Coupled Heating Model of High-Speed Wind Tunnel Forebody and Inlet and Its Simulation Verification Method

Abstract

The present invention belongs to the technical field of hypersonic vehicle design, and discloses a coupled heating model of a high-speed wind tunnel forebody and an inlet, and a simulation verification method therefor. A heating structure is provided on the coupled heating model of the high-speed wind tunnel forebody and the inlet. Heating rods that are symmetric about the left and right are arranged on the sharp leading edge, heating plates are arranged on the first-stage compression surface, the second-stage compression surface and the shoulder, heat insulation grooves are arranged between the heating plates. At the same time, pressure sensors are arranged on the symmetry center line, and a plurality of temperature measurement points are arranged in the wall surface below the heating plates to perform full-area and full-depth temperature measurement. The simulation verification method of the coupled heating model of the high-speed wind tunnel forebody and the inlet uses three-dimensional transient heat transfer simulation to verify the effectiveness of the thermal protection design, and k-ω the numerical simulation of the SST turbulence model reveals the significant regulation effect of the wall temperature change on the shock wave structure, pressure distribution and turbulence characteristics, and has engineering practical value.

Description

Technical Field

[0001] The present invention belongs to the technical field of hypersonic vehicle design, and particularly relates to a coupled heating model of a high-speed wind tunnel forebody and an inlet and a simulation verification method thereof. Background Art

[0002] When a hypersonic vehicle changes from a cruise state to a return state, its speed will decrease from hypersonic (Ma>5) to supersonic (1.2<Ma<5). In the supersonic stage, the flight speed of the hypersonic vehicle is lower than the cruise speed, and no obvious aerodynamic heating phenomenon will occur. However, in the cruise stage, the heat accumulated on the wall of the hypersonic vehicle has not been radiated out in time. The wall heat still has a significant impact on key flow phenomena such as aerodynamic heat transfer, flow separation, and shock wave / boundary layer interference. Therefore, studying the wall heat in the supersonic stage is crucial for the aerodynamic performance optimization and load reduction design of the vehicle.

[0003] In 2011, Hirschel E H et al. published "Design of hypersonic flight vehicles: some lessons from the past and future challenges", which proposed a thermal experimental technique (Hot Experimental Technique, HET). The thermal experimental technique is a method of heating the model to a high temperature (about 1000K) similar to hypersonic conditions before the wind tunnel starts to operate. The thermal experimental technique can reproduce the model temperature representing hypersonic flight conditions, so as to achieve the wall-total temperature ratio of the real vehicle wall in a high-speed wind tunnel; it can also conduct experimental research on the influence of the wall heat environment generated in the hypersonic stage on the flow phenomena in the supersonic stage.

[0004] Common heating methods in thermal experimental techniques include external radiation heating, embedded resistance element heating, and variable cross-section carbon-carbon (C / C) heating element heating, etc. In 2013, "Hot-wall reentry testing in hypersonic impulse facilities" published by Zander et al. used a carbon-carbon (C / C) element sandwiched between two copper electrodes to generate a surface temperature of approximately 2000K. The heat conduction loss at the electrodes in this heating method cannot be ignored, which will lead to uneven temperature distribution. Resistance Joule heating is a representative method for simulating the temperature of the aircraft wall during high-speed flight. In 2004, "Investigation of an intake injected hot wall scramje" published by Kovachevich et al. heated the intake wall to 500K by means of an internal resistance wire to explore the influence of the intake wall temperature on ignition, and proved that heating the wall will significantly increase the temperature of the boundary layer within 1.4mm near the wall. In 2014, "A new method for prescribing non-uniform wall temperatures on wind tunnel models" published by Neely et al. formed a controllable temperature distribution on the surface of the element by changing the thickness of the reinforced carbon-carbon (RCC) material, and no significant deformation or stress occurred in the element. In 2021, "Hypersonic transition over a heated wall" published by Zhu et al. heated a cone model with a heating rod, and the highest surface temperature of the model was heated to 800K, with a surface temperature difference of 5K, and studied the transition process of the boundary layer on the heated wall; in the experiment, the wall temperature of the model was higher than T w / T 0 (where T w and T 0(the wall temperature and the total temperature respectively) can be controlled to vary between 0.66 and 1.77. In 2020, "Hopkins K J, etal. Electrically-heated flat plate testing in a free-piston driven shock tunnel" published by Chang et al. heated a rectangular graphite plate to a temperature above 800K and observed that the heating wall conditions had a significant impact on the growth of the boundary layer. In 2017, "Reproducing non-uniform surface temperature profiles on hypersonic cruise vehicles in impulsive wind tunnels" published by Vennik et al. conducted heated flat plate experiments in a wind tunnel and compared the boundary layer thicknesses under different temperature conditions of the unheated surface (290K), the uniformly heated surface (1025K), and the non-uniformly heated surface (675K to 1130K); the results showed that there were significant differences in the boundary layer thickness between the unheated and heated models. However, the differences between the uniformly and non-uniformly heated cases were difficult to distinguish and further exploration was needed; the research on the flat plate / compression ramp model showed that as the wall temperature decreased, the size of the separated bubble decreased significantly. In 2024, "Development of force measurement technique for preheated model in hypersonic combined test facility" published by Yang et al. heated a cone model to 435K in a hypersonic combined test facility integrating an arc jet and a shock tunnel and analyzed the different effects of ablation-induced shape changes and surface temperature on the drag coefficient.

[0005] It can be clearly seen from the above literature that the joule heating model provides an effective means for simulating hypersonic wall temperature conditions in ground wind tunnel experiments. The joule heating model has three characteristics: ① heating elements with high resistivity, such as ceramics, such as C / C, graphite, or C / SiC; ② flat plate model or flat plate / compression ramp model; ③ achieving uniform surface temperature or gradient temperature changes while maintaining a reasonable structure. However, in the current literature on the joule heating model, there is a lack of detailed descriptions of the structural state of the joule heating model under thermal loads (whether transient or steady-state conditions). Since it is necessary to ensure the reliability of the model, improve the fluid-thermal-structure interaction, and understand more details about the thermal stress generated by heating the model, the structural state is crucial for the design of the joule heating model.

[0006] At present, there is an urgent need to develop a coupled heating model of the forebody and inlet of a high-speed wind tunnel and its simulation verification method. Summary of the Invention

[0007] One technical problem to be solved by the present invention is to provide a coupled heating model of the forebody and inlet of a high-speed wind tunnel, and another technical problem to be solved by the present invention is to provide a simulation verification method for the coupled heating model of the forebody and inlet of a high-speed wind tunnel.

[0008] The coupled heating model of the forebody and inlet of a high-speed wind tunnel of the present invention realizes a uniform or gradient temperature distribution on the surface through an internal array of far-infrared heating units and a gradient temperature control system, combined with an air heat insulation groove and a zirconia ceramic sensor protection technology. The simulation verification method for the coupled heating model of the forebody and inlet of a high-speed wind tunnel of the present invention uses three-dimensional transient heat transfer simulation to verify the effectiveness of the thermal protection design, and through k-ω The numerical simulation of the SST turbulence model reveals the significant regulation effect of wall temperature changes on the shock wave structure, pressure distribution, and turbulence characteristics.

[0009] The coupled heating model of the forebody and inlet of a high-speed wind tunnel of the present invention is based on a coupled model of the forebody and inlet. An internal flow channel is provided inside the forebody of the coupled model of the forebody and inlet, and the lip is the inlet of the internal flow channel; heating structures are arranged on the wall surfaces of the sharp leading edge, compression surface, and shoulder position of the forebody to form a coupled heating model of the forebody and inlet of a high-speed wind tunnel;

[0010] The heating structure divides the wall surfaces of the compression surface and shoulder position along the oncoming flow direction into a primary compression surface, a secondary compression surface, and a shoulder from front to back; there are 2 heating rods perpendicular to the oncoming flow direction and symmetric about the left and right inside the sharp leading edge, and a temperature measurement point is set at the midpoint of the 2 heating rods; a number of sequentially arranged heating plates are covered along the oncoming flow direction on the inner wall surface of the primary compression surface, and heat insulation grooves are provided between the heating plates; a number of groups of heating plates symmetric about the left and right are covered along the oncoming flow direction on the inner wall surfaces of the secondary compression surface and shoulder, and heat insulation grooves are provided between the groups of heating plates; a number of pressure sensors along the oncoming flow direction are arranged on the center line of the secondary compression surface and shoulder, and heat insulation ceramic tubes are sleeved outside the pressure sensors; a number of temperature measurement points are arranged inside the wall surfaces of the compression surface and shoulder corresponding to each heating plate;

[0011] A set of thermocouples are respectively installed on each temperature measurement point, and the thermocouple wires of each thermocouple are arranged on the inner wall surface of the forebody; the embedding depths of the thermocouple probes of each group of thermocouples are different, realizing temperature measurement over the entire area and entire depth of the wall surfaces of the compression surface and shoulder position.

[0012] Furthermore, independent heating plate temperature adjustment devices are respectively provided on the sharp leading edge and each heating plate; the heating plate temperature adjustment device includes a thermocouple, a data acquisition system, a computer, and a temperature controller;

[0013] The data acquisition system and the temperature controller are respectively connected to the computer; the temperature controller is connected to the heating plate; each group of thermocouples includes 4 thermocouples, among which, 3 thermocouples are measurement thermocouples, which are respectively connected to the data acquisition system and respectively obtain the measurement signals at 3 different depths of the wall surface at the compression surface and the shoulder position; 1 thermocouple is a feedback thermocouple, and the feedback thermocouple is close to the heating plate and is connected to the temperature controller;

[0014] The measurement thermocouples transmit the measurement signals to the data acquisition system to convert them into measured point temperature values. The computer displays the measured point temperature values. The staff sets the target temperature value on the computer and sends the target temperature value to the temperature controller. The temperature controller performs PID control through the feedback thermocouple until the feedback thermocouple heats up to the target temperature value.

[0015] Furthermore, heat-conducting silicone grease is coated on the contact surfaces of the heating rods and each heating plate with the precursor to reduce the contact thermal resistance; the heating plates are far-infrared heating plates.

[0016] The simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention includes the following contents:

[0017] The simulation verification method adopts the k-ω SST turbulence model for supersonic wind tunnel simulation. At the same time, a two-temperature model is adopted within the k-ω SST turbulence model to simulate the transient heat transfer under the supersonic flow state; a two-dimensional computational domain grid is constructed to characterize the flow field characteristics of the central symmetry plane of the inlet duct; the compressible Navier-Stokes equations are solved by the finite volume method; second-order upwind scheme is adopted for spatial discretization; air is based on the perfect gas assumption, and the molecular viscosity coefficient is calculated by the Sutherland formula;

[0018] During the numerical calculation process, the residuals of each equation and the incoming flow mass flow rate of the internal flow path are monitored, and the convergence criterion is that the residuals no longer decrease and the incoming flow mass flow rate is within the preset change range.

[0019] The high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention realizes the precise control of the uniform or gradient temperature distribution on the model surface in the range of 350K to 1000K by embedding multiple groups of heating units in the wall surfaces at the sharp leading edge, compression surface and shoulder position, so as to simulate the wall heat environment of hypersonic aircraft. The simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention proves that the high-speed wind tunnel forebody and inlet duct coupled heating model has precise temperature control and heat insulation protection capabilities, verifies the significant influence of wall temperature change on the flow field structure, and at the same time proves that the high-speed wind tunnel forebody and inlet duct coupled heating model can effectively reproduce the aerodynamic heat coupling effect, establishes a hypersonic inlet duct heat-flow coupling test platform, and has engineering practical value. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the forebody and inlet duct coupling model;

[0021] Figure 2 is a schematic structural diagram of the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0022] Figure 3 is a schematic cross-sectional view of the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0023] Figure 4 is the pressure sensor distribution in the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0024] Figure 5 is the layout diagram of the temperature measurement points in the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0025] Figure 6a is the schematic installation diagram of the thermocouple in the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention (front view);

[0026] Figure 6b is the schematic installation diagram of the thermocouple in the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention (top view);

[0027] Figure 7 is the schematic diagram of the heating plate temperature adjustment device in the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0028] Figure 8a is the experimental schlieren image given by the reference;

[0029] Figure 8b is the Mach cloud diagram of the flow field obtained by the simulation verification method of the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0030] Figure 9a is the comparison diagram of the static pressure distribution on the compression surface of the internal flow path obtained in the embodiment;

[0031] Figure 9b is the comparison diagram of the static pressure distribution on the inner wall surface of the lip obtained in the embodiment;

[0032] Figure 10a is the curve of the wall pressure changing with temperature obtained by the simulation verification method of the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0033] Figure 10b is the curve of the wall shear stress changing with temperature obtained by the simulation verification method of the coupled heating model of the forebody and inlet duct of the high-speed wind tunnel of the present invention;

[0034] Figure 10cThe curve of the change of turbulent viscosity with temperature obtained by the simulation verification method of the coupled heating model of the high-speed wind tunnel forebody and inlet duct of the present invention.

[0035] In the figure, 1. Forebody; 2. Inner flow path; 3. Lip; 4. Sharp leading edge; 5. Compression surface and shoulder position wall surface; 6. Heating rod; 7. Heat insulation groove; 8. Heating plate; 9. Heat insulation ceramic tube; 10. Pressure sensor; 11. Temperature measurement point; 12. Thermocouple; 13. Thermocouple probe; 14. Thermocouple wire; 15. Data acquisition system; 16. Computer; 17. Temperature controller; 18. Feedback thermocouple;

[0036] 501. Shoulder; 502. Secondary compression surface; 503. Primary compression surface. Detailed implementation mode

[0037] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0038] The coupled heating model of the high-speed wind tunnel forebody and inlet duct of the present invention is based on the coupled model of the forebody and inlet duct as shown in Figure 1 . An inner flow path 2 is arranged in the forebody 1 of the coupled model of the forebody and inlet duct, and the lip 3 is the inlet of the inner flow path 2; a heating structure is arranged on the sharp leading edge 4 and the compression surface and shoulder position wall surface 5 of the forebody 1 to form the coupled heating model of the high-speed wind tunnel forebody and inlet duct as shown in Figure 2 、 Figure 3 ;

[0039] The heating structure divides the compression surface and shoulder position wall surface 5 along the oncoming flow direction into a primary compression surface 503, a secondary compression surface 502 and a shoulder 501 in sequence from front to back; two heating rods 6 perpendicular to the oncoming flow direction and symmetric about the left and right are arranged in the sharp leading edge 4, and a temperature measurement point 11 is arranged at the midpoint of the two heating rods 6; a number of heating plates 8 arranged in sequence are covered on the inner wall surface of the primary compression surface 503 along the oncoming flow direction, and heat insulation grooves 7 are arranged between the heating plates 8; a number of groups of heating plates 8 symmetric about the left and right are covered on the inner wall surfaces of the secondary compression surface 502 and the shoulder 501 along the oncoming flow direction, and heat insulation grooves 7 are arranged between the groups of heating plates 8; a number of pressure sensors 10 along the oncoming flow direction as shown in Figure 4 are arranged on the center line of the secondary compression surface 502 and the shoulder 501, and the pressure sensors 10 are sleeved with heat insulation ceramic tubes 9; a number of temperature measurement points 11 are arranged in the compression surface and shoulder position wall surface 5 corresponding to each heating plate 8;

[0040] The distribution of each temperature measurement point 11 is shown in Figure 5 ; A set of thermocouples 12 are respectively installed on each temperature measurement point 11, and the thermocouple wires 14 of each thermocouple 12 are arranged on the inner wall surface of the forebody 1; as shown in Figure 6a 、 Figure 6bAs shown, the embedding depths of the thermocouple probes 13 of each group of thermocouples 12 are different, realizing the temperature measurement of the entire area and the entire depth of the wall surface 5 along the compression surface and the shoulder position.

[0041] Furthermore, as Figure 7 shown, independent heating plate temperature adjustment devices are respectively arranged on the sharp leading edge 4 and each heating plate 8; the heating plate temperature adjustment device includes a thermocouple 12, a data acquisition system 15, a computer 16 and a temperature controller 17;

[0042] The data acquisition system 15 and the temperature controller 17 are respectively connected to the computer 16; the temperature controller 17 is connected to the heating plate 8; each group of thermocouples 12 includes 4 thermocouples 12, wherein, 3 thermocouples 12 are measurement thermocouples, which are respectively connected to the data acquisition system 15 to respectively obtain the measurement signals of the wall surface 5 at 3 different depths at the compression surface and the shoulder position; 1 thermocouple 12 is a feedback thermocouple 18, and the feedback thermocouple 18 is close to the heating plate 8 and is connected to the temperature controller 17;

[0043] The measurement thermocouple transmits the measurement signal to the data acquisition system 15 to convert it into the measured point temperature value, the computer 16 displays the measured point temperature value, the staff sets the target temperature value on the computer 16 and sends the target temperature value to the temperature controller 17, and the temperature controller 17 performs PID control through the feedback thermocouple 18 until the feedback thermocouple 18 rises to the target temperature value.

[0044] Furthermore, heat-conducting silicone grease is coated on the contact surfaces of the heating rods 6 and each heating plate 8 with the forebody 1 to reduce the contact thermal resistance; the heating plate 8 is a far-infrared heating plate.

[0045] The simulation verification method of the high-speed wind tunnel forebody and intake duct coupled heating model of the present invention includes the following contents:

[0046] The simulation verification method uses the k-ω SST turbulence model for supersonic wind tunnel simulation. At the same time, a two-temperature model is adopted in the k-ω SST turbulence model to simulate the transient heat transfer under the supersonic flow state; a two-dimensional computational domain grid is constructed to characterize the flow field characteristics of the intake duct central symmetry plane; the compressible Navier-Stokes equations are solved by the finite volume method; the second-order upwind scheme is used for spatial discretization; the air is based on the perfect gas assumption, and the molecular viscosity coefficient is calculated by the Sutherland formula;

[0047] During the numerical calculation process, the residuals of each equation and the incoming flow mass flow rate of the internal flow path 2 are monitored, and the convergence criterion is that the residuals no longer decrease and the incoming flow mass flow rate is within the preset change range.

[0048] Example: This example refers to the "Experimental investigation of the internal compression inside a hypersonic intake" published by Herrmann et al. in 2002. The internal shock wave system model in the inlet model of the High-Speed Aerodynamics Special Collaborative Research Center of RWTH Aachen University disclosed in the article is adopted, and the simulation verification method of the coupled heating model of the high-speed wind tunnel forebody and inlet in the present invention is verified through the experimental data disclosed in the article. The number of computational grids in this example is 2.83 million.

[0049] In this example, the material of the forebody 1 is FS-136 stainless steel, and the wall thickness is 10 mm; each heating rod 6 has a diameter of 8 mm and a length of 70 mm. There are 7 heating plates 8, which are fixed by cover plates and bolts. The sizes of the 3 heating plates 8 on the primary compression surface 503 are 26 * 130 * 4 mm, and the sizes of the 4 heating plates 8 on the secondary compression surface 502 and the shoulder 501 are 38 * 60 * 4 mm; the base material of the heating plate 8 is glass-ceramics, which can withstand a maximum temperature of 800 °C, and the heating power is 0.134 kW / m 2 . The temperature controller 17 can provide high-precision temperature measurement and control for the heating plate 8, effectively reducing temperature fluctuations and enabling the model wall surface to reach and stabilize at the set temperature faster. The data acquisition system 15 has an acquisition accuracy of ±0.2 °C and a scanning interval of 100 ms, and calculates the model surface temperature and the heat flux density in the wall thickness direction according to Fourier's law of heat conduction.

[0050] There are 29 temperature measurement points 11. One, 20, 4, and 4 temperature measurement points are arranged on the sharp leading edge 4, the primary compression surface 503, the secondary compression surface 502, and the shoulder 501 respectively. Each temperature measurement point 11 consists of three thermocouples 12, with a temperature range of -73 °C to 482 °C and a temperature measurement accuracy of ±1.1 °C. The three thermocouples 12 measure the temperatures at depths of 1 mm, 5.5 mm, and 9 mm respectively.

[0051] The given oncoming flow conditions for the experiment are: Mach number 2.5, total pressure 5600 kPa, static pressure 327.75 kPa, total temperature 295 K, static temperature 131 K, the length of the isolation section behind the inlet throat is 79.3 mm, and the outlet is in a non-backpressure through-flow state. Figure 8a is the experimental schlieren image published in the technical literature, Figure 8b is the flow field Mach number cloud image obtained by performing simulation calculations on Figure 8a using the simulation verification method of the coupled heating model of the high-speed wind tunnel forebody and inlet in the present invention. It can be seen that the positions and shapes of various oblique shock waves and reflected shock waves in the internal flow channel 2 obtained by the two are basically in agreement. Figure 9a 、 Figure 9bThe static pressure distribution comparison diagrams of the internal flow path compression surface and the inner wall surface of the lip are respectively shown. It can be seen that the pressure along the path of the two is basically consistent. The comparison results show that the simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention can achieve high simulation accuracy. It is feasible to use the simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention to study the influence of wall temperature on the flow field. The simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention has effectiveness.

[0052] Continue to use the simulation verification method of the high-speed wind tunnel forebody and inlet duct coupled heating model of the present invention to study the influence of different wall temperatures on the flow field structure. The set incoming flow conditions are: Mach number 3.0, total pressure 360 kPa, static pressure 9.6 kPa, total temperature 288 K, static temperature 102.86 K, the length of the isolation section behind the inlet duct throat is 79.3 mm, and the outlet is in a non-backpressure through-flow state. Constant wall temperatures are set at the leading edge, compression surface, and shoulder positions of the inlet duct. The obtained Figure 10a shows that as the wall temperature increases, the pressure rising point near the wall moves to the left, indicating that the increase in wall temperature causes the shock wave on the first-stage compression surface 503 to move forward and the peak pressure at the shoulder to decrease; when heating from 400 K to 1000 K, the peak pressure drops by 11.8%, indicating that wall heating can effectively relieve the local high-pressure load; Figure 10b shows that the shear stress of the first-stage compression surface 503 decreases monotonically with the increase in temperature, indicating that the fluid viscous dissipation effect weakens with wall heating and the boundary layer velocity gradient decreases; Figure 10c shows that the turbulent viscosity is highly sensitive to the wall temperature; when rising from 400 K to 1000 K, the viscosity drops suddenly by 98.8%, indicating that wall heating significantly suppresses the turbulent pulsation intensity, resulting in a sharp attenuation of the turbulent transport ability in the near-wall region. It can be proved that the wall temperature has a significant regulatory effect on the aerodynamic characteristics of the hypersonic inlet duct, providing an important reference basis for aerodynamic performance optimization and load reduction design.

[0053] The high-speed wind tunnel forebody and inlet duct coupled heating model and its simulation verification method of this embodiment have the following characteristics:

[0054] a. Establish a multi-physical field coupling model;

[0055] An inlet duct model integrating electric heating, gradient temperature control, and pressure measurement is constructed. Good temperature uniformity is achieved through the layout of heating units and the PID algorithm. The heat insulation groove improves the lateral thermal resistance, and the zirconia ceramic protection reduces the temperature rise rate of the pressure sensor by 67%, thus realizing the synchronous measurement of multiple parameters in a high-temperature environment;

[0056] b. Have thermodynamic response characteristics;

[0057] Simulation verification shows that for the coupled heating model of the forebody and inlet, the surface temperature differences are 8.2K and 26.3K respectively when heated at 550K and 1000K, the maximum thermal deformation is 0.195mm, and the dimensional ratio < 2%, which is lower than the allowable threshold of the high-speed wind tunnel test; at the same time, by establishing the fitting curve of surface temperature - heat flux density and adjusting the working conditions of the heating unit based on this correlation feature, a gradient temperature field can be accurately constructed on the surface of the coupled heating model of the forebody and inlet, so as to realize the physical simulation of the aerodynamic heating effect in the wind tunnel test;

[0058] c. Verify the wall thermal effect;

[0059] When the wall temperature of the coupled heating model of the forebody and inlet rises from 400K to 1000K, the shock wave can move forward by 12% and the peak pressure can be reduced by 11.8%. At the same time, the turbulent viscosity drops suddenly by 98.8%. The simulation verification method of the coupled heating model of the forebody and inlet verifies that the wall temperature has a significant influence on the aerodynamic load distribution and viscous dissipation characteristics of the hypersonic inlet flow field, providing the key parameter correlation law and theoretical support for the subsequent verification of the thermal - flow coupling mechanism, aerodynamic performance optimization and load reduction design research of the wind tunnel.

[0060] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and 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. High-speed wind tunnel forebody and inlet coupled heating model, characterized in that: The high-speed wind tunnel forebody and air inlet coupled heating model is based on the forebody and air inlet coupled model. The forebody (1) of the forebody and air inlet coupled model is provided with an inner flow channel (2), and the lip (3) is the entrance of the inner flow channel (2); a heating structure is provided on the sharp leading edge (4) and the compression surface and the shoulder position wall (5) of the forebody (1), so as to form the high-speed wind tunnel forebody and air inlet coupled heating model; The heating structure divides the compression surface and the shoulder position wall surface (5) into a primary compression surface (503), a secondary compression surface (502) and a shoulder (501) from front to back according to the incoming flow direction; two heating rods (6) perpendicular to the incoming flow direction and symmetrical to the left and right are arranged in the sharp front edge (4), and a temperature measuring point (11) is arranged at the midpoint of the two heating rods (6); the inner wall surface of the primary compression surface (503) is covered with a plurality of sequentially arranged heating plates (8) in the incoming flow direction, and each heating plate (8) is separated by a heat insulation groove. (7); a plurality of groups of bilaterally symmetrical heating plates (8) are sequentially covered on the secondary compression surface (502) and the inner wall surface of the shoulder (501) along the incoming flow direction, and a heat insulation groove (7) is spaced between each group of heating plates (8); a plurality of pressure sensors (10) are arranged along the incoming flow direction on the center line of the secondary compression surface (502) and the shoulder (501), and a heat insulation ceramic tube (9) is sheathed outside the pressure sensor (10); a plurality of temperature measuring points (11) are arranged inside the compression surface and the shoulder position wall surface (5) corresponding to each heating plate (8); A group of thermocouples (12) is installed on each temperature measuring point (11), and the thermocouple wire (14) of each thermocouple (12) is arranged on the inner wall surface of the front body (1); the thermocouple probe (13) of each group of thermocouples (12) is embedded at a different depth, so that the full area and full depth temperature measurement along the compression surface and the shoulder position wall surface (5) is achieved.

2. The high-speed wind tunnel precursor and air inlet coupled heating model according to claim 1, characterized in that: The sharp leading edge (4) and each heating plate (8) are respectively provided with an independently controlled heating plate temperature regulating device; the heating plate temperature regulating device comprises a thermocouple (12), a data acquisition system (15), a computer (16) and a temperature controller (17); The data acquisition system (15) and the temperature controller (17) are respectively connected to the computer (16); the temperature controller (17) is connected to the heating plate (8); each group of thermocouples (12) includes four thermocouples (12), of which three thermocouples (12) are measuring thermocouples, which are respectively connected to the data acquisition system (15) to obtain measurement signals of the compression surface and the shoulder position wall surface (5) at three different depths; one thermocouple (12) is a feedback thermocouple (18), which is close to the heating plate (8) and connected to the temperature controller (17); The measuring thermocouple transmits the measuring signal to the data acquisition system (15) and converts it into the measuring point temperature value. The computer (16) displays the measuring point temperature value. The staff sets the target temperature value on the computer (16) and sends the target temperature value to the temperature controller (17). The temperature controller (17) performs PID control through the feedback thermocouple (18) until the feedback thermocouple (18) is heated to the target temperature value.

3. The high-speed wind tunnel precursor and air inlet coupled heating model according to claim 1, characterized in that: The contact surfaces of the heating rod (6) and each heating plate (8) with the precursor (1) are coated with thermally conductive silicone grease to reduce contact thermal resistance; the heating plate (8) is a far-infrared heating plate.

4. A simulation verification method for a high-speed wind tunnel precursor and an air inlet coupled heating model, which is used for the high-speed wind tunnel precursor and an air inlet coupled heating model as claimed in any one of claims 1 to 3, characterized in that: Includes the following: The simulation verification method adopts the k-ω SST turbulence model for supersonic wind tunnel simulation, and at the same time, a dual-temperature model is used in the k-ω SST turbulence model to simulate transient heat transfer under supersonic flow conditions; a two-dimensional computational domain grid is constructed to characterize the flow field characteristics of the central symmetric surface of the inlet; the compressible Navier-Stokes equations are solved by the finite volume method; a second-order upwind scheme is used for spatial discretization; air is based on the perfect gas assumption, and the molecular viscosity coefficient is calculated using the Sutherland formula; During the numerical calculation process, the residuals of each equation and the incoming mass flow rate of the inner flow channel (2) are monitored, and the convergence criterion is that the residuals no longer decrease and the incoming mass flow rate is within a preset range of variation.

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