CN111751074A - Detonation-driven high-enthalpy shock tunnel automatic inflation control system - Google Patents
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Abstract
The invention discloses a detonation-driven high-enthalpy shock tunnel automatic inflation control system, which comprises: a shock tunnel; a plurality of gas supply lines; a control gas source for adjusting the pressure; and the control unit comprises an NI control card connected with each electronic pressure regulator through a network cable, preset pressure values are stored in the electronic pressure regulators, the NI control card respectively acquires real-time pressure signals in the upstream and the driving sections of each electronic pressure regulator, then the real-time pressure signals are compared with the preset pressure values, corresponding high-pressure pneumatic valves or constant-pressure reducers are adjusted according to difference values until the pressure of each air source is balanced with the preset pressure values, then the driving sections are simultaneously inflated, and the inflation of each air source is stopped after the mixed pressure of each air source in the driving sections reaches the specified requirement. The invention adopts the Ethernet communication to control the NI control card to input and output analog quantity and digital quantity, realizes remote accurate control on the electronic voltage regulator and automatic switch control on the high-pressure pneumatic valve, and eliminates the danger in the detonation experiment process.
Description
Technical Field
The invention relates to the field of wind tunnel tests, in particular to a detonation-driven high-enthalpy shock tunnel automatic inflation control system capable of inputting gas pressure through remote automatic detonation.
Background
The high enthalpy shock tunnel is a test device for generating high-speed and high-temperature airflow and is used for a performance test of a hypersonic aircraft. The detonation-driven shock tunnel is one kind of high enthalpy shock tunnel, and it utilizes the controlled detonation combustion of combustible gas to drive and compress test gas and produces high enthalpy test gas flow through the expansion of spray pipe.
The hypersonic aircraft has very high flying speed, and the temperature of air after stagnation on the surface of the aircraft can reach thousands of degrees or even tens of thousands of degrees, so that the vibration excitation, dissociation and even ionization of air molecules are caused, and high-temperature real gas effect phenomena are generated, and the phenomena have complex and essential influences on the aspects of aerodynamic force, aerodynamic heat, photoelectric characteristics and the like of the hypersonic aircraft, so that hypersonic flow predicted by the classical gas dynamics theory has very large deviation, and a challenging research subject is brought to the development of the hypersonic aircraft. The research on hypersonic high enthalpy flow becomes one of the leading subjects of modern gas dynamics research, and although 70 years of related research has been carried out at home and abroad, the hypersonic flow theory and the calculation method are greatly developed, the ground test is still an important means and a key data source for hypersonic high enthalpy flow research due to the high temperature gas medium and the complexity of the flow thereof.
The high-enthalpy shock tunnel is one of key ground test devices for researching a hypersonic flow rule, and can simulate a total temperature and total pressure test environment within a Mach number of 5-30. According to different driving modes, the high enthalpy shock wave wind tunnels can be divided into three categories: heated light gas drive, free piston drive, and detonation drive. The operation cost of the light gas driving is relatively high, and the heated high-temperature and high-pressure hydrogen can generate serious erosion effect on equipment; the experimental airflow quality provided by free piston driving is not high, the repeatability is poor, and the high enthalpy simulation capability is limited; the detonation drive test has long time and low operation cost, and the detonation wave high-temperature and high-pressure gas is used as the driving gas, so that the detonation drive test is a more convenient and effective strong driving method, and can simulate higher enthalpy value and larger time scale.
The detonation-driven shock tunnel adopts mixed gas as initial gas, generates gas-phase detonation by ignition, and generates strong incident shock waves because the pressure after detonation is far greater than the pressure of the mixed gas and the sound velocity is also far higher than that of the driven gas. The key technologies of detonation-driven shock tunnel operation include an inflation and uniform mixing technology, a high-performance detonation technology, a suture operation technology and the like, wherein the inflation and uniform mixing are the most important links in an experiment, the gas mixing ratio and the spatial distribution thereof have important influences on detonation initiation and detonation product characteristics, and the high repeatability of the detonation-driven experiment also depends on the uniform mixing of initial gas.
At present, the inflation system of the detonation-driven shock tunnel in China basically adopts a critical nozzle inflation principle, the inflation proportion is controlled by utilizing that the outlet back pressure does not influence the gas mass flow after the throat of the nozzle reaches the sonic velocity, the upstream pressure of the critical nozzle is adjusted by a manual pressure regulator, and people need to watch on the spot to ensure that the pressure fluctuation is within a certain range. The gas with the equivalence ratio, such as oxyhydrogen with the equivalence ratio of 2:1, filled in the detonation drive has certain danger, so that the manual pressure reducer platform is generally far away from the position of the inflation throat to ensure safety. However, the method causes the problem of pressure drop after the gas is transmitted in a long-distance pipeline, further causes inaccuracy of the upstream pressure value of the inflation throat, and further causes inaccuracy of the inflation mixing ratio. Particularly, in the operation of a high enthalpy shock tunnel, the initial gas inflation pressure value can reach 40-50 atm, and the safety threat to inflation monitoring personnel is greater. Therefore, in the operation process of the high enthalpy detonation-driven shock tunnel, a set of automatic and accurate inflation control system needs to be developed.
Disclosure of Invention
The invention aims to provide a detonation-driven high-enthalpy shock tunnel automatic inflation control system capable of inputting gas pressure through remote automatic detonation.
Specifically, the invention provides a detonation-driven high-enthalpy shock tunnel automatic inflation control system, which comprises:
the shock tunnel is used for carrying out a high enthalpy test and is sequentially divided into an explosion unloading section, a driving section, a driven section, a spray pipe and a test chamber;
the air supply pipeline comprises a plurality of air sources and conveying pipelines which respectively convey the air sources and are connected with the driving section, and an electronic pressure regulator and a high-pressure pneumatic valve are respectively arranged on each conveying pipeline;
the control air source comprises an air source and a control pipeline for connecting the air source with each high-pressure pneumatic valve, and a constant-pressure reducer is arranged on the control pipeline;
and the control unit comprises an NI control card connected with each electronic pressure regulator through a network cable, preset pressure values are stored in the electronic pressure regulators, the NI control card respectively acquires real-time pressure signals at the upper streams of the electronic pressure regulators and in the driving section, then the real-time pressure signals are compared with the preset pressure values in the electronic pressure regulators, corresponding high-pressure pneumatic valves or constant-pressure reducers are adjusted according to difference values until the pressure of each gas source is balanced with the preset pressure values, then the driving section is simultaneously inflated, and the inflation of each gas source is stopped after the mixed pressure of each gas source in the driving section reaches the specified requirement.
In one embodiment of the invention, the conveying pipeline is further provided with a filter for filtering impurities in the gas, a critical throat for preventing the influence of back pressure, a sonic nozzle connected with the driving section, and on-off valves arranged at the control parts.
In one embodiment of the invention, the nozzle comprises a contraction section and an expansion section, the contraction section is formed by contraction of the connecting end of the driven section, the expansion section is in a bell mouth shape formed by expansion of the contraction section towards the test chamber, the minimum diameter of the contraction section is smaller than the diameter of the driven section, and the maximum diameter of the expansion section is larger than the diameter of the driven section.
In one embodiment of the present invention, the NI control card comprises an AO module for outputting an analog quantity, an AI module for inputting an analog quantity, and a DO module for outputting a digital signal.
In one embodiment of the present invention, the connection points of the delivery pipes of the air supply line and the driving section are located on the same cross section, and the connection points are symmetrically distributed.
In one embodiment of the invention, the gas source comprises hydrogen, oxygen and nitrogen.
In one embodiment of the invention, the connection points of the hydrogen, oxygen and nitrogen gas and the driving section are at 120 ° to each other, and the three gas jets first collide with each other after filling the driving section, and then achieve thorough mixing.
In one embodiment of the present invention, the mixing pressure of each air source in the driving section reaching the specified requirement is: when the mixed gas generates a reflection shock wave during detonation and the contact surface interacts with each other, no reflection can be generated on the contact surface so as to meet the requirement of sewing the contact surface, wherein the conditions of sewing the contact surface are as follows:
in the formula, a4And a1Respectively representing sound velocities of different wave system regions generated after detonation, wherein Ms is an incident shock wave Mach number.
In one embodiment of the invention, the pressure of the gas source upstream of the electronic pressure regulator is determined in the following manner:
the mass flow of gas through the sonic nozzle is obtained by:
in the formula A*The area of the throat is shown as the area of the throat,
respectively, molecular weight, specific heat ratio, universal gas constant, p0,T0The total pressure and the total temperature of an outlet of the electronic pressure regulator are shown;
the mixing ratio of different gases is essentially the molar ratio of the gases, and if the mixing ratio of two gases in the mixed gas is n, the mixing ratio comprises the following components:
substituting equation (2) into equation (3) yields:
when the total temperature remains constant, i.e. (T)0)1≈(T0)2Then, the simplification is:
it is thus determined that the gas pressure upstream of the electronic pressure regulator needs to meet the requirements of equation (5).
According to the invention, the NI control card is controlled by Ethernet communication to input and output analog quantity and digital quantity, and a visual graphic operation interface is adopted, so that the remote accurate control of an electronic voltage regulator and the automatic on-off control of a high-pressure pneumatic valve are realized, and the danger in the detonation experiment process is eliminated; the remote accurate control and the whole-course inflation pressure monitoring function of the electronic pressure regulator are utilized to adjust the high-pressure pneumatic valve to carry out automatic on-off control, so that the inflation parameters in the test process are accurate and reliable, and the detonation operation result has good repeatability, therefore, the scheme has stable performance, accurate inflation parameters and good expansibility.
Drawings
FIG. 1 is a schematic structural diagram of a shock tunnel according to an embodiment of the present invention;
FIG. 2 is a diagram of a travel wave system generated by detonation gases in a shock tunnel according to an embodiment of the present invention;
FIG. 3 is a schematic view of an automatic inflation control system according to one embodiment of the present invention;
FIG. 4 is a schematic diagram of the control circuitry of the control unit in accordance with one embodiment of the present invention;
FIG. 5 is a diagram of CJ pressures following detonation with 20% fluctuation in the respective proportions of hydrogen, oxygen and nitrogen charges;
FIG. 6 shows a values of a after detonation, when the respective charge ratios of hydrogen, oxygen and nitrogen fluctuate by 20%4A fluctuation range diagram;
FIG. 7 is a schematic diagram of an automatic pressure regulating gas circuit according to an embodiment of the present invention;
FIG. 8 is a schematic diagram illustrating the pressure profile within the drive tube during detonation in accordance with an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments and accompanying drawings.
As shown in fig. 1, in an embodiment of the present invention, an automatic inflation control system for detonation-driven high enthalpy shock tunnel is disclosed, which includes a shock tunnel 100, an air supply pipeline, a control air source and a control unit.
The shock tunnel 100 is used for carrying out high enthalpy tests of aircrafts, is of a pipeline-shaped structure, is internally and sequentially divided into an explosion unloading section 1, a driving section 2, a driven section 3, a spray pipe 4 and a test chamber 5, all the sections are separated by a diaphragm 6, and the diaphragm 6 can be broken by gas during detonation.
The driving section 2 needs to be filled with high-pressure gas capable of detonating in advance, the driven section 3 is filled with low-pressure driven gas, the explosion-discharging section 1 is vacuumized, each two sections are separated by a diaphragm 6, and the detonation mode is generally forward detonation or reverse detonation.
Taking the reverse detonation operation mode as an example, the operation wave system diagram generated by the detonation gas in the shock tunnel 100 is shown in fig. 2. An ignition pipe 21 for igniting gas in the driving section 2 is close to the diaphragm 6 between the driving section 2 and the driven section 3, after the diaphragm is ignited and broken, mixed gas in the driving section 2 is subjected to CJ detonation and then expanded through Taylor, high-pressure gas is generated to drive test gas in the driven section 3 to accelerate, and shock waves are transmitted towards the downstream nozzle 4. The contact surface co-propagates behind the shock wave. The 1 region of the shock tube becomes the 2 region after the compression of the incident shock. The central rarefaction wave at the position of the diaphragm 6 propagates to the upstream of the driving section 2 and has the opposite direction to the incident shock wave. The contact surface is a discontinuous surface with certain physical (such as temperature, density, sound velocity, entropy and the like) but meets the compatibility condition, and the pressure and the velocity are the same. The incident wave is reflected after being transmitted to the wall surface of the spray pipe 4, and the reflected wave secondarily compresses the gas in the area 2, so that the gas in the area 5 is obtained. The gas in the 5-zone is the gas after two times of compression and heating, and is high-temperature and high-pressure gas. The zone 5 gas is the chamber gas of the test chamber 5, and is expanded and accelerated through the nozzle 4 to obtain the required gas flow parameters of the test chamber 5.
The nozzle 4 comprises a contraction section and an expansion section, the contraction section is formed by contracting the connecting end of the driven section 3, the expansion section is in a horn mouth shape formed by arc expansion of the contraction section to the test cabin 5, wherein the minimum diameter of the contraction section is smaller than that of the driven section 3, and the maximum diameter of the expansion section is larger than that of the driven section 3.
As shown in fig. 3, the gas supply pipeline includes a plurality of gas sources, and delivery pipelines for delivering the gas sources respectively and connected to the driving section 2, and each delivery pipeline is provided with an electronic pressure regulator and a high-pressure pneumatic valve respectively;
in the embodiment, three gas sources are selected, namely hydrogen, oxygen and nitrogen. The connecting points of the conveying pipelines for respectively conveying hydrogen, oxygen and nitrogen and the driving section 2 are positioned on the same section of the pipe wall of the driving section 2, and the connecting points are symmetrically distributed. Namely, the connecting points of the hydrogen, the oxygen and the nitrogen with the driving section 2 are 120 degrees, and the three gas jet flows are firstly collided after being filled into the driving section 2, then are fully mixed and flow to other parts of the driving section 2.
The conveying pipeline is also provided with a filter for filtering impurities in the gas, a critical throat for preventing back pressure influence and a sonic nozzle connected with the driving section 2; the filter is positioned at the upstream of the electronic pressure regulator, the two ends of the filter are respectively provided with a stop valve and an electromagnetic valve, the critical throat is positioned between the electronic pressure regulator and the pressure regulating pneumatic valve, and a one-way valve is arranged between the critical throat and the electronic pressure regulator.
The control air source adopts the air source to be used for adjusting the gas pressure in the conveying pipeline, the control gas is conveyed through the control pipeline, the constant pressure reducers are respectively installed on the control pipelines, the stop valve and the filter are installed between the constant pressure reducers and the air source, and the control pipelines are respectively connected with the pressure regulating pneumatic valves on the conveying pipelines through the steering valves.
As shown in fig. 4, the control unit is a computer as a control end, and includes an NI control card connected to each electronic pressure regulator through a network cable, where the electronic pressure regulator stores a predetermined pressure value, the NI control card respectively obtains real-time pressure signals in the upstream and driving sections of each electronic pressure regulator, compares the real-time pressure signals with the predetermined pressure values in each electronic pressure regulator, adjusts the high-pressure pneumatic valves or constant-pressure reducers of the corresponding conveying pipelines and control sources according to the difference values until the pressure of each air source is balanced with the predetermined pressure value, and simultaneously inflates the driving sections, and stops the inflation of each air source after the mixed pressure of each air source in the driving sections reaches a specified requirement.
The critical throat pipe inflation principle adopted by the embodiment is that high-pressure airflow passes through the sonic nozzle and reaches the sonic velocity, the gas mass flow is kept constant, and the influence of back pressure generated at the downstream of the critical throat pipe is avoided.
The mixing pressure of each air source in the driving section 2 reaches the specified requirement: when the mixed gas generates a reflection shock wave during detonation and the contact surface interacts with each other, no reflection can be generated on the contact surface so as to meet the requirement of sewing the contact surface, wherein the conditions of sewing the contact surface are as follows:
in the formula, a4And a1Respectively representing sound velocities of different wave system regions generated after detonation, wherein Ms is an incident shock wave Mach number. a is4The velocity of sound after the detonation of the gas in the driving section is shown, and when the inflation proportion of the driving section 2 is inaccurate, the CJ pressure value and the gas velocity after the detonation are different, so that the stitching running state of the shock tunnel can be influenced. At a mixed charge ratio H2:O2:N22:1:1, initial pressure of charge P4 i-30 atm, respectively, and CJ pressure and a obtained after detonation when the charge ratio of hydrogen, oxygen and nitrogen fluctuates by 20% respectively4The fluctuation range is shown in fig. 5 and 6. It can be seen from fig. 5 and 6 that when the inflation pressure fluctuation causes the inflation proportion to change, the change of the gas sound velocity after detonation is more obvious than the change of the pressure value, so that the stitching operation state of the shock tunnel is influenced. In order to ensure the stability of the inflow parameters of the shock tunnel and the repeatability of the experimental results, the accuracy of the inflation proportion needs to be ensured in the inflation process.
Thus, the pressure of each gas source upstream of the electronic pressure regulator is determined in the following manner:
the mass flow of gas through the sonic nozzle is obtained by:
in the formula A*The area of the throat is shown as the area of the throat,
respectively, molecular weight, specific heat ratio, universal gas constant, p0,T0The total pressure and the total temperature of an outlet of the electronic pressure regulator are shown;
the mixing ratio of different gases is essentially the molar ratio of the gases, and if the mixing ratio of two gases in the mixed gas is n, the mixing ratio comprises the following components:
substituting equation (2) into equation (3) yields:
when the total temperature remains constant, i.e. (T)0)1≈(T0)2Then, the simplification is:
it is thus determined that the gas pressure upstream of the electronic pressure regulator needs to meet the requirements of equation (5). After the gas components are determined, the inflation proportion of different gases is related to the critical throat area and the pressure value of the upstream of the sonic nozzle, and the critical throat area cannot be changed after processing and forming, so that the pressure value of the upstream of the critical throat is the key for ensuring constant inflation mass flow in the whole inflation process. Traditional critical throat upper reaches pressure value realizes pressure adjustment through manual pressure reducer, need in time manual adjustment pressure value at whole inflation process, just can guarantee to inflate the pressure value of critical throat upper reaches and stabilize at certain extent in the process, and it can't do the accurate automatic control of this embodiment.
The electronic pressure regulator in the embodiment adopts ER5000, and the ER5000 is a PID controller based on a microprocessor, and can provide accurate algorithm pressure control for wide-range application. The ER5000 can be connected to a PC for control through a direct USB or RS485, and the pressure value can also be set through an external analog quantity. The control unit of the embodiment automatically controls the high-pressure pneumatic valves by using the ER5000 at the same time, monitors the pressures of the air source, the driving pipeline and the driving section, and controls the pressure of the air source at the same time.
In the embodiment, an NI control card is used as a control hardware system, and the voltage regulating value of the ER5000 is controlled through external analog quantity.
An eight-slot Ethernet chassis cDAQ is adopted as a control host on hardware, and the long-distance accurate synchronization is realized by automatically synchronizing the measurement data through the network time. An 8-channel independent analog output AO module is installed in the machine case clamping groove, and an analog output signal of 4-20 mA is accurately provided; inputting analog quantity of 16 channels into an AI module, and collecting air source and pressure regulating signals; and the 32-channel digital output DO module controls the action of an air source solenoid valve switch and a reversing valve of the high-pressure pneumatic valve. LabVIEW is adopted as programming software, the software has good interactivity with an NI control card, and meanwhile, a graphical operation interface and a data flow programming language are convenient for development and maintenance of a user program.
When the gas source device works, after the gas of hydrogen, oxygen and nitrogen passes through the stop valve and the filter, the remote electromagnetic valve opens the switch, the pressure of each gas source is adjusted to be required pressure through the electronic pressure regulator, then the gas is inflated into the driving section through the one-way valve and the critical throat pipe, and the valve is closed through the remote control high-pressure pneumatic valve after the inflation pressure is reached. The three sonic nozzles of hydrogen, oxygen and nitrogen are injected into the driving section at the position of 120 degrees, and then collide with each other, and flow to other parts after being mixed, thereby achieving the effect of uniform mixing. The high-pressure pneumatic valve adopts air as a control air source, and the air source controls the on-off of the pneumatic valve through the reversing valve after passing through the constant-pressure reducer.
The automatic pressure regulation can be divided into H according to the corresponding gas source2Pressure regulating gas circuit, O2Pressure regulating gas circuit and N2Three parts of pressure regulating gas circuit are basically similar in system control, and H is used2The pressure regulating gas circuit is taken as an example, and a specific control schematic diagram thereof is shown in fig. 7.
The ER5000 adopts a closed-loop control regulation mode, firstly writes a pressure regulation value (AO-1) needing to be set into the ER5000 through an AO module, then feeds back the regulated pressure value to an ER5000 controller through a pressure sensor, and the controller reads a feedback value once every 25ms and compares the feedback value with a set value. If the feedback value is below the set point, ER5000 will activate the intake valve, allowing the pilot pressure to enter the actuator of the electronic pressure regulator. This will cause the main valve of the electronic pressure regulator to open, thereby increasing the downstream system pressure. ER5000 will continue to deliver pilot pressure to the pneumatic actuator of the electronic pressure regulator until the feedback value and the set value are equal. If the feedback value is higher than the set value, ER5000 will activate the exhaust valve, releasing the pilot pressure from the electronic pressure regulator. The reduction in pilot pressure may cause the main valve of the electronic regulator to close while also causing the electronic regulator discharge port to open, thereby discharging excess system pressure, with the result that downstream system pressure is reduced, ER5000 will continue to discharge pilot pressure until the feedback signal equals the set point. When the two values are equal, the exhaust valve will close, and the system will be stabilized at this pressure. In the figure, AI-1 is the real-time pressure signal of the pressure sensor at the upstream of the electronic pressure regulator, and AI-2 is the real-time pressure signal of the pressure sensor in the driving section.
In order to ensure sufficient air source pressure supply and monitor the actual outlet pressure of the electronic pressure regulator, each pressure regulating air circuit control system carries out data acquisition on the air source pressure and the feedback pressure value through the AI module, so that the reliability of the inflation parameters is ensured.
Before the driving section 2 is inflated, firstly, the inflation parameters of each air supply pipeline are set, then, the electronic pressure regulator is started to regulate the pressure, and the inflation operation is started after the pressure of the electronic pressure regulator is stabilized. In the process of inflation, the DO module is controlled by a program to simultaneously open H2/O2/N2Three-way high-pressure pneumatic valveAnd then, starting inflation, reading the pressure value of a pressure sensor in the driving section 2 in real time, and closing three paths of high-pressure pneumatic valves simultaneously through a DO module after the inflation pressure reaches a preset value to complete the whole inflation process.
Because the remote pressure adjustment is carried out through the Ethernet, the electronic pressure regulator can be directly placed near the air charging port (sonic nozzle) of the driving section 2, so that the distance between the pressure-regulated gas and the critical throat can be very short, the pressure loss of the gas along the pipeline is reduced, and the accuracy of the air charging pressure is ensured.
According to the embodiment, the NI control card is controlled by Ethernet communication to input and output analog quantity and digital quantity, and a visual graphic operation interface is adopted, so that the remote accurate control of an electronic pressure regulator and the automatic on-off control of a high-pressure pneumatic valve are realized, and the danger in the detonation experiment process is eliminated; the remote accurate control and the whole-course inflation pressure monitoring function of the electronic pressure regulator are utilized to adjust the high-pressure pneumatic valve to carry out automatic on-off control, so that the inflation parameters in the test process are accurate and reliable, and the detonation operation result has good repeatability, therefore, the scheme has stable performance, accurate inflation parameters and good expansibility.
The effect achieved by the present solution is described below with a specific embodiment.
During the test, the test is carried out by adopting a shock tube mode, and the initial component of gas in the driving section is H2:O2:N22:1:3.762, initial pressure 20 atm; the low pressure section was air, the initial pressure was 33KPa, and the stitching run. The control unit of the scheme is utilized to carry out remote inflation operation, and after detonation is ignited, pressure signals measured by each pressure measuring point in the tube wall of the shock tunnel are shown in figure 8. CH1-CH4 are detonation-driven high-pressure sections, CH6-CH8 are driven sections, ignition is carried out between 4 and 6, and it can be seen from the pressure jump time of CH4 and CH3 that after ignition, initial detonation is generated in the high-pressure sections immediately, the detonation speed is 2089m/s, the detonation wave speed calculated according to CJ detonation theory is 2033m/s, and the detonation wave speed are basically consistent, so that the scheme can be used for controlling the proportion parameters of the charged fuel gas to be correct and the gas to be uniformly mixed.
Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.
Claims (9)
1. The utility model provides a detonation drive high enthalpy shock tunnel automatic inflation control system which characterized in that includes:
the shock tunnel is used for carrying out a high enthalpy test and is sequentially divided into an explosion unloading section, a driving section, a driven section, a spray pipe and a test chamber;
the air supply pipeline comprises a plurality of air sources and conveying pipelines which respectively convey the air sources and are connected with the driving section, and an electronic pressure regulator and a high-pressure pneumatic valve are respectively arranged on each conveying pipeline;
the control air source comprises an air source and a control pipeline for connecting the air source with each high-pressure pneumatic valve, and a constant-pressure reducer is arranged on the control pipeline;
and the control unit comprises an NI control card connected with each electronic pressure regulator through a network cable, preset pressure values are stored in the electronic pressure regulators, the NI control card respectively acquires real-time pressure signals at the upper streams of the electronic pressure regulators and in the driving section, then the real-time pressure signals are compared with the preset pressure values in the electronic pressure regulators, corresponding high-pressure pneumatic valves or constant-pressure reducers are adjusted according to difference values until the pressure of each gas source is balanced with the preset pressure values, then the driving section is simultaneously inflated, and the inflation of each gas source is stopped after the mixed pressure of each gas source in the driving section reaches the specified requirement.
2. The automatic inflation control system of claim 1,
the conveying pipeline is also provided with a filter for filtering impurities in the gas, a critical throat for preventing back pressure influence, a sonic nozzle connected with the driving section and on-off valves arranged at the control parts.
3. The automatic inflation control system of claim 1,
the spray pipe comprises a contraction section and an expansion section, the contraction section is formed by contracting the connecting end of the driven section, the expansion section is in a horn mouth shape formed by expanding the contraction section towards the test cabin, the minimum diameter of the contraction section is smaller than the diameter of the driven section, and the maximum diameter of the expansion section is larger than the diameter of the driven section.
4. The automatic inflation control system of claim 1,
the NI control card comprises an AO module for outputting analog quantity, an AI module for inputting analog quantity and a DO module for outputting digital signals.
5. The automatic inflation control system of claim 1,
the connection points of the conveying pipelines of the air supply pipeline and the driving section are positioned on the same cross section, and the connection points are symmetrically distributed.
6. The automatic inflation control system of claim 5,
the gas source comprises hydrogen, oxygen and nitrogen.
7. The automatic inflation control system of claim 6,
the connecting points of the hydrogen, oxygen and nitrogen and the driving section are 120 degrees, the three gas jet flows are filled into the driving section and then collide with each other, and then the full mixing is realized.
8. The automatic inflation control system of claim 1,
the mixed pressure of each air source in the driving section meeting the specified requirement means that: when the mixed gas generates a reflection shock wave during detonation and the contact surface interacts with each other, no reflection can be generated on the contact surface so as to meet the requirement of sewing the contact surface, wherein the conditions of sewing the contact surface are as follows:
in the formula, a4And a1Respectively representing sound velocities of different wave system regions generated after detonation, wherein Ms is an incident shock wave Mach number.
9. The automatic inflation control system of claim 8,
the pressure of the air source upstream of the electronic pressure regulator is determined in the following manner:
the mass flow of gas through the sonic nozzle is obtained by:
in the formula A*The area of the throat is shown as the area of the throat,
respectively, molecular weight, specific heat ratio, universal gas constant, p0,T0The total pressure and the total temperature of an outlet of the electronic pressure regulator are shown;
the mixing ratio of different gases is essentially the molar ratio of the gases, and if the mixing ratio of two gases in the mixed gas is n, the mixing ratio comprises the following components:
substituting equation (2) into equation (3) yields:
when the total temperature is kept constantWhen is (T)0)1≈(T0)2Then, the simplification is:
it is thus determined that the gas pressure upstream of the electronic pressure regulator needs to meet the requirements of equation (5).
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113074898A (en) * | 2021-04-06 | 2021-07-06 | 中国空气动力研究与发展中心超高速空气动力研究所 | Premixing air supply device for shock tube and premixing air supply method thereof |
| CN113094908A (en) * | 2021-04-16 | 2021-07-09 | 中国石油大学(华东) | Combustible gas pipeline explosion intensity deduction method based on section trace measurement |
| CN113375889A (en) * | 2021-05-14 | 2021-09-10 | 中国科学院力学研究所 | Thermal jet flow experimental method for shock tunnel |
| CN113375890A (en) * | 2021-05-14 | 2021-09-10 | 中国科学院力学研究所 | Thermal jet flow experimental device for shock tunnel |
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| CN114414626A (en) * | 2022-01-21 | 2022-04-29 | 安徽理工大学 | Combustible gas detonation drive generator for high-speed loading |
| CN114414194A (en) * | 2021-09-07 | 2022-04-29 | 中国空气动力研究与发展中心空天技术研究所 | Parameter adjusting device and method for hypersonic-speed variable Mach number wind tunnel |
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| CN118008917A (en) * | 2024-03-28 | 2024-05-10 | 中国航空工业集团公司沈阳空气动力研究所 | Control device and method for pipe wind tunnel driving piston |
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| CN113074898A (en) * | 2021-04-06 | 2021-07-06 | 中国空气动力研究与发展中心超高速空气动力研究所 | Premixing air supply device for shock tube and premixing air supply method thereof |
| CN113094908A (en) * | 2021-04-16 | 2021-07-09 | 中国石油大学(华东) | Combustible gas pipeline explosion intensity deduction method based on section trace measurement |
| CN113375889A (en) * | 2021-05-14 | 2021-09-10 | 中国科学院力学研究所 | Thermal jet flow experimental method for shock tunnel |
| CN113375890A (en) * | 2021-05-14 | 2021-09-10 | 中国科学院力学研究所 | Thermal jet flow experimental device for shock tunnel |
| CN114414194A (en) * | 2021-09-07 | 2022-04-29 | 中国空气动力研究与发展中心空天技术研究所 | Parameter adjusting device and method for hypersonic-speed variable Mach number wind tunnel |
| CN114414194B (en) * | 2021-09-07 | 2024-05-28 | 中国空气动力研究与发展中心空天技术研究所 | Parameter adjusting device and method for high-ultrasonic speed variable Mach number wind tunnel |
| CN113933347A (en) * | 2021-09-22 | 2022-01-14 | 北京科技大学 | Detonation experiment system and method based on virtual instrument |
| CN114414626A (en) * | 2022-01-21 | 2022-04-29 | 安徽理工大学 | Combustible gas detonation drive generator for high-speed loading |
| CN114414626B (en) * | 2022-01-21 | 2023-11-03 | 安徽理工大学 | Combustible gas detonation drive generator for high-speed loading |
| CN115327892A (en) * | 2022-10-12 | 2022-11-11 | 中国航空工业集团公司沈阳空气动力研究所 | Combined high-enthalpy wind tunnel multi-path high-pressure air supply control system and method |
| CN118008917A (en) * | 2024-03-28 | 2024-05-10 | 中国航空工业集团公司沈阳空气动力研究所 | Control device and method for pipe wind tunnel driving piston |
| CN118008917B (en) * | 2024-03-28 | 2024-06-04 | 中国航空工业集团公司沈阳空气动力研究所 | Control device and method for pipe wind tunnel driving piston |
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