Test device and test method for mitigating nozzle throat ablation in high enthalpy pulsed wind tunnel

Abstract

The present invention belongs to the field of wind tunnel testing and discloses a test device and test method for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion. The test device is provided with an electromagnetic deceleration channel in the contraction section of the nozzle body and an electromagnetic acceleration channel in the expansion section. The electromagnetic deceleration channel and the electromagnetic acceleration channel are respectively connected to a pulse power supply system, and the pulse power supply system is connected to a control system. The test method includes setting test parameters; opening and closing the electromagnetic deceleration channel and the electromagnetic acceleration channel. The test device and the test method extract the high-enthalpy airflow energy generated at the end of the low-pressure section of the wind tunnel through the electromagnetic deceleration channel, reduce the airflow temperature, alleviate nozzle throat erosion, and reduce the difficulty of designing the nozzle throat heat protection structure. Kinetic energy is directly added to the gas through the electromagnetic acceleration channel to increase the airflow velocity, and different airflow Mach numbers are obtained by using different electric field and magnetic field control parameters. The test device and the test method have high test efficiency, are easy to use, and have practical engineering value.

Description

Technical Field

[0001] The present invention belongs to the technical field of ramjet engines, and in particular relates to a test device and a test method for alleviating high enthalpy pulse wind tunnel nozzle throat ablation. Background Art

[0002] In the aerospace field, pulse wind tunnels are essential equipment for reproducing hypersonic flight environments and conducting aerodynamic and aero-thermal tests. With the development of hypersonic flight technology, the increasingly extreme flight environments require pulse wind tunnels to conduct a large number of high-enthalpy simulation state tests. However, nozzle throat ablation is one of the key issues that limits the ability of pulse wind tunnels to conduct high-enthalpy simulation state tests.

[0003] Under high-enthalpy simulation conditions, the airflow in the nozzle is hot and fast, accompanied by strong shock wave-turbulent boundary layer interactions. This results in extremely high heat flux density on the surface of the nozzle throat material, which is prone to high-temperature ablation. At the same time, the ablation products of the material will also mechanically scour the throat surface, causing throat damage and significantly affecting the flow field quality. Currently, ablation is mainly alleviated through material improvements and cooling technologies, including the use of higher melting point materials, throat surface coatings, embedding water-cooling or air-cooling channels inside the throat, and replacing the throat lining. However, there are problems such as material limitations, easy peeling of coatings, complex cooling structures, and reduced test efficiency.

[0004] Currently, there is an urgent need to develop a test device and test method to alleviate the throat erosion of high-enthalpy pulse wind tunnel nozzles. Summary of the Invention

[0005] One technical problem to be solved by the present invention is to provide a test device for alleviating high enthalpy pulse wind tunnel nozzle throat erosion. Another technical problem to be solved is to provide a test method for alleviating high enthalpy pulse wind tunnel nozzle throat erosion, so as to overcome the defects of the prior art.

[0006] The experimental device for alleviating high enthalpy pulse wind tunnel nozzle throat ablation of the present invention is provided with an electromagnetic deceleration channel at the contraction section of the nozzle body. The length of the electromagnetic deceleration channel is l , an electromagnetic acceleration channel is set in the expansion section of the nozzle body, and the length of the electromagnetic acceleration channel is n The electromagnetic deceleration channel and the electromagnetic acceleration channel are respectively connected to the pulse power supply system, and the pulse power supply system is connected to the control system;

[0007] The electromagnetic deceleration channel includes L groups of electrode pairs I uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the contraction section. The electrode spacing of the electrode pair I is x 1. The electrode width is y1. The upper side is the electrode anode, and the lower side is the electrode cathode. Each group of electrode pairs I forms a closed loop, and a non-inductive resistor is set on the closed loop; rectangular electromagnets I are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel, with the left side being the electromagnet's N pole and the right side being the electromagnet's S pole. The magnetic field strength is controlled in real time according to the coil current;

[0008] The electromagnetic acceleration channel includes M groups of electrode pairs II uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the expansion section. The electrode spacing of the electrode pair II is x 2. The electrode width is y 2. The upper side is the electrode cathode, and the lower side is the electrode anode. Each group of electrode pairs II forms a closed loop. A non-inductive resistor is also set on the closed loop. The electric field strength is controlled in real time according to the current size. Rectangular electromagnets II are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel. The left side is the electromagnet N pole and the right side is the electromagnet S pole. The magnetic field strength is controlled in real time according to the coil current size.

[0009] Furthermore, the electromagnetic deceleration channel and the electromagnetic acceleration channel are both segmented Faraday channels.

[0010] Furthermore, the material of the nozzle body is 35CrNi3MoVR.

[0011] Furthermore, the anode material of the electrode pair I and the electrode pair II is a molybdenum alloy, and the cathode material is a hafnium alloy.

[0012] Furthermore, the rectangular electromagnet I and the rectangular electromagnet II are iron core coils with a maximum magnetic flux density ≥3T.

[0013] Furthermore, insulating layers are provided on both sides of the electrode pair I and the electrode pair II to achieve insulation from the inner wall of the nozzle body.

[0014] Furthermore, the pulse power supply system adopts grouped capacitors for charging and discharging.

[0015] The test method for alleviating high enthalpy pulse wind tunnel nozzle throat ablation of the present invention comprises the following steps:

[0016] S10. Set test parameters;

[0017] Before the test, the current required for the electromagnetic deceleration channel and the electromagnetic acceleration channel is calculated according to different test conditions. Based on the current, the control system sets the test parameters, including the trigger signal, current and power-on time corresponding to the rectangular electromagnet I, the electrode pair II and the rectangular electromagnet II.

[0018] S20. Open the electromagnetic deceleration channel and the electromagnetic acceleration channel;

[0019] During the test, at time t1, the shock tube membrane of the pulse wind tunnel ruptured. The membrane rupture signal served as a trigger to activate the test device for mitigating high-enthalpy pulse wind tunnel nozzle throat erosion. A constant current was supplied to the rectangular electromagnet I, opening the electromagnetic deceleration channel. At time t2, the shock wave reached the downstream end of the low-pressure section, generating a high-temperature, high-pressure conductive airflow that entered the nozzle throat. The electromagnetic deceleration channel extracted the high-enthalpy airflow energy, converted it into electrical energy, and output it to the capacitor storage of the pulse power system.

[0020] At the same time t1, the electrode pairs II are powered in groups, and the rectangular electromagnet II is powered with a constant current, turning on the electromagnetic acceleration channel. At t3, the airflow is accelerated through the electromagnetic acceleration channel, and then further accelerated and homogenized by the nozzle before reaching the nozzle outlet, forming a test flow field.

[0021] S30. Close the electromagnetic deceleration channel and the electromagnetic acceleration channel;

[0022] After the test, the electromagnetic deceleration channel and the electromagnetic acceleration channel are closed and the test ends.

[0023] The test device and test method for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion of the present invention utilize the high temperature and high conductivity characteristics of the airflow at the end of the low-pressure section after shock wave compression to achieve direct control of the airflow through electromagnetic acceleration and deceleration technology. Among them, the high-enthalpy airflow energy generated at the end of the low-pressure section of the wind tunnel is extracted through the electromagnetic deceleration channel to reduce the airflow temperature, alleviate the nozzle throat erosion, and reduce the difficulty of the nozzle throat heat protection structure design. Kinetic energy is directly added to the gas through the electromagnetic acceleration channel to increase the airflow speed. Different electric field and magnetic field control parameters are used to obtain different airflow Mach numbers. The test device and test method for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion of the present invention can make the high-enthalpy airflow bypass the nozzle throat in the form of electrical energy, realize upstream and downstream high-enthalpy airflow energy transmission, have high test efficiency, are easy to use, and have practical engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the test device for alleviating high-enthalpy pulse wind tunnel nozzle throat ablation according to the present invention (xz section);

[0025] Figure 2 This is a schematic structural diagram (xy cross-section) of the experimental device for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion according to the present invention.

[0026] In the figure, 1. electromagnetic deceleration channel; 2. rectangular electromagnet I; 3. electromagnetic acceleration channel; 4. rectangular electromagnet II; 5. nozzle body; 6. pulse power supply system; 7. control system; 8. electrode pair I; 9. insulation layer; 10. non-inductive resistor; 11. capacitor; 12. electrode pair II. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 、 Figure 2 As shown in the figure, the experimental device for alleviating high enthalpy pulse wind tunnel nozzle throat erosion of the present invention is provided with an electromagnetic deceleration channel 1 at the contraction section of the nozzle body 5. The length of the electromagnetic deceleration channel 1 is l , an electromagnetic acceleration channel 3 is set in the expansion section of the nozzle body 5, and the length of the electromagnetic acceleration channel 3 is n The electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3 are respectively connected to the pulse power supply system 6, and the pulse power supply system 6 is connected to the control system 7;

[0029] The electromagnetic deceleration channel 1 includes L groups of electrode pairs Ⅰ8 uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the contraction section. The electrode spacing of the electrode pair Ⅰ8 is x 1. The electrode width is y 1. The upper side is the electrode anode, and the lower side is the electrode cathode. Each group of electrode pairs Ⅰ8 forms a closed loop, and a non-inductive resistor 10 is set on the closed loop. Rectangular electromagnets Ⅰ2 are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel 1, with the left side being the electromagnet's N pole and the right side being the electromagnet's S pole. The magnetic field strength is controlled in real time according to the coil current.

[0030] The electromagnetic acceleration channel 3 includes M groups of electrode pairs II12 uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the expansion section. The electrode spacing of the electrode pair II12 is x 2. The electrode width is y 2, the upper side is the electrode cathode, the lower side is the electrode anode, each group of electrode pairs II 12 forms a closed loop, and a non-inductive resistor 10 is also set on the closed loop. The electric field strength is controlled in real time according to the current size; rectangular electromagnets II 4 are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel 3, with the left side being the electromagnet N pole and the right side being the electromagnet S pole. The magnetic field strength is controlled in real time according to the coil current size.

[0031] Furthermore, the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3 are both segmented Faraday channels.

[0032] Furthermore, the material of the nozzle body 5 is 35CrNi3MoVR.

[0033] Furthermore, the anode material of the electrode pair I8 and the electrode pair II12 is a molybdenum alloy, and the cathode material is a hafnium alloy.

[0034] Furthermore, the rectangular electromagnet I2 and the rectangular electromagnet II4 are iron core coils with a maximum magnetic flux density ≥3T.

[0035] Furthermore, insulating layers 9 are provided on both sides of the electrode pair I8 and the electrode pair II12 to achieve insulation from the inner wall of the nozzle body 5 .

[0036] Furthermore, the pulse power supply system 6 uses grouped capacitors 11 for charging and discharging.

[0037] The test method for alleviating high enthalpy pulse wind tunnel nozzle throat ablation of the present invention comprises the following steps:

[0038] S10. Set test parameters;

[0039] Before the test, the current required by the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3 is calculated according to different test conditions; according to the current, the control system 7 sets the test parameters, which include the trigger signal, current and power-on time corresponding to the rectangular electromagnet I2, the electrode pair II12 and the rectangular electromagnet II4;

[0040] S20. Open electromagnetic deceleration channel 1 and electromagnetic acceleration channel 3;

[0041] During the experiment, at time t1, the membrane of the pulse wind tunnel shock tube ruptured. The membrane rupture signal served as a trigger to activate the experimental device for mitigating high-enthalpy pulse wind tunnel nozzle throat erosion. A constant current was supplied to the rectangular electromagnet I2, opening the electromagnetic deceleration channel 1. At time t2, the shock wave reached the downstream end of the low-pressure section, generating a high-temperature, high-pressure conductive airflow that entered the nozzle throat. The electromagnetic deceleration channel 1 extracted the high-enthalpy airflow energy, converted it into electrical energy, and output it to the capacitor 11 of the pulse power supply system 6 for storage.

[0042] At the same time as t1, the electrode pairs II12 are powered in groups, the rectangular electromagnet II4 is powered with a constant current, and the electromagnetic acceleration channel 3 is turned on. At t3, the airflow is accelerated through the electromagnetic acceleration channel 3, and then further accelerated and homogenized by the nozzle before reaching the nozzle outlet, forming a test flow field.

[0043] S30. Close electromagnetic deceleration channel 1 and electromagnetic acceleration channel 3;

[0044] After the test, the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3 are closed, and the test ends.

[0045] Example: This example simulates a high-enthalpy pulse wind tunnel operating state at a high Mach number, with a Mach number of 12, an air flow medium of air, and a total temperature of ≥8000K; the nozzle body 5 is 2.2 m long and made of 35CrNi3MoVR.

[0046] Length of electromagnetic deceleration channel 1 l =1m, there are 25 groups of electrode pairs I8L, the electrode spacing of electrode pairs I8 is 30mm, and the electrode width is 10mm; each group of electrode pairs I8 forms a closed loop; rectangular electromagnets I2 are symmetrically arranged on the left and right sides, and the rectangular electromagnets I2 use iron core coils. The magnetic field strength is controlled by the coil current, and the strength range is 0~3T.

[0047] Length of electromagnetic acceleration channel 3 n =1m, and there are also 25 groups of electrode pairs II12M. Similarly, the electrode spacing of electrode pairs II12 is 30mm and the electrode width is 10mm. Each group of electrode pairs II12 forms a closed loop, and rectangular electromagnets II4 are symmetrically arranged on the left and right sides. The rectangular electromagnet II4 uses an iron core coil, and the magnetic field strength is controlled by the coil current, and the strength range is 0~3T.

[0048] The resistance of the non-inductive resistor 10 in each loop is 2Ω; the pulse power supply system 6 is powered by grouped capacitors 11, and the charging voltage of each group of capacitors 11 is 0~400V.

[0049] Under the action of load voltage, the electric field vector E and current vector J , current vector J With the magnetic field vector B The interaction induces the Lorentz volume force J × B .

[0050] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the description and implementation methods. For those familiar with the art, all features disclosed in the present invention, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion, characterized by: The test device for alleviating high enthalpy pulse wind tunnel nozzle throat erosion is provided with an electromagnetic deceleration channel (1) at the contraction section of the nozzle body (5). The length of the electromagnetic deceleration channel (1) is l An electromagnetic acceleration channel (3) is provided in the expansion section of the nozzle body (5), and the length of the electromagnetic acceleration channel (3) is n The electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3) are respectively connected to the pulse power supply system (6), and the pulse power supply system (6) is connected to the control system (7); The electromagnetic deceleration channel (1) includes L groups of electrode pairs I (8) uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the contraction section. The electrode spacing of the electrode pair I (8) is x 1. The electrode width is y 1, the upper side is the electrode anode, the lower side is the electrode cathode, each group of electrode pairs I (8) forms a closed loop, and a non-inductive resistor (10) is set on the closed loop; rectangular electromagnets I (2) are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel (1), the left side is the electromagnet N pole, and the right side is the electromagnet S pole. The magnetic field strength is controlled in real time according to the coil current; The electromagnetic acceleration channel (3) includes M groups of electrode pairs II (12) uniformly distributed along the axial direction on the inner wall surfaces of the upper and lower sides of the expansion section, and the electrode spacing of the electrode pair II (12) is x 2. The electrode width is y 2, the upper side is the electrode cathode, the lower side is the electrode anode, each group of electrode pairs II (12) forms a closed loop, and a non-inductive resistor (10) is also set on the closed loop. The electric field strength is controlled in real time according to the current size; rectangular electromagnets II (4) are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel (3), with the left side being the electromagnet N pole and the right side being the electromagnet S pole. The magnetic field strength is controlled in real time according to the coil current size.

2. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1 is characterized in that: The electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3) are both segmented Faraday channels.

3. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1, characterized in that: The material of the nozzle body (5) is 35CrNi3MoVR.

4. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1, characterized in that: The anode material of the electrode pair I (8) and the electrode pair II (12) is a molybdenum alloy, and the cathode material is a hafnium alloy.

5. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1, characterized in that: The rectangular electromagnet I (2) and the rectangular electromagnet II (4) are iron core coils with a maximum magnetic flux density of ≥3T.

6. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1, characterized in that: Insulating layers (9) are provided on both sides of the electrode pair I (8) and the electrode pair II (12) to achieve insulation from the inner wall of the nozzle body (5).

7. The test device for mitigating high enthalpy pulse wind tunnel nozzle throat erosion according to claim 1, characterized in that: The pulse power supply system (6) uses grouped capacitors (11) for charging and discharging.

8. A test method for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion, which is used in the test device for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S10. Set test parameters; Before the test, the current required by the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3) is calculated according to different test conditions; according to the current, the control system (7) sets the test parameters, which include the trigger signal, current and power-on time corresponding to the rectangular electromagnet I (2), the electrode pair II (12) and the rectangular electromagnet II (4); S20. Open the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3); During the test, at time t1, the membrane of the pulse wind tunnel shock tube ruptures, and the membrane rupture signal is used as a trigger signal to start the test device for alleviating high-enthalpy pulse wind tunnel nozzle throat erosion, supplying constant current to the rectangular electromagnet I (2), and opening the electromagnetic deceleration channel (1); at time t2, the shock wave reaches the downstream end of the low-pressure section to generate a high-temperature and high-pressure conductive airflow, which enters the nozzle throat, and the electromagnetic deceleration channel (1) extracts the high-enthalpy airflow energy, converts it into electrical energy, and outputs it to the capacitor (11) of the pulse power supply system (6) for storage; At the same time t1, the electrode pairs II (12) are powered in groups, the rectangular electromagnet II (4) is powered with a constant current, and the electromagnetic acceleration channel (3) is turned on; at t3, the airflow is accelerated through the electromagnetic acceleration channel (3), and then further accelerated and homogenized by the nozzle before reaching the nozzle outlet, forming a test flow field; S30. Close the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3); After the test, the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3) are closed, and the test ends.

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