 13, so that the heavy piston 13 is locked and positioned, the heavy piston is prevented from being pushed back by high-pressure gas at an experimental cabin, and the purpose of stopping the heavy piston 13 is achieved. During which the hanging droplets will undergo a combustion reaction. The working principle of the test equipment is that the heavy piston 13 performs approximate adiabatic isentropic compression on gas, the mechanical energy of the heavy piston 13 is converted into the internal energy of the compressed gas with higher efficiency, and the temperature and the pressure of the gas are improved, so that the high-temperature and high-pressure environment in the test chamber 8 is realized.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. A fuel supercritical combustion test apparatus, characterized by: comprises a hydraulic pushing device (1), a nylon plug (2), a heavy piston mounting section (3), a compression pipe (4), a compression pipe supporting device (5), a compression pipe thrust device (6), a heavy piston stopping device (7), an experiment cabin (8), an experiment cabin supporting device (9), a steel rail (10), a high pressure source (11), a ball valve (12) and a heavy piston (13), wherein the hydraulic pushing device (1), the nylon plug (2), the heavy piston mounting section (3), the heavy piston (13), the compression pipe (4), the heavy piston stopping device (7) and the experiment cabin (8) are sequentially arranged to form a test line, the heavy piston mounting section (3) is close to one side of the hydraulic pushing device (1) and is provided with the nylon plug (2), the bottom of the heavy piston mounting section (3) is communicated with the high pressure source (11) through the ball valve (12), and the compression pipe (4) is supported by the two compression pipe supporting devices (5), the compression pipe supporting device (5) is slidably placed on a steel rail (10), the compression pipe thrust device (6) is installed on a thrust ring (401) part of the compression pipe (4), the high-pressure source (11) is arranged on a bottom bracket of the compression pipe supporting device (5), and the heavy piston stopping device (7) is connected with the experiment cabin (8) and supported by the experiment cabin supporting device (9);

the heavy piston backstop device (7) comprises a hollow connecting main body (701), a backstop block (702), a spacing block (703), a nut fitting (704), a shell (705), a pressing plate (706), a fixing screw B (707), a damper (708), a flange (709) at the damping part, a screw assembly (715), a related tightening part and a guide part, wherein the backstop block (702) is T-shaped, is symmetrically arranged on the connecting main body (701) through the spacing block (703) and is locked through the nut fitting (704), the shell (705) is sleeved on the spacing block (703) and is screwed through the fixing screw B (707), and the pressing plates (706) at two sides are pressed on two sides of the shell (705) and are fastened through the screw assembly (715); a sixth O-ring (710) is arranged on a pressing surface of the connecting body (701) and the shell (705), a seventh O-ring (711) is arranged on an inner hole surface of the connecting body (701) matched with the stopping block (702), an eighth O-ring (712) is arranged on a pressing surface of the stopping block (702) and the spacing block (703), and a ninth O-ring (713) and a second guide belt (714) are arranged on a matching surface of the spacing block (703) and the shell (705);

a damper (708) is arranged at one end of the connecting body (701) close to the experimental cabin (8), the damper (708) is installed in an inner hole of the connecting body (701), a damper flange (709) is inserted into the inner hole of the damper (708), a tenth O-ring (716) is arranged on the inner hole surface of the connecting body (701) contacting with the damper (708), a third guide belt (717) and an eleventh O-ring (718) are arranged on the outer peripheral surface of the damper (708) contacting with the connecting body (701), a fourth guide belt (721) and a fourteenth O-ring (722) are arranged on the outer peripheral surface of the damper flange (709) contacting with the damper (708), and a twelfth O-ring (719) and a thirteenth O-ring (720) are respectively arranged on the contact surfaces of the damper flange (709) with the connecting body (701) and the experimental cabin body (801), the connecting body (701) is provided with a first air inlet and outlet hole (723) and a second air inlet and outlet hole (724), the first air inlet and outlet hole (723) and the second air inlet and outlet hole (724) correspond to the damping (708) and are respectively located on two sides of a central step surface of the damping (708), the damping flange (709) is provided with a threaded hole, the damping flange (709) is ejected out by screws, and the damping (708) is pulled out by a sleeve pulling technology.

2. The fuel supercritical combustion testing apparatus according to claim 1, characterized in that: the hydraulic pushing device (1) comprises a rear support base (101), a rear support (102), an oil cylinder (103), an oil cylinder auxiliary support (104), positioning pins (105), a rotating shaft fixing cover (106), a bearing plate (107), a fixing screw A (108), a deep groove ball bearing (109), a piston (110), an oil cylinder base (111) and a bolt group A (112), wherein a round support is arranged on the rear support base (101), the rotating end of the bottom of the rear support (102) penetrates through the deep groove ball bearing (109) to be connected into the round support, the positioning pins (105) are arranged at the corner of the rear support (102), the positioning pins (105) penetrate through the rear support (102) and are embedded into the anti-rotating holes in the top surface of the rear support base (101), the rotating shaft fixing cover (106) is arranged on the bottom surface of the rotating end of the rear support (102), and the rotating shaft fixing cover (106) is fixed on the rear support (102) through screws, the oil cylinder (103) and the oil cylinder seat (111) are connected to the rear support (102) through a bolt group A (112), the lower part of the front end of the oil cylinder (103) is lapped on the oil cylinder auxiliary support (104), and the head of a piston (110) in the oil cylinder (103) is in interference fit connection with a pressure bearing plate (107); the oil cylinder auxiliary support (104) is fixed on a top plate of the rear support seat (101) through the fixing screw A (108), a piston (110) is arranged in the oil cylinder (103), and the end part of the piston (110) is connected with the pressure bearing plate (107); the rotating shaft fixing cover (106) is connected to the bottom surface of the rear support (102) through bolts, and a through hole for fixedly connecting the rotating shaft fixing cover with the ground is formed in the bottom plate of the rear support seat (101).

3. The fuel supercritical combustion testing apparatus according to claim 1, characterized in that: the heavy piston mounting section (3) comprises a T-shaped pipe sleeve (301), an intermediate pipe (302), a connecting flange (303), a bolt group B (306) and corresponding fittings, wherein the T-shaped pipe sleeve (301) and the connecting flange (303) are fastened through the bolt group B (306) and sealed (310) through a fourth O-shaped ring; the middle pipe (302) penetrates through a center hole of the T-shaped pipe sleeve (301) and an inner hole of the connecting flange (303), a second O-shaped ring (307) is arranged on a contact surface of the connecting flange (303) and the middle pipe (302), a grating section is arranged in the middle of the middle pipe (302), air communication between the middle pipe (302) and the T-shaped pipe sleeve (301) is achieved, the middle pipe (302) is provided with a first air inlet small hole (304) for charging percussion gas and a second air inlet small hole (305) for vacuumizing, inflating and washing, a positioning boss is arranged at the right end of the middle pipe (302), the connecting flange (303) is mounted on the positioning boss, an air inlet and an air outlet at the bottom of the T-shaped pipe sleeve (301) are connected with the ball valve (12) and sealed through a metal winding pad (14), the left end of the middle pipe (302) is connected with the nylon plug (2) and sealed (201) through the first O-shaped ring, a right end flange of the middle pipe (302) is connected with a flange plate at the end part of the compression pipe (4) and is sealed (311) through a fifth O-shaped ring; heavy piston (13) are installed in the center tube, the left end of heavy piston (13) with nylon is stifled (2) and is hugged closely, the global of heavy piston (13) is provided with O type circle groove and direction trough of belt, first direction area (308) and third O type circle (309) are installed to direction trough of belt and O type circle inslot.

4. The fuel supercritical combustion testing apparatus according to claim 1, characterized in that: the compression pipe (4) comprises a thrust ring (401), a compression pipe body and a connector A (403), wherein the thrust ring (401) is welded on one third of the circumference of the rear end of the compression pipe body (402) for positioning, and the connector A (403) is installed at the tail end of the compression pipe body (402).

5. The fuel supercritical combustion testing apparatus according to claim 4, characterized in that: the compression pipe supporting device (5) comprises a steel rail wheel (501), a supporting frame main body (514), a support bolt plate (513), a rotating wheel (505), a screw (506), an upper supporting plate (507), a supporting seat (508), a cover plate (509), a bolt group C (510), a bolt group D (511) and a locking round nut (512), wherein the supporting frame main body (514) is formed by welding a bottom plate (502), a supporting column (503) and a top plate (504), and the screw (506) is welded on the support bolt plate (513) which is formed into an integral structure at the center of the bottom surface of the upper supporting plate (507); the steel rail wheel (501) is connected to the bottom plate (502) and matched with the steel rail (10), the rotating wheel (505) and the locking round nut (512) are connected to the central hole of the top plate (504) and located on the upper surface and the lower surface of the top plate (504), the supporting seat (508) is connected to the upper supporting plate (507) through a bolt group C (510), the cover plate (509) is connected to the compression pipe (4) in a buckling mode and is connected and fastened with the supporting seat (508) through a bolt group D (511), and the cover plate (509) and the supporting seat (508) form a round fixing hole for supporting the compression pipe (4); the rotating wheel (505), the screw rod (506) and the locking round nut (512) form a group of fine adjustment devices, the height of the upper supporting plate (507) is adjusted by rotating the rotating wheel (505), and the locking round nut (512) is screwed and locked after the height is adjusted.

6. The fuel supercritical combustion testing apparatus according to claim 4, characterized in that: the compression pipe thrust device (6) comprises a thrust support seat (601), a thrust support plate (602), a rear thrust plate (603), a polyurethane anti-collision pad (604), a front thrust plate (605), a first roller (606), a bolt group E (607), a bolt group F (608), a bolt group G (609) and a bolt group H (610), wherein two parts of the rear thrust plate (603), the polyurethane anti-collision pad (604) and the front thrust plate (605) can enclose a round hole with the same size as the outer diameter of the compression pipe (4) so as to be convenient to mount, the thrust support plate (602) is mounted on the top surface of the thrust support seat (601) through the bolt group E (607), the rear thrust plate (603) is divided into an upper block and a lower block, side lugs are fixed together through the bolt group F (608), the polyurethane anti-collision pad (604) is divided into an upper block and a lower block and is located between the front thrust plate (605) and the rear thrust plate (603), the front thrust plate is divided into a left thrust plate and a right thrust plate, and side lugs are connected together through a bolt group G (609); the front thrust plate (605) is abutted and limited with the thrust ring (401), the front thrust plate (605), the polyurethane anti-collision pad (604) and the rear thrust plate (603) are connected to the thrust support plate (602) through a bolt group H (610), a U-shaped opening for placing a first roller (606) is formed in the thrust support plate (602), and the top of the thrust support plate (602) is designed to be in a U-shaped opening shape.

7. The fuel supercritical combustion testing apparatus according to claim 1, characterized in that: the experiment cabin (8) comprises a hollow experiment cabin main body (801), an axial observation window assembly (8-1) and an observation window assembly (8-2), the experiment cabin main body (801) is connected with the connecting main body (701) through a bolt group, and the observation window assemblies (8-2) for radial observation are symmetrically arranged on the operating side and the non-operating side of the experiment cabin main body (801); the upper side of the peripheral surface of the experiment cabin main body (801) is provided with five nozzles B (811) which are used for connecting a thermocouple probe, a pressure sensor and a fiber probe and collecting related signal data in the experiment process; the left side of the experiment cabin main body (801) is provided with a large fillet to prevent the interior of the experiment section from generating vortexes; the experiment chamber main body (801) is provided with adjusting cushion blocks (810) with different quantities and sizes according to the compression ratio required by an experiment, the adjusting cushion blocks (810) are fixed through screws (818) and nuts (819), the plane where the two screws (818) are located and the horizontal plane are arranged in an inclined manner of 30 degrees, the interference of the screws (818) on data measurement can be reduced through the arrangement, the adjustable range of the compression ratio is 16-40, when the compression ratio is adjusted, according to the principle that the adjusting cushion blocks (810) are placed from right to left, the adjusting cushion blocks (810) are firstly enlarged and then the adjusting cushion blocks (810) are reduced, the compression ratio is increased by 1 when one adjusting cushion block (810) is added, and when the adjusting cushion blocks (810) are not placed, the compression ratio is 16;

the tail end of the experiment cabin body (801) is provided with an axial observation window assembly (8-1) which comprises an end cover (803), organic glass (804) for axial observation and an experiment cabin flange (802), the end cover (803) is connected to the experiment cabin flange (802) through a fixing screw C (806), the experiment cabin flange (802) is connected with an end face flange of the experiment cabin body (801) through a bolt group J (823), the organic glass (804) for axial observation is installed in a central groove of the experiment cabin flange (802), and a first rubber mat (805) is arranged between the organic glass (804) for axial observation and the end cover (803); a fifteenth O-shaped ring (807) is arranged on the contact surface of the experiment chamber flange (802) and the end cover (803), a sixteenth O-shaped ring (808) is arranged on the contact surface of the experiment chamber flange (802) and the axial observation organic glass (804), and a seventeenth O-shaped ring (809) is arranged on the compression surface of the experiment chamber main body (801) and the experiment chamber flange (802); the observation window assembly (8-2) comprises an observation window large flange (812), an observation window middle flange (813), an observation window end cover (815), an observation window glass (816) and corresponding fasteners and sealing pieces, wherein the observation window large flange (812) is welded on the experiment cabin main body (801), the central hole of the observation window large flange (812) is coaxial with the radial observation hole on the experiment cabin main body (801), the observation window end cover (815) and the observation window large flange (812) are provided with the observation window middle flange (813), the observation window end cover (815) and the observation window middle flange (813) are locked on the observation window large flange (812) through a bolt group I (817) after being connected through a fixing bolt D (814), the observation window glass (816) is installed in the central groove of the observation window middle flange (813), a second rubber gasket (822) is arranged between the observation window glass (816) and the observation window end cover (815), an eighteenth O-shaped ring (820) is arranged on the contact surface of the observation window large flange (812) and the observation window middle flange (813), and a nineteenth O-shaped ring (821) is arranged on the contact surface of the observation window middle flange (813) and the observation window glass (816).

8. The fuel supercritical combustion testing apparatus according to claim 7, characterized in that: the experimental cabin supporting device (9) comprises a support column (901), an experimental cabin supporting plate (902) and a second roller (903), wherein a plurality of through holes connected with the bottom surface are formed in the bottom plate of the support column (901), the support column (901) is welded at the center of the bottom surface of the experimental cabin supporting plate (902), the second roller (903) is rotatably placed in a U-shaped groove of the experimental cabin supporting plate (902), and the arc-shaped surface of the second roller (903) is in contact support with the experimental cabin main body (801).

9. The fuel supercritical combustion testing apparatus according to claim 4, characterized in that: the high-pressure source (11) comprises a high-pressure pipe body (1101), an upper end flange plate (1102), a front end cover (1103), a rear end cover (1104), a connector C (1105) and corresponding sealing elements, wherein the high-pressure pipe body (1101) is placed on a bottom plate of the compression pipe supporting device (5), the upper end flange plate (1102) is welded on a side connecting hole of the high-pressure pipe body (1101), the upper end flange plate (1102) is connected with the bottom surface of the ball valve (12) through a bolt group and sealed through a metal winding pad (14), and the front end cover (1103) and the rear end cover (1104) are connected with flange plates at two ends of the high-pressure pipe body (1101) through a bolt group K (1107) and sealed through a twentieth O-shaped ring (1106); the front end cover (1103) is provided with a nozzle C (1105) for charging and discharging air for a high pressure source.