CN115155681B

CN115155681B - Membraneless Shock Tube and Sampling System

Info

Publication number: CN115155681B
Application number: CN202210767410.3A
Authority: CN
Inventors: 王昆; 白世杰; 沈位; 梁兴雨; 罗逸伦
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2023-09-05
Anticipated expiration: 2042-06-30
Also published as: CN115155681A

Abstract

The invention provides a membraneless shock tube, comprising: a first conduit extending in a first direction adapted to be filled with a first gas; at least one second conduit extending in a second direction orthogonal to the first direction adapted to be filled with a second gas and in communication with the first conduit; a cutoff mechanism comprising: a stop assembly, at least a portion of which is configured to move in a first direction between a first position extending into the first conduit and a second position away from the first conduit; and an actuation assembly coupled to the closure assembly, adapted to hold the closure assembly in or out of the first position; the first pipeline and the second pipeline are closed when the stop assembly is in a first position, and the first pipeline and the second pipeline are conducted when the stop assembly is in a second position, so that shock waves are formed in the first pipeline based on the pressure difference between the second gas and the first gas. The invention also provides a sampling system which comprises the membraneless shock tube and a gas chromatograph-mass spectrometer.

Description

Membraneless shock tube and sampling system

Technical Field

The invention relates to the technical field of non-contact spectrum test research of gas temperature in a combustor, in particular to a membraneless shock tube and a sampling system.

Background

Shock tubes have been considered as a near zero-dimensional reactor as the first device to study the kinetics of high temperature chemical reactions. The conventional shock tube is a stainless steel vessel of circular or square cross-section divided into high and low pressure sections by a thin polyester film. The low pressure section was filled with the test mixture at room temperature and the drive section was filled with inert gas to high pressure until the membrane ruptured. When the diaphragm breaks, a large pressure differential causes a series of compression waves to propagate from the high pressure side to the low pressure side; these compression waves are superimposed together to form an incident shock wave.

The non-ideal rupture of the diaphragm of the traditional shock tube can lead to the entry of small diaphragm particles into a test area along with the driving gas, serious errors are generated on the experimental result, and when the flame speed is tested, the diaphragm can have a non-negligible influence on the expanding flame front. Moreover, due to the limited opening time of the diaphragm, the incident shock wave speed deviates from a theoretical value, the boundary layer is obviously increased, and the attenuation of the incident shock wave is serious; meanwhile, due to imperfect reflection of incident shock waves from the end wall, temperature gradient exists in the area after reflection and excitation, and the temperature and pressure change tends to be serious along with the increase of the observation time, and the temperature and pressure field is unevenly distributed.

Therefore, the conventional shock tube has the problems of low repeatability, interference of diaphragm debris and debris to experiments, long experimental period, large measurement uncertainty and the like.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides a membraneless shock tube and a sampling system, wherein a stop component is kept at a relative position extending into or separating from a first pipeline through an actuating component so as to realize the sealing or conduction of the first pipeline and a second pipeline, so that second gas enters the first pipeline to form shock waves in the conducted state of the first pipeline and the second pipeline.

In order to achieve the above object, there is provided as the present disclosure a membraneless shock tube comprising: a first conduit extending in a first direction adapted to be filled with a first gas; at least one second conduit extending in a second direction orthogonal to said first direction adapted to be filled with a second gas and communicating with said first conduit; a cutoff mechanism comprising: a shut-off assembly, at least a portion of the shut-off assembly configured to move in a first direction between a first position extending into the first conduit and a second position away from the first conduit; and an actuation assembly coupled to the shut-off assembly and adapted to hold the shut-off assembly in or out of the first position; the first pipeline and the second pipeline are communicated under the state that the stop assembly is positioned at the first position, and the first pipeline and the second pipeline are closed under the state that the stop assembly is positioned at the second position, so that shock waves are formed in the first pipeline based on the pressure difference of the second gas and the first gas.

In an exemplary embodiment, further comprising: a third pipe which is arranged at the end part of the first pipe opposite to the second pipe and is communicated with the first pipe; and a fourth pipe which is provided at an end of the third pipe opposite to the first pipe and communicates with the third pipe; the inner diameter of the third pipe gradually decreases from the end close to the first pipe to the end far from the first pipe; and a detection window and a sampling channel are arranged in the fourth pipeline.

In an exemplary embodiment, the actuating assembly is configured to apply an adjustable pressure to the shut-off assembly, the shut-off assembly being maintained in the first position with the actuating assembly applying a pressure greater than or equal to the pressure applied to the shut-off assembly by the first and second gases, the shut-off assembly being moved from the first position to the second position with the actuating assembly applying a pressure less than the pressure applied to the shut-off assembly by the first and second gases.

In an exemplary embodiment, the cutoff assembly includes: the fixing part is arranged on the first pipeline and/or the second pipeline; the first-stage moving part is sleeved in the fixed part, the other moving parts are sleeved in the adjacent moving parts step by step, at least one-stage moving part stretches into the first pipeline to seal the first pipeline and the second pipeline in the state of the first position, and each-stage moving part is separated from the first pipeline to conduct the first pipeline and the second pipeline in the state of the second position; the fixing part comprises a first end cover, and the first end cover is arranged on the second pipeline; the multi-stage moving part includes: a first sleeve disposed within the first end cap, the first end of the first sleeve configured to face the second conduit being movable between a third position extending from the first end cap and a fourth position retracting into the first end cap; and a first piston having a second end nested within the first sleeve, a third end of the first piston opposite the second end being configured to move between the first and second positions, the second end extending circumferentially outward to form a first flange that abuts an opposing end surface of the first sleeve in the third position to retain the first piston in the first position, the first piston moving in synchronization with the first sleeve in the third to fourth position, the first sleeve remaining in the fourth position, the first flange being disengaged from the first sleeve, the first piston moving to the second position; the radial middle part of the end part of the third end extends towards the first direction to form a first protruding part, and an arc-shaped surface is formed between the first protruding part and the outer edge of the third end so as to guide the second gas to enter the first pipeline along the arc-shaped surface.

In an exemplary embodiment, a plurality of first air holes are circumferentially arranged on the side wall of the first end cover at one axial position, a plurality of second air holes are circumferentially arranged on the side wall of the first end cover at another axial position, and a plurality of third air holes are circumferentially arranged on the side wall of the first sleeve at axial positions corresponding to the second air holes; the first sleeve and the first end cover define a first chamber, the first chamber is communicated with the second pipeline through the first air guide hole and is suitable for guiding the second air to enter the first chamber so as to apply a part of first pressure to the first sleeve, the first piston and the first sleeve define a second chamber, the second air guide hole is communicated with the third air guide hole in the state that the first sleeve is at the fourth position and is suitable for guiding the second air to enter the second chamber so as to apply a part of first pressure to the first piston.

In an exemplary embodiment, the actuation assembly includes: a pressing part, which is arranged on the first end cover and is suitable for filling third gas so as to apply second pressure to the first sleeve and the first piston through the third gas; and a release portion provided on the pressing portion and configured to move between a fifth position where the pressing portion is closed and a sixth position where the pressing portion is opened; the third gas is sealed among the pressing part, the first sleeve and the first piston in a state that the release part is at a fifth position so as to apply a second pressure higher than the first pressure to the first sleeve and the first piston, and the third gas is discharged to the air environment in a state that the release part is at a sixth position so as to enable the second pressure to be lower than the first pressure.

In an exemplary embodiment, the pressing portion includes: the fourth end of the second sleeve, which is opposite to the first end cover, is sleeved in the first end cover, and a plurality of first exhaust holes are circumferentially arranged on the side wall of the second sleeve, so that the interior of the second sleeve is communicated with the external gas environment; the second end cover is arranged at the end part of the second sleeve opposite to the first end cover, and a third chamber is defined among the second end cover, the second sleeve, the first end cover, the first sleeve and the first piston; the second piston is sleeved in the second sleeve and is configured to move between a seventh position for closing the first exhaust hole and an eighth position for opening the first exhaust hole, the second piston divides the third chamber into a first subchamber and a second subchamber, and the second piston is provided with a pressure equalizing hole which is suitable for conducting the first subchamber and the second subchamber; the end part of the fourth end, which is opposite to the first sleeve, extends towards the first sleeve to form a first limiting part, and the inner diameter of the first limiting part is larger than or equal to the outer diameter of the first piston, so that the first sleeve is limited to the fourth position and the first piston is allowed to pass until the first piston moves to a second position abutting against the fourth end; the second end cover is provided with an air inlet communicated with the third cavity, the second end cover is suitable for introducing third gas into the third cavity through the air inlet, and a first valve is arranged in the air inlet and is suitable for conducting or closing the air inlet.

In an exemplary embodiment, at least one fourth air vent is axially disposed on the second end cap, and the release portion includes: the third sleeve is arranged on the second end cover, and a fourth chamber is defined between the third sleeve and the second end cover; the third piston is sleeved in the third sleeve and is configured to move between a fifth position where the fourth air vent is closed and a sixth position where the fourth air vent is opened; the third piston divides the fourth chamber into a third subchamber and a fourth subchamber, a second exhaust hole is formed in the side wall of a third sleeve in the third subchamber, a third exhaust hole is formed in the side wall of a third sleeve in the fourth subchamber, and second valves are arranged in the second exhaust hole and the third exhaust hole and are suitable for conducting or closing the second exhaust hole and/or the third exhaust hole with the external air environment.

In an exemplary embodiment, the inner surface of the sidewall of the third sleeve extends radially inward to form a second stop adapted to retain the third piston in the sixth position; and the second exhaust hole and the third exhaust hole are both in an open state for conducting the fourth chamber with the external air environment in the state that the third piston is in the sixth position.

The disclosure also provides a sampling system comprising a membraneless shock tube and a gas chromatograph-mass spectrometer, which is communicated with a sampling channel of the membraneless shock tube.

According to the membraneless shock tube and sampling system disclosed herein, a first conduit communicates with a second conduit, and an actuation assembly is adapted to drive a shut-off assembly between a first position and a second position. The first pipe and the second pipe are closed when the stop component is in the first position. And the cut-off assembly is communicated with the second pipeline in the state of the second position, and second gas in the second pipeline enters the first pipeline so as to form shock waves in the first pipeline through the pressure difference of the second gas and the first gas.

Drawings

FIG. 1 is a cross-sectional view of a membraneless shock tube in accordance with an exemplary embodiment of the present invention;

FIG. 2 is a schematic illustration of the exemplary embodiment of the closure assembly of FIG. 1 in a first position;

FIG. 3 is a schematic illustration of the exemplary embodiment of the closure assembly of FIG. 1 in a second position;

FIG. 4 is a cross-sectional view of a fourth conduit portion of the illustrative embodiment shown in FIG. 1; and

fig. 5 is a block diagram of a sampling system according to an illustrative embodiment of the present invention.

In the drawings, the reference numerals specifically have the following meanings:

1. a first pipe;

2. a second pipe;

3. a third conduit;

4. a fourth conduit;

41. a second pair of windows;

42. a sampling port;

43. a first pair of windows;

44. a window;

45. a sampling channel;

46. a pressure sensor;

5. unloading the tank;

6. a stop mechanism;

61. a shut-off assembly;

611. a first sleeve;

6111. a third air vent;

612. a first piston;

613. a first end cap;

6131. a first air vent;

6132. a second air guide hole;

62. a pressing section;

621. a second sleeve;

6211. a first exhaust hole; 6212. a fourth end;

6213. a first limit part; 6214. damping vent holes;

622. a second piston;

6221. equalizing holes;

623. a second end cap;

6231. an air inlet hole;

6232. a fourth air guide hole;

63. a release section;

631. a third sleeve;

6311. a second exhaust hole; 6312. a third exhaust hole; 6313. a second limit part;

64. a first chamber;

65. a second chamber;

66. a third chamber;

67. a fourth chamber;

7. a gas chromatograph-mass spectrometer;

8. a first gas mixing tank;

9. a vacuum pump; and 10, a second gas mixing tank.

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The terms "comprises," "comprising," and/or the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components. All terms, including technical and scientific terms, used herein have the meaning commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be construed to have meanings consistent with the context of the present specification and should not be construed in an idealized or overly formal manner.

In this document, unless specifically stated otherwise, directional terms such as "upper," "lower," "left," "right," "inner," "outer," and the like are used to refer to an orientation or positional relationship shown based on the drawings, and are merely for convenience in describing the present invention, rather than to indicate or imply that the devices, elements, or components referred to must have a particular orientation, be configured or operated in a particular orientation. It should be understood that when the absolute positions of the described objects are changed, the relative positional relationship they represent may also be changed accordingly. Accordingly, these directional terms should not be construed to limit the present invention.

Where expressions like at least one of "A, B and C, etc. are used, the expressions should generally be interpreted in accordance with the meaning as commonly understood by those skilled in the art (e.g.," a system having at least one of A, B and C "shall include, but not be limited to, a system having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). Where a formulation similar to at least one of "A, B or C, etc." is used, in general such a formulation should be interpreted in accordance with the ordinary understanding of one skilled in the art (e.g. "a system with at least one of A, B or C" would include but not be limited to systems with a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).

Fig. 1 is a cross-sectional view of a membraneless shock tube in accordance with an exemplary embodiment of the present invention.

The illustrative embodiment of the present invention provides a membraneless shock tube, as shown in FIG. 1, comprising a first conduit 1, at least one second conduit 2, and a shut-off mechanism 6. The first conduit 1 extends in a first direction and is adapted to be filled with a first gas. The second conduit 2 extends in a second direction orthogonal to the first direction, is adapted to be filled with a second gas and communicates with the first conduit 1. The shut-off mechanism 6 comprises a shut-off assembly 61 and an actuation assembly, at least a portion of the shut-off assembly 61 being configured to move in a first direction between a first position extending into the first conduit 1 and a second position out of the first conduit 1. The actuation assembly is coupled to the shut-off assembly 61 and adapted to hold the shut-off assembly 61 in or out of the first position. In the state where the shutoff unit 61 is at the first position, the first pipe 1 and the second pipe 2 are closed, and in the state where the shutoff unit 61 is at the second position, the first pipe 1 and the second pipe 2 are connected to form a shock wave in the first pipe 1 based on a pressure difference between the second gas and the first gas.

In such an embodiment, the actuating assembly is adapted to drive the shut-off assembly 61 in the first position or to move to the second position, and to conduct the first conduit 1 and the second conduit 2 during movement from the first position to the second position. Therefore, a diaphragm is not required to be arranged between the first pipeline 1 and the second pipeline 2, and the influence of non-ideal fragmentation of the diaphragm on the test caused by the traditional shock tube can be effectively prevented.

In an exemplary embodiment, the first direction is characterized as a horizontal direction (up and down as shown in fig. 1) and the second direction is characterized as a vertical direction (left and right as shown in fig. 1).

In an exemplary embodiment, the first conduit 1 comprises a cylindrical conduit, including but not limited to.

In detail, the first pipe 1 is configured to have an inner diameter including, but not limited to, 210 mm and a wall thickness including, but not limited to, 50 mm.

Further, the first duct 1 is provided with at least one inlet adapted for the introduction of a first gas and at least one outlet adapted for the discharge of at least a portion of the first gas.

Further, as shown in fig. 1, an unloading tank 5 is further provided on the first pipe 1, and is adapted to absorb the reflected shock wave. Such an embodiment can effectively prevent secondary heating of shock waves.

In an exemplary embodiment, six second pipes 2 are included, and each second pipe 2 employs a pipe including, but not limited to, a ring pipe.

In detail, each annular tube is configured to be 1500 millimeters long, with an inner diameter including, but not limited to, 210 millimeters, and a wall thickness including, but not limited to, 50 millimeters.

Further, the air outlet sides of the six second pipes 2 are collected at the air inlet side of the first pipe 1.

Further, the roughness of the inner wall of the second pipe 2 is configured to Ra (surface roughness unit) <0.8, bearing pressure of 1000atm (one standard atmospheric pressure) or more, and temperature of 2000K (kelvin) or more.

In an exemplary embodiment, the second conduit 2 is provided with at least one inlet port adapted for the introduction of a second gas and a pressure relief port adapted for the relief of pressure.

Further, the second pipe 2 is also provided with a pressure sensor 46 and/or a vacuum gauge.

In an exemplary embodiment, the first gas includes, but is not limited to, a mixture of one or more of oxygen, nitrogen, air, carbon monoxide, carbon dioxide, nitric oxide, and water vapor.

Further, the second gas includes, but is not limited to, a mixture of one or more of acetylene, hydrogen, oxygen, nitrogen, argon, helium, and other inert gases.

Further, the pressure of the second gas in the second pipe 2 is greater than the pressure of the first gas in the first pipe 1, so that the second gas can enter the first pipe 1 to form shock waves with the first gas in a state that the second pipe 2 is communicated with the first pipe 1.

In such an embodiment, by setting the parameters described above (including but not limited to the first conduit 1, the second conduit 2, the first gas and the second gas), shock waves having Mach numbers greater than 1.6 can be generated during the test.

Fig. 4 is a cross-sectional view of a fourth conduit portion of the illustrative embodiment shown in fig. 1.

According to an embodiment of the present disclosure, as shown in fig. 1 and 4, the masless shock tube further includes a third pipe 3 and a fourth pipe 4. The third pipe 3 is provided at an end of the first pipe 1 opposite to the second pipe 2 (an upper end as shown in fig. 1) and communicates with the first pipe 1. The fourth pipe 4 is provided at an end (an upper end as shown in fig. 1) of the third pipe 3 opposite to the first pipe 1, and communicates with the third pipe 3. The inner diameter of the third pipe 3 gradually decreases from the end closer to the first pipe 1 (lower end as shown in fig. 1) to the end farther from the first pipe 1 (upper end as shown in fig. 1). A detection window and a sampling channel 45 are provided in the fourth pipe 4.

In an exemplary embodiment, the inner diameter of the end of the third pipe 3 (the lower end as viewed in fig. 1) facing the first pipe 1 is configured to coincide with the inner diameter of the first pipe 1.

In detail, as shown in fig. 1, the inner diameter of the upper end of the third pipe 3 is configured to be 105 mm, and the inner diameter of the lower end of the third pipe 3 is configured to be 210 mm.

Further, the wall thickness of the upper end of the third pipe 3 is configured to be 30 mm, and the wall thickness of the lower end of the third pipe 3 is configured to be 50 mm. In such an embodiment, the third conduit 3 is used to enhance the intensity of the laser wave.

In an exemplary embodiment, a plurality of pressure sensors 46 are disposed on the fourth conduit 4 at intervals along the first direction and are adapted to collect pressure signals at different axial locations within the fourth conduit 4.

In detail, including but not limited to three pressure sensors 46, the three pressure sensors 46 are disposed on the same side of the fourth pipe 4.

In an exemplary embodiment, the end of the fourth pipe 4 remote from the third pipe 3 is provided with a third end cap.

In detail, the third end cap is provided with a viewing window 44 and a sampling channel 45.

Further, the viewing window 44 cooperates with a photomultiplier tube (PMT) to make ignition delay time measurements for high speed imaging of the endwall surface. The sampling channel 45 performs on-line sampling measurement of the distribution of the intermediate products of the species and the like in combination with a gas chromatography-mass spectrometry (GC-MS) flight mass spectrometry (TOF-MS).

In an exemplary embodiment, the radial side wall of the fourth pipeline 4 is further provided with a sampling port 42, which is suitable for sampling the side wall and comparing and analyzing the species distribution in the vertical axis.

In an exemplary embodiment, the detection window comprises a first pair of windows 43 provided on a radial side wall of the fourth conduit 4, adapted for performing atomic resonance absorption spectroscopy, laser absorption spectroscopy, high-speed imaging, etc. measurements.

In an exemplary embodiment, the detection window further comprises a second pair of windows 41 further provided on the radial side wall of the fourth conduit 4, adapted for schlieren imaging, interferometry, and cooperating with the first pair of windows 43 for high-speed imaging, to construct a three-dimensional flame shape.

In such an embodiment, the schlieren method diagnoses through the second pair of windows 41 downstream of the fourth conduit 4, the online laser diagnoses through the first pair of windows 43, and the photomultiplier tube (PMT) test diagnoses through the window 44 of the third end cap, such that the samples form both sidewall and endwall samples.

Fig. 2 is a schematic illustration of the exemplary embodiment of the closure assembly of fig. 1 in a first position. Fig. 3 is a schematic illustration of the exemplary embodiment of fig. 1 with the shut-off assembly in a second position.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the actuating assembly is configured to apply an adjustable pressure to the blocking assembly 61, the blocking assembly 61 is maintained at the first position in a state where the pressure applied by the actuating assembly is greater than or equal to the pressure applied by the first gas and the second gas to the blocking assembly 61, and the blocking assembly 61 is moved from the first position to the second position in a state where the pressure applied by the actuating assembly is less than the pressure applied by the first gas and the second gas to the blocking assembly 61.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the shut-off assembly 61 includes a fixed part and a multistage moving part. The fixing part is arranged on the first pipeline 1 and/or the second pipeline 2. The first-stage moving part of the multistage moving part is sleeved in the fixed part, the other moving parts are sleeved in the adjacent moving parts step by step, at least one stage of moving part stretches into the first pipeline 1 to seal the first pipeline 1 and the second pipeline 2 in the state of the first position, and each stage of moving part is separated from the first pipeline 1 to conduct the first pipeline 1 and the second pipeline 2 in the state of the second position.

In such embodiments, the actuation assembly is adapted to apply a pressure to the shut-off assembly 61 that is opposite to the pressure applied by the first gas and the second gas. The multistage moving portion sequentially moves to a side closer to the pressurizing unit in a state where the pressure is smaller than the pressure applied by the first gas and the second gas. The moving part close to the fixed part drives the next-stage moving part to synchronously move in the initial stage of the moving process, so that the whole of the multi-stage moving part has a larger stress area and the speed is faster. In the middle and later stages of the moving process, when the first stage moving part moves to the limited position, the next stage moving part is separated from the first stage moving part to continue to move, and the mass of the subsequent multi-stage moving part is gradually reduced, so that the moving part extending into the first pipeline 1 is accelerated more, and the stage moving part is separated from the first pipeline 1 in a very small time (including but not limited to 1.56 ms or less) (so that the bottom surface of the first protruding part passes through the edge of the first pipeline 1 in the projection of the axial direction (such as the lower end part of the second pipeline 2 shown in fig. 3) to the time interval between the vertex of the first protruding part passing through the edge of the first pipeline 1), so as to realize the conduction of the first pipeline 1 and the second pipeline 2. In this way, the formation of shock waves is facilitated.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the fixing portion includes a first end cap 613, and the first end cap 613 is disposed on the second pipe 2.

In an exemplary embodiment, the outlet side of the second pipe 2 is configured as a cylindrical joint.

In detail, the first end cap 613 is provided on the cylindrical joint, and the axis of the first end cap 613 coincides with the extending direction of the axis of the joint.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the multistage moving portion includes a first sleeve 611 and a first piston 612. The first sleeve 611 is housed within the first end cap 613, and the first end of the first sleeve 611 configured to face the second pipe 2 is moved between a third position extended by the first end cap 613, and a fourth position retracted within the first end cap 613. The second end of the first piston 612 is sleeved in the first sleeve 611, a third end of the first piston 612 opposite to the second end is configured to move between a first position and a second position, the second end extends outwards along the circumferential direction to form a first flange, the first flange abuts against the opposite end surface of the first sleeve 611 to keep the first piston 612 in the first position when the first sleeve 611 is in the third position, the first piston 612 moves synchronously with the first sleeve 611 when the first sleeve 611 moves from the third position to the fourth position, and the first flange is separated from the first sleeve 611 and moves to the second position when the first sleeve 611 is kept in the fourth position.

In an exemplary embodiment, the first end of the first sleeve 611 abuts against the opposite end face of the first pipe 1 in the state in which the first sleeve 611 is in the third position.

In an exemplary embodiment, the outer diameter of the third end of the first piston 612 is approximately the same as the inner diameter of the first conduit 1.

In such an embodiment, the first sleeve 611 and the first piston 612 are in socket engagement, and together seal the first pipe 1 and the second pipe 2. Thus, the air tightness between the first pipeline 1 and the second pipeline 2 is improved, and the second gas can be effectively prevented from leaking into the first pipeline 1.

According to an embodiment of the present disclosure, a radially middle portion of an end portion of the third end of the first piston 612 extends in the first direction to form a first protrusion, and an arc surface is formed between the first protrusion and an outer edge of the third end to guide the second gas into the first pipe 1 along the arc surface.

In such an embodiment, the second gas is advantageously guided so as to enter the first duct 1 in a direction substantially tangential to the curved surface, so that the second gas is effectively prevented from being reflected in a direction orthogonal to the first duct 1.

According to the embodiment of the present disclosure, as shown in fig. 1 to 3, a plurality of first air guide holes 6131 are circumferentially provided on a side wall of the first end cap 613 at one axial position, a plurality of second air guide holes 6132 are circumferentially provided on a side wall of the first end cap 613 at another axial position, and a plurality of third air guide holes 6111 are circumferentially provided on a side wall of the first sleeve 611 at axial positions corresponding to the second air guide holes 6132. The first sleeve 611 and the first end cap 613 define a first chamber 64 therebetween, the first chamber 64 being in communication with the second conduit 2 through a first gas vent 6131, adapted to direct a second gas into the first chamber 64 to apply a portion of the first pressure to the first sleeve 611, the first piston 612 and the first sleeve 611 define a second chamber 65 therebetween, and the second gas vent 6132 is in communication with the third gas vent 6111 in a state in which the first sleeve 611 is in the fourth position, adapted to direct a second gas into the second chamber 65 to apply a portion of the first pressure to the first piston 612.

In such an embodiment, during the process of moving the first sleeve 611 from the third position to the fourth position, the first pressure provided by the second gas acts on the first sleeve 611, and the first pressure provided by the first gas acts on the first piston 612, so that the first sleeve 611 and the first piston 612 have larger stress areas, which is beneficial for the first sleeve 611 and the first piston 612 to accelerate. After the first piston 612 has a certain speed, the first sleeve 611 is limited to the fourth position, and in this state, the second gas is conducted through the second gas-guiding hole 6132 and the third gas-guiding hole 6111, so that the first pressure provided by the first gas only acts on the first piston 612, and further acceleration of the first piston 612 is achieved.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the actuating assembly includes a pressing portion 62 and a releasing portion 63. The pressing portion 62 is disposed on the first end cap 613 and is adapted to be filled with a third gas to apply a second pressure to the first sleeve 611 and the first piston 612 by the third gas. The release portion 63 is provided on the pressing portion 62 and is configured to move between a fifth position closing the pressing portion 62 and a sixth position opening the pressing portion 62. In the state where the release portion 63 is in the fifth position, the third gas is enclosed between the pressing portion 62, the first sleeve 611, and the first piston 612 to apply a second pressure greater than the first pressure to the first sleeve 611 and the first piston 612, and in the state where the release portion 63 is in the sixth position, the third gas is discharged to the air atmosphere to make the second pressure smaller than the first pressure.

In an exemplary embodiment, the third gas includes, but is not limited to, a mixture of one or more of oxygen, nitrogen, air, carbon monoxide, carbon dioxide, nitric oxide, and water vapor.

In such an embodiment, the pressing portion 62 is adapted to be filled with a third gas, and the third gas is sealed in a sealing space formed by the pressing portion 62, the first sleeve 611 and the first piston 612, so as to provide a second pressure to the first sleeve 611 and the first piston 612. In a state where the to-be-released portion 63 is moved to the sixth position, the pressing portion 62 is in communication with the outside air environment, and the second pressure is instantaneously close to zero. Thus, the first sleeve 611 and the first piston 612 can be accelerated to move toward the release portion 63 relatively rapidly under the first pressure.

According to an embodiment of the present disclosure, as shown in fig. 1 to 3, the pressing portion 62 includes a second sleeve 621, a second end cap 623, and a second piston 622. The fourth end 6212 of the second sleeve 621, which faces the first end cap 613, is sleeved in the first end cap 613, and a plurality of first exhaust holes 6211 are circumferentially formed in the sidewall of the second sleeve 621, which are adapted to communicate the interior of the second sleeve 621 with the external air environment. The second end cap 623 is disposed at an end of the second sleeve 621 opposite the first end cap 613, the second end cap 623, the second sleeve 621, the first end cap 613, the first sleeve 611, and the first piston 612 defining a third chamber 66 therebetween. The second piston 622 is sleeved in the second sleeve 621 and is configured to move between a seventh position for closing the first exhaust hole 6211 and an eighth position for opening the first exhaust hole 6211, the second piston 622 divides the third chamber 66 into a first subchamber and a second subchamber, and the second piston 622 is provided with a pressure equalizing hole 6221 adapted to communicate the first subchamber with the second subchamber.

In an exemplary embodiment, as shown in fig. 2 and 3, the middle portion of the second sleeve 621 is configured as a cylindrical-like portion and the end of the second sleeve 621 opposite the fourth end 6212 is configured as a frustoconical-like portion.

In detail, the cylindrical portion is provided with a first exhaust hole 6211.

Further, in the state where the second piston 622 is in the seventh position, the second piston 622 coincides with the first exhaust hole 6211 in projection in the radial direction to seal the first exhaust hole 6211. In the eighth position of the second piston 622, the second piston 622 is retracted into the truncated cone-like portion, and the second piston 622 is displaced from the first exhaust hole 6211, so that the first exhaust hole 6211 is in communication with the outside air environment, and the third gas is more rapidly exhausted to the outside air environment.

According to an embodiment of the present disclosure, as shown in fig. 2 and 3, the end of the fourth end 6212 facing the first sleeve 611 extends in the direction of the first sleeve 611 to form a first stop 6213, and the first stop 6213 has an inner diameter greater than or equal to the outer diameter of the first piston 612, adapted to limit the first sleeve 611 to the fourth position and allow the first piston 612 to pass until the first piston 612 moves to the second position against the fourth end 6212.

In an exemplary embodiment, an annular gap is formed between the outer edge of the first stop portion 6213 and the inner edge of the first end cap 613, the width of the gap being approximately the same as the thickness of the first sleeve 611.

In detail, the inner edge of the first stopper 6213 is substantially the same as the outer diameter of the second end of the first piston 612.

Further, the inner edge of the first stopper portion 6213 is configured as an inwardly protruding stepped portion.

In such an embodiment, in a state where the first sleeve 611 is moved to the fourth position, the first sleeve 611 is fitted in the gap, and the first stopper portion 6213 abuts against the first sleeve 611 to restrict the first sleeve 611 to the fourth position. At this time, the first piston 612 may continue to pass the inner edge of the first limiting portion 6213 until the first piston 612 abuts against the stepped portion to limit the first piston 612 to the second position.

In an exemplary embodiment, the second sleeve 621 is provided with a damper vent hole 6214, the vent end of the damper vent hole 6214 being disposed in the second end cap 623 opposite the gap.

In such an embodiment, since the first sleeve 611 is blocked by the first sleeve 611 in a state where the first sleeve 611 is inserted into the gap, most of the gas in the original gap is discharged only through the damper exhaust hole 6214, and the first sleeve 611 is blocked from moving from the third position to the fourth position, thereby damping the first sleeve 611. This cushions the first sleeve 611 to reduce the impact generated when the first sleeve 611 moves to the fourth position.

According to the embodiment of the present disclosure, as shown in fig. 2 and 3, an air inlet hole 6231 communicating with the third chamber 66 is provided on the second end cover 623, and is adapted to introduce the third air into the third chamber 66 through the air inlet hole 6231, and a first valve is provided in the air inlet hole 6231, and is adapted to open or close the air inlet hole 6231.

In one illustrative embodiment, the first valve includes, but is not limited to, a solenoid valve.

According to an embodiment of the present disclosure, as shown in fig. 2 and 3, at least one fourth gas vent 6232 is axially provided on the second end cap 623. The release portion 63 includes a third sleeve 631 and a third piston. The third sleeve 631 is disposed on the second end cap 623, with the fourth chamber 67 defined between the third sleeve 631 and the second end cap 623. The third piston is disposed in the third sleeve 631 and is configured to move between a fifth position in which the fourth air vent 6232 is closed and a sixth position in which the fourth air vent 6232 is opened. The third piston divides the fourth chamber 67 into a third sub-chamber and a fourth sub-chamber, a second exhaust hole 6311 is formed on the side wall of the third sleeve 631 located in the third sub-chamber, a third exhaust hole 6312 is formed on the side wall of the third sleeve 631 located in the fourth sub-chamber, and second valves are arranged in the second exhaust hole 6311 and the third exhaust hole 6312 and are suitable for conducting or closing the second exhaust hole 6311 and/or the third exhaust hole 6312 with the external air environment.

In an exemplary embodiment, the second valve includes, but is not limited to, a solenoid valve.

In an exemplary embodiment, a plurality of fourth air guide holes 6232 are provided in the second endcap 623.

In detail, the fourth air guide holes 6232 provided in the second end cap 623 are circularly symmetric.

In an exemplary embodiment, a plurality of second protrusions corresponding to the positions of the fourth gas vent holes 6232 are provided on an end surface of the third piston facing the second end cap 623.

In detail, the number of the second protrusions is identical to the number of the fourth air guide holes 6232.

Further, the second protrusion is shaped and sized to conform to the fourth gas vent 6232. In the state in which the third piston is in the fifth position, each second protrusion is embedded in the opposite fourth air vent 6232 to close each fourth air vent 6232.

In such an embodiment, the third piston and the second end cover 623 are engaged in a fitting manner, so as to provide a better sealing performance for the fourth chamber 67.

According to an embodiment of the present disclosure, as shown in fig. 2 and 3, an inner surface of a sidewall of the third sleeve 631 extends radially inward to form a second stop 6313 adapted to retain the third piston in the sixth position. In the sixth position of the third piston, the second exhaust hole 6311 and the third exhaust hole 6312 are both open to the fourth chamber 67 and the outside air environment.

In an exemplary embodiment, as shown in fig. 2, the first piston 612 is in a first position (the first piston 612 extends into the first conduit 1), the first end (upper end) of the first sleeve 611 is in a third position (extending from the first end cap 613 and resting against the first conduit 1), and the second piston 622 is in a seventh position (upper portion of the third chamber 66).

In this state, the third piston is in the fifth position (upper portion of the fourth chamber 67), and the fourth chamber 67 is filled with compressed gas and is in a sealed state. At this time, the sum of the pressure (P1) applied by the first gas to the first piston 612 and the pressure (P2) applied by the second gas to the first sleeve 611 is less than or equal to the sum of the pressure (P3) applied by the third gas to the first piston 612 and the first sleeve 611 and the friction force (Pf) between the first sleeve 611 and the first end cap 613 and between the first sleeve 611 and the first piston 612.

After the second valve is turned on, as shown in fig. 3, under the action of P1 and P2, the compressed air in the fourth chamber 67 is discharged along the second air discharge hole 6311 and the third air discharge hole 6312, respectively, the pressure of the first subchamber of the third chamber 66 is reduced (because the pressure equalizing hole 6221 is provided on the second piston 622, the pressure of the second subchamber is also reduced but the speed of the reduction is slower than that of the first subchamber), so that the second piston 622 moves to the eighth position (the lower part of the third chamber 66), and when the second piston 622 is dislocated from the first air discharge hole 6211, the third air is rapidly discharged to the outside air environment under the action of P1 and P2. At this time, the sum of P1 and P2 is greater than the sum of P3 and Pf, and the second gas sequentially enters the first chamber 64 and the second chamber 65, so that the first sleeve 611 moves toward the fourth position and the first piston 612 moves toward the second position until the first sleeve 611 is in the fourth position and the first piston 612 is in the second position.

The exemplary embodiment of the present invention also provides a sampling system, as shown in fig. 5, comprising a membraneless shock tube and a gas chromatograph-mass spectrometer 7 in communication with a sampling channel 45 of the membraneless shock tube.

In an exemplary embodiment, the sampling system further comprises a first gas mixing tank 8 adapted to mix at least two of the gases including, but not limited to, oxygen, nitrogen, air, carbon monoxide, carbon dioxide, nitric oxide, and water vapor to form a first gas.

In an exemplary embodiment, the sampling system further comprises a second gas mixing tank 10 adapted to mix at least two of one or more gases including, but not limited to, acetylene, hydrogen, oxygen, nitrogen, argon, helium, and other inert gases to form a second gas.

In an exemplary embodiment, the sampling system further comprises a vacuum pump 9 arranged between the first gas mixing tank 8 and the first conduit 1 and/or between the second gas mixing tank 10 and the second conduit 2, adapted to input or output a first gas into or out of the first conduit 1 and a second gas into or out of the second conduit 2.

Those skilled in the art will appreciate that the features recited in the various embodiments of the disclosure and/or in the claims may be provided in several combinations or combinations, even if such combinations or combinations are not explicitly recited in the disclosure. In particular, the features recited in the various embodiments of the present disclosure and/or the claims may be combined and/or combined in several ways without departing from the spirit and teachings of the present disclosure. All such combinations and/or combinations fall within the scope of the present disclosure.

The foregoing embodiments have been provided for the purpose of illustrating the general principles of the present invention, and are not meant to limit the invention thereto, but to limit the invention thereto.

Claims

1. A membraneless shock tube, comprising:

a first duct (1) extending in a first direction, adapted to be filled with a first gas;

at least one second duct (2) extending in a second direction orthogonal to said first direction, adapted to be filled with a second gas and communicating with said first duct (1);

A shut-off mechanism (6) comprising:

-a shut-off assembly (61), at least a portion of the shut-off assembly (61) being configured to move in a first direction between a first position protruding into the first conduit (1) and a second position leaving the first conduit (1), the shut-off assembly (61) comprising:

a fixing part arranged on the first pipeline (1) and/or the second pipeline (2); and

the multistage moving parts are sleeved in the fixed parts, the other moving parts are sleeved in the adjacent moving parts step by step, at least one stage of the moving parts extend into the first pipeline (1) to seal the first pipeline (1) and the second pipeline (2) in the state of the first position, and each stage of the moving parts are separated from the first pipeline (1) to conduct the first pipeline (1) and the second pipeline (2) in the state of the second position;

the fixing part comprises a first end cover (613), and the first end cover (613) is arranged on the second pipeline (2); the moving part includes: a first sleeve (611) housed inside the first end cap (613), the first end of the first sleeve (611) configured to face the second pipe (2) being moved between a third position protruding from the first end cap (613) and a fourth position retracted inside the first end cap (613); and a first piston (612), a second end of the first piston (612) being nested within the first sleeve (611), a third end of the first piston (612) opposite the second end being configured to move between the first position and a second position, the second end extending circumferentially outward to form a first flange, the first flange abutting against an opposing end face of the first sleeve (611) in the third position to retain the first piston (612) in the first position, the first piston (612) moving in synchronization with the first sleeve (611) in a state in which the first sleeve (611) is retained in the fourth position, the first flange being disengaged from the first sleeve (611) in a state in which the first piston (612) is moved to the second position; and

An actuation assembly, coupled to the shut-off assembly (61), adapted to hold the shut-off assembly (61) in or out of the first position;

the first pipeline (1) and the second pipeline (2) are closed when the stop assembly (61) is in the first position, and the first pipeline (1) and the second pipeline (2) are conducted when the stop assembly (61) is in the second position so as to form shock waves in the first pipeline (1) based on the pressure difference of the second gas and the first gas.

2. The membraneless shock tube of claim 1, further comprising:

a third pipe (3) which is provided at the end of the first pipe (1) opposite to the second pipe (2) and communicates with the first pipe (1); and

and a fourth pipe (4) which is provided at the end of the third pipe (3) opposite to the first pipe (1) and communicates with the third pipe (3).

3. Membraneless shock tube according to claim 2, characterized in that the inner diameter of the third pipe (3) gradually decreases from the end close to the first pipe (1) to the end distant from the first pipe (1).

4. Membraneless shock tube according to claim 2, characterized in that a detection window and a sampling channel (45) are provided in the fourth pipe (4).

5. The masless pipe of claim 1, wherein the actuation assembly is configured to apply an adjustable pressure to the shut-off assembly (61), the shut-off assembly (61) being maintained in the first position with the actuation assembly applying a pressure greater than or equal to the pressure applied by the first and second gases to the shut-off assembly (61), the actuation assembly applying a pressure less than the pressure applied by the first and second gases to the shut-off assembly (61), the shut-off assembly (61) being moved from the first position to the second position.

6. The membraneless shock tube of claim 1, characterized in that a radially middle part of the end part of the third end extends towards the first direction to form a first bulge, and an arc-shaped surface is formed between the first bulge and the outer edge of the third end to guide the second gas into the first pipeline (1) along the arc-shaped surface.

7. The membraneless shock tube of claim 1, wherein a plurality of first gas-guide holes (6131) are circumferentially arranged on a side wall of the first end cover (613) at one axial position, a plurality of second gas-guide holes (6132) are circumferentially arranged on a side wall of the first end cover (613) at another axial position, and a plurality of third gas-guide holes (6111) are circumferentially arranged on a side wall of the first sleeve (611) at axial positions corresponding to the second gas-guide holes (6132);

Wherein a first chamber (64) is defined between the first sleeve (611) and the first end cap (613), the first chamber (64) is in communication with the second conduit (2) through the first gas-guiding hole (6131), and is adapted to guide the second gas into the first chamber (64) to apply a portion of the first pressure to the first sleeve (611), a second chamber (65) is defined between the first piston (612) and the first sleeve (611), and in a state in which the first sleeve (611) is in the fourth position, the second gas-guiding hole (6132) is in communication with a third gas-guiding hole (6111), and is adapted to guide the second gas into the second chamber (65) to apply a portion of the first pressure to the first piston (612).

8. The masless shock tube of claim 7, wherein said actuation assembly comprises:

a pressing portion (62) provided on the first end cap (613) and adapted to be filled with a third gas so as to apply a second pressure to the first sleeve (611) and the first piston (612) by the third gas; and

a release portion (63) provided on the pressing portion (62) and configured to move between a fifth position where the pressing portion (62) is closed and a sixth position where the pressing portion (62) is opened;

Wherein the third gas is sealed between the pressing portion (62), the first sleeve (611) and the first piston (612) in a state in which the releasing portion (63) is at the fifth position to apply a second pressure greater than the first pressure to the first sleeve (611) and the first piston (612), and the third gas is discharged to the outside air environment in a state in which the releasing portion (63) is at the sixth position to make the second pressure smaller than the first pressure.

9. The membraneless shock tube of claim 8, wherein the pressure applying portion (62) comprises:

a second sleeve (621), wherein a fourth end (6212) of the second sleeve (621) facing the first end cap (613) is sleeved in the first end cap (613), and a plurality of first exhaust holes (6211) are circumferentially arranged on the side wall of the second sleeve (621), and are suitable for communicating the interior of the second sleeve (621) with the external air environment;

a second end cap (623) disposed at an end of the second sleeve (621) opposite the first end cap (613), the second end cap (623), the second sleeve (621), the first end cap (613), the first sleeve (611), and the first piston (612) defining a third chamber (66) therebetween;

The second piston (622) is sleeved in the second sleeve (621) and is configured to move between a seventh position for closing the first exhaust hole (6211) and an eighth position for opening the first exhaust hole (6211), the second piston (622) divides the third chamber (66) into a first subchamber and a second subchamber, and the second piston (622) is provided with a pressure equalizing hole (6221) which is suitable for conducting the first subchamber and the second subchamber.

10. The membraneless shock tube of claim 9, characterized in that the end of the fourth end (6212) facing the first sleeve (611) extends in the direction of the first sleeve (611) forming a first stop (6213), and that the inner diameter of the first stop (6213) is greater than or equal to the outer diameter of the first piston (612), adapted to limit the first sleeve (611) to the fourth position and allow the first piston (612) to pass until the first piston (612) moves to a second position abutting against the fourth end (6212).

11. The membraneless shock tube of claim 10, characterized in that an air inlet hole (6231) is arranged on the second end cover (623) and is communicated with the third chamber (66), the air inlet hole (6231) is suitable for introducing the third air into the third chamber (66), and a first valve is arranged in the air inlet hole (6231) and is suitable for conducting or closing the air inlet hole (6231).

12. The membraneless shock tube of claim 11, characterized in that at least one fourth gas vent (6232) is axially provided on the second end cap (623), the release portion (63) comprising:

a third sleeve (631) disposed on the second end cap (623), the third sleeve (631) and the second end cap (623) defining a fourth chamber (67) therebetween; and

a third piston, which is sleeved in the third sleeve (631), and is configured to move between a fifth position where the fourth air vent (6232) is closed and a sixth position where the fourth air vent (6232) is opened;

the third piston divides the fourth chamber (67) into a third subchamber and a fourth subchamber, a second exhaust hole (6311) is formed in the side wall of a third sleeve (631) in the third subchamber, a third exhaust hole (6312) is formed in the side wall of the third sleeve (631) in the fourth subchamber, and second valves are arranged in the second exhaust hole (6311) and the third exhaust hole (6312) and are suitable for conducting or closing the second exhaust hole (6311) and/or the third exhaust hole (6312) with the external air environment.

13. The maser tube of claim 12, wherein an inner surface of a sidewall of the third sleeve (631) extends radially inward to form a second stop (6313) adapted to retain the third piston in the sixth position;

wherein, in the state that the third piston is at the sixth position, the second exhaust hole (6311) and the third exhaust hole (6312) are both in an open state that connects the fourth chamber (67) with the external air environment.

14. A sampling system, comprising:

a membraneless shock tube according to any one of claims 1 to 13; and

and the gas chromatograph-mass spectrometer (7) is communicated with the sampling channel (45) of the membraneless shock tube.