Testing device for relieving ablation of high-enthalpy pulse wind tunnel nozzle throat and testing method thereof

Abstract

The invention belongs to the field of wind tunnel tests, and discloses a test device for relieving ablation of a high-enthalpy pulse wind tunnel nozzle throat and a test method thereof. According to the test device, an electromagnetic deceleration channel is arranged on a contraction section of a nozzle body, an electromagnetic acceleration channel is arranged on an expansion section, the electromagnetic deceleration channel and the electromagnetic acceleration channel are respectively connected with a pulse power supply system, and the pulse power supply system is connected with a control system. The test method comprises the steps of setting test parameters; and opening and closing the electromagnetic deceleration channel and the electromagnetic acceleration channel. According to the test device and the test method, high-enthalpy airflow energy generated at the tail end of the low-pressure section of the wind tunnel is extracted through the electromagnetic deceleration channel, the airflow temperature is reduced, nozzle throat ablation is relieved, and the design difficulty of a nozzle throat heat-proof structure is reduced. Kinetic energy is directly added to gas through the electromagnetic acceleration channel, the gas flow speed is increased, and different gas flow Mach numbers are obtained through different electric field and magnetic field control parameters. The test device and the test method thereof are high in test efficiency and convenient to use, and have engineering practical value.

Description

Technical Field

[0001] The invention belongs to the technical field of ramjet engines, and particularly relates to a test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel and a test method thereof. Background Technique

[0002] In the field of aerospace, pulsed wind tunnels are the main equipment for reproducing hypersonic flight environments and conducting aerodynamic and aerothermal tests. With the development of hypersonic flight technology, more extreme flight environments require a large number of high-enthalpy simulation state tests to be carried out in pulsed wind tunnels, and nozzle throat ablation is one of the key problems restricting the high-enthalpy simulation state tests in pulsed wind tunnels.

[0003] Under high-enthalpy simulation conditions, the gas flow in the nozzle has a high temperature and fast speed, and is accompanied by strong shock-turbulent boundary layer interactions, resulting 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 cause mechanical erosion to the throat surface, causing throat damage and having a greater impact on the flow field quality. At present, ablation is mainly alleviated through material improvement and cooling technologies, including using materials with higher melting points or applying coatings on the throat surface, embedding water-cooled or air-cooled 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 affecting test efficiency.

[0004] Currently, there is an urgent need to develop a test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel and a test method thereof. Summary of the Invention

[0005] One technical problem to be solved by the present invention is to provide a test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel, and another technical problem to be solved is to provide a test method for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel to overcome the defects of the prior art.

[0006] The test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to the present invention is provided with an electromagnetic deceleration channel in the contraction section of the nozzle body, and the length of the electromagnetic deceleration channel is l and an electromagnetic acceleration channel is provided 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 a pulsed power supply system, and the pulsed power supply system is connected to a control system; The electromagnetic deceleration channel includes L groups of electrode pairs Ⅰ uniformly distributed along the axial direction on the inner wall surfaces on both sides of the contraction section, and the electrode spacing of the electrode pairs Ⅰ is x 1, and 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 circuit, and a non-inductive resistor is arranged on the closed-loop circuit. Rectangular electromagnets Ⅰ are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel. The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field intensity is controlled in real time according to the magnitude of the coil current. The electromagnetic acceleration channel includes M groups of electrode pairs Ⅱ uniformly distributed along the axial direction on the inner wall surfaces on the upper and lower sides of the expansion section. The electrode spacing of the electrode pairs 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 circuit, and a non-inductive resistor is also arranged on the closed-loop circuit. The electric field intensity is controlled in real time according to the magnitude of the current. Rectangular electromagnets Ⅱ are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel. The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field intensity is controlled in real time according to the magnitude of the coil current.

[0007] Furthermore, both the electromagnetic deceleration channel and the electromagnetic acceleration channel are segmented Faraday-type channels.

[0008] Furthermore, the material of the nozzle body is 35CrNi3MoVR.

[0009] Furthermore, the anode material of the electrode pairs Ⅰ and electrode pairs Ⅱ is molybdenum alloy, and the cathode material is hafnium alloy.

[0010] Furthermore, the rectangular electromagnets Ⅰ and rectangular electromagnets Ⅱ are iron-core coils, and the maximum magnetic flux density ≥ 3T.

[0011] Furthermore, insulating layers are arranged on both sides of the electrode pairs Ⅰ and electrode pairs Ⅱ to achieve insulation from the inner wall of the nozzle body.

[0012] Furthermore, the pulse power supply system uses grouped capacitors for charging and discharging.

[0013] The test method for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to the present invention includes the following steps: S10. Set test parameters; Before the test, according to different test conditions, calculate the magnitudes of the currents required for the electromagnetic deceleration channel and the electromagnetic acceleration channel; according to the magnitudes of the currents, the control system sets the test parameters, and the test parameters include the trigger signals, current magnitudes, and energization times corresponding to the rectangular electromagnets Ⅰ, electrode pairs Ⅱ, and rectangular electromagnets Ⅱ; S20. Turn on the electromagnetic deceleration channel and the electromagnetic acceleration channel; During the experiment, at time t1, the diaphragm of the shock tube in the pulsed wind tunnel ruptured, and the rupture signal was used as the trigger signal to start the experimental device for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel. A constant current was supplied to the rectangular electromagnet I, and the electromagnetic deceleration channel was opened; at time t2, the shock wave reached the downstream end of the low-pressure section, generating a high-temperature and high-pressure conductive gas flow, which entered the nozzle throat. The energy of the high-enthalpy gas flow was extracted by the electromagnetic deceleration channel and converted into electrical energy and output to the capacitor of the pulsed power supply system for storage; At the same time as t1, the electrode pair II was grouped for power supply, a constant current was supplied to the rectangular electromagnet II, and the electromagnetic acceleration channel was opened; at time t3, the gas flow was accelerated through the electromagnetic acceleration channel, and then continued to be accelerated and homogenized by the nozzle and reached the nozzle outlet to form an experimental flow field; S30. Close the electromagnetic deceleration channel and the electromagnetic acceleration channel; After the experiment, the electromagnetic deceleration channel and the electromagnetic acceleration channel were closed, and the experiment ended.

[0014] The experimental device and method for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel of the present invention utilize the characteristics of high temperature and high electrical conductivity of the gas flow at the downstream end of the low-pressure section after shock wave compression, and directly control the gas flow through electromagnetic acceleration and deceleration technologies. Among them, the energy of the high-enthalpy gas flow generated at the downstream end of the low-pressure section of the wind tunnel is extracted through the electromagnetic deceleration channel, the gas flow temperature is reduced, the ablation of the nozzle throat is alleviated, and the design difficulty of the nozzle throat thermal protection structure is reduced. The kinetic energy is directly added to the gas through the electromagnetic acceleration channel to increase the gas flow velocity, and different gas flow Mach numbers are obtained by using different electric and magnetic field control parameters. The experimental device and method for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel of the present invention can make the high-enthalpy gas flow bypass the nozzle throat in the form of electrical energy, realize the energy transmission of the high-enthalpy gas flow upstream and downstream, have high experimental efficiency and are easy to use, and have engineering practical value. Brief Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram (xz section) of the experimental device for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel of the present invention; Figure 2 It is a schematic structural diagram (xy section) of the experimental device for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel of the present invention.

[0016] In the figure, 1. Electromagnetic deceleration channel; 2. Rectangular electromagnet I; 3. Electromagnetic acceleration channel; 4. Rectangular electromagnet II; 5. Nozzle body; 6. Pulsed power supply system; 7. Control system; 8. Electrode pair I; 9. Insulating layer; 10. Non-inductive resistor; 11. Capacitor; 12. Electrode pair II. Detailed Embodiment

[0017] The present invention will be described in detail below with reference to the drawings and embodiments.

[0018] As Figure 1 、Figure 2 As shown, the test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel sets an electromagnetic deceleration channel 1 in the contraction section of the nozzle body 5. The length of the electromagnetic deceleration channel 1 is l , and an electromagnetic acceleration channel 3 is set in the expansion section of the nozzle body 5. 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 a pulsed power supply system 6, and the pulsed power supply system 6 is connected to a 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 on both the upper and lower sides of the contraction section. The electrode spacing of the electrode pairs I 8 is x 1, and 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 I 8 forms a closed-loop circuit, and a non-inductive resistor 10 is set on the closed-loop circuit; rectangular electromagnets I 2 are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel 1. The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field intensity is controlled in real time according to the magnitude of 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 on both the upper and lower sides of the expansion section. The electrode spacing of the electrode pairs II 12 is x 2, and 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 12 forms a closed-loop circuit, and a non-inductive resistor 10 is also set on the closed-loop circuit. The electric field intensity is controlled in real time according to the magnitude of the current; rectangular electromagnets II 4 are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel 3. The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field intensity is controlled in real time according to the magnitude of the coil current.

[0019] Furthermore, both the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3 are segmented Faraday-type channels.

[0020] Furthermore, the material of the nozzle body 5 is 35CrNi3MoVR.

[0021] Furthermore, the anode material of the electrode pairs I 8 and the electrode pairs II 12 is molybdenum alloy, and the cathode material is hafnium alloy.

[0022] Furthermore, the rectangular electromagnets I 2 and the rectangular electromagnets II 4 are iron-core coils, and the maximum magnetic flux density ≥ 3T.

[0023] Furthermore, insulating layers 9 are arranged on both sides of the electrode pairs I 8 and the electrode pairs II 12 to achieve insulation from the inner wall of the nozzle body 5.

[0024] Furthermore, the pulsed power supply system 6 uses grouped capacitors 11 for charging and discharging.

[0025] The experimental method for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to the present invention includes the following steps: S10. Set the experimental parameters; Before the experiment, according to different experimental conditions, calculate the current magnitudes required for the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3; according to the current magnitudes, the control system 7 sets the experimental parameters, and the experimental parameters include the trigger signals, current magnitudes, and energization times corresponding to the rectangular electromagnet I 2, the electrode pair II 12, and the rectangular electromagnet II 4; S20. Turn on the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3; During the experiment, at time t1, the diaphragm of the shock tube of the pulsed wind tunnel bursts, and the experimental device for alleviating the ablation of the nozzle throat of the high-enthalpy pulsed wind tunnel is started with the bursting signal as the trigger signal, and a constant current is supplied to the rectangular electromagnet I 2 to turn on the electromagnetic deceleration channel 1; at time t2, the shock wave runs to the downstream end of the low-pressure section to generate a high-temperature and high-pressure conductive gas flow, which enters the nozzle throat. The electromagnetic deceleration channel 1 extracts the energy of the high-enthalpy gas flow and converts it into electric energy and outputs it to the capacitor 11 of the pulsed power supply system 6 for storage; At the same time as t1, the electrode pair II 12 is grouped for power supply, and a constant current is supplied to the rectangular electromagnet II 4 to turn on the electromagnetic acceleration channel 3; at time t3, the gas flow is accelerated through the electromagnetic acceleration channel 3, and then continues to be accelerated and homogenized by the nozzle and reaches the nozzle outlet to form an experimental flow field; S30. Turn off the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3; After the experiment, turn off the electromagnetic deceleration channel 1 and the electromagnetic acceleration channel 3, and the experiment ends.

[0026] Example: This example simulates the high Mach number operating state of a high-enthalpy pulsed wind tunnel, with a Mach number of 12, an air flow medium, and a total temperature ≥ 8000K; the length of the nozzle body 5 is 2.2m, and the material is 35CrNi3MoVR.

[0027] Length of the electromagnetic deceleration channel 1 l = 1m, there are 25 groups of electrode pairs I 8L, the electrode spacing of the electrode pair I 8 is 30mm, and the electrode width is 10mm; each group of electrode pairs I 8 forms a closed-loop circuit; the rectangular electromagnet I 2 is symmetrically arranged on both sides, and the rectangular electromagnet I 2 uses an iron-core coil, and the magnetic field intensity is controlled by the magnitude of the coil current, and the intensity range is 0 - 3T.

[0028] Length of the electromagnetic acceleration channel 3 n = 1m, there are also 25 groups of electrode pairs II 12M. Similarly, the electrode spacing of the electrode pair II 12 is 30mm, and the electrode width is 10mm; each group of electrode pairs II 12 forms a closed-loop circuit, and the rectangular electromagnet II 4 is symmetrically arranged on both sides. The rectangular electromagnet II 4 uses an iron-core coil, and the magnetic field intensity is controlled by the magnitude of the coil current, and the intensity range is 0 - 3T; The resistance value of each loop non-inductive resistor 10 is 2 Ω; the pulse power supply system 6 is powered by grouped capacitors 11, and the charging voltage of each group of capacitors 11 is 0 - 400 V.

[0029] Under the action of the load voltage, an electric field vector is generated E and a current vector J , the current vector J interacts with the magnetic field vector B to induce a Lorentz volume force J × B .

[0030] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. For those skilled in the art, without departing from the principle of the present invention, all the features disclosed in the present invention, or all the steps in the disclosed methods or processes, except for the mutually exclusive features and / or steps, can be combined in any way. The present invention is not limited to the specific details and the illustrated examples here.

Claims

1. An experimental device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel, characterized in that, The test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel is provided with an electromagnetic deceleration channel (1) in the contraction section of the nozzle body (5), and 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 a pulsed power supply system (6), and the pulsed power supply system (6) is connected to a 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 on the upper and lower sides of the contraction section. The electrode spacing of the electrode pairs I (8) is x 1, and the electrode width is y 1. The upper side is the anode of the electrode, and the lower side is the cathode of the electrode. Each group of electrode pairs I (8) forms a closed-loop circuit, and a non-inductive resistor (10) is arranged on the closed-loop circuit; rectangular electromagnets I (2) are symmetrically arranged on the left and right sides of the electromagnetic deceleration channel (1). The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field intensity is controlled in real time according to the magnitude of 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 on the upper and lower sides of the expansion section. The electrode spacing of the electrode pairs II (12) is x 2, and 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 (12) forms a closed-loop circuit, and a non-inductive resistor (10) is also arranged on the closed-loop circuit. The electric field strength is controlled in real time according to the current magnitude; rectangular electromagnets II (4) are symmetrically arranged on the left and right sides of the electromagnetic acceleration channel (3). The left side is the N pole of the electromagnet, and the right side is the S pole of the electromagnet. The magnetic field strength is controlled in real time according to the coil current magnitude.

2. The test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to claim 1, characterized in that, The described electromagnetic deceleration channel (1) and electromagnetic acceleration channel (3) are both segmented Faraday-type channels.

3. The test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to claim 1, characterized in that, The material of the nozzle body (5) is 35CrNi3MoVR.

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

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

6. The test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to claim 1, wherein Insulating layers (9) are arranged 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 alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel 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 the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel, which is used for the test device for alleviating the ablation of the nozzle throat of a high-enthalpy pulsed wind tunnel according to any one of claims 1 to 7, characterized in that, It includes the following steps: S10. Set test parameters; Before the test, according to different test conditions, calculate the current magnitudes required for the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3); according to the current magnitudes, the control system (7) sets the test parameters, and the test parameters include the trigger signals, current magnitudes, and energization times corresponding to the rectangular electromagnet I (2), the electrode pair II (12), and the rectangular electromagnet II (4); S20. Turn on the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3); During the test, at time t1, the diaphragm of the pulse wind tunnel shock tube bursts, and the test device for alleviating the ablation of the nozzle throat of the high-enthalpy pulse wind tunnel is started with the burst signal as the trigger signal, and a constant current is supplied to the rectangular electromagnet I (2) to turn on the electromagnetic deceleration channel (1); at time t2, the shock wave runs to the downstream end of the low-pressure section to generate a high-temperature and high-pressure conductive gas flow, which enters the nozzle throat, and the high-enthalpy gas flow energy is extracted by the electromagnetic deceleration channel (1) and converted into electrical energy and output to the capacitor (11) of the pulse power supply system (6) for storage; At the same time as t1, the electrode pair II (12) is supplied with grouped power, and a constant current is supplied to the rectangular electromagnet II (4) to turn on the electromagnetic acceleration channel (3); at time t3, the gas flow is accelerated through the electromagnetic acceleration channel (3), and then continues to be accelerated and homogenized by the nozzle and reaches the nozzle outlet to form a test flow field; S30. Turn off the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3); After the test, turn off the electromagnetic deceleration channel (1) and the electromagnetic acceleration channel (3), and the test ends.

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