CN112067240A - Method for determining surface recovery enthalpy of flat model under arc wind tunnel condition - Google Patents
Method for determining surface recovery enthalpy of flat model under arc wind tunnel condition Download PDFInfo
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Abstract
The invention relates to a method for determining surface airflow recovery enthalpy of a flat model under an electric arc wind tunnel condition. Firstly, the electric arc heats the wind tunnel to generate a high-temperature flow field; measuring the internal temperature response of the thin-wall flat plate model in a high-temperature flow field; obtaining the hot wall heat flux density of the flat plate model at different wall surface temperatures by using the data processing method; and obtaining the recovery enthalpy of the surface air flow of the flat plate model by using the recovery enthalpy calculation method. The method can simply and effectively determine the surface airflow recovery enthalpy of the flat model under the condition of the electric arc wind tunnel, and can provide powerful test technical support for the design and development of a large-area thermal protection system of the hypersonic aircraft.
Description
Technical Field
The invention relates to a method for determining surface recovery enthalpy of a flat plate model under an electric arc wind tunnel condition, and belongs to the field of thermal protection design of aircrafts.
Background
Hypersonic aircraft experience extremely harsh aerodynamic heating environments during entry into the atmosphere, and therefore need to be protected by designing suitable thermal protection systems. The design of the thermal protection system generally selects a few typical states of the flight orbit of the aircraft to carry out a steady-state ground thermal protection assessment test, and then thermal protection data of the whole flight orbit are obtained by extrapolation according to data obtained by the test and serve as a design basis. The electric arc heating test equipment provides unique capability of high enthalpy, long time and convective flow, and is indispensable ground heat-proof test equipment for performing aerodynamic heat ground examination test research on materials and heat-proof structures of hypersonic aircrafts.
In the process of developing the hypersonic aerocraft, a large number of pneumatic thermal simulation tests need to be carried out on the ground to check the performance of the heat-proof material and the thermal structure performance of the hypersonic aerocraft. From the examination of ground simulation tests, after the electric arc heating wind tunnel and the spray pipe are selected, the total enthalpy, the pressure and the heat flux density of airflow become the most main flow field characterization parameters. The recovery enthalpy of the airflow surface determines the highest temperature which can be reached by the surface of the material model, and the accurate simulation of the recovery enthalpy is very important for the low-redundancy heat-proof design of the high-supersonic speed flight chess in the adjacent space. Particularly, when the performance of the micro-ablation heat-proof material is in the maximum bearing temperature boundary, a ground heat-proof test is needed to simulate the exact air flow recovery enthalpy of the surface of the model.
In a heat-proof assessment test of a ground electric arc ground flat plate model, the total enthalpy of airflow is firstly measured and determined, and then the recovery enthalpy is determined according to an empirical formula and the total enthalpy of the airflow. Due to the fact that in the high-temperature airflow flowing under the actual test condition, partial energy of a boundary layer can be taken away under the water cooling effect of the wall surface of the spray pipe, and the enthalpy of the recovered wall surface airflow is gradually reduced along the flowing direction. In addition, due to the unbalanced characteristic of high-temperature flow, the parameters of the gas flow at the outlet of the spray pipe are greatly influenced, so that the recovery enthalpy obtained by the engineering method has larger deviation from the actual enthalpy, and a more refined recovery enthalpy determination method is urgently needed.
In general, accurate determination of the surface recovery enthalpy of a flat plate model under the condition of an electric arc wind tunnel is a technical problem to be solved in the field.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a method for determining the surface recovery enthalpy of a flat plate model under the condition of an electric arc wind tunnel, determines the accurate recovery enthalpy of the surface airflow of the flat plate model under the condition of the electric arc wind tunnel, and provides powerful test technical support for the design and development of a thermal protection system of a hypersonic aircraft.
The purpose of the invention is realized by the following technical scheme: a method for determining surface recovery enthalpy of a flat model under an electric arc wind tunnel condition comprises the following steps:
(1) arranging N thermocouples on the back surface of the thin-wall flat plate test model (4), and placing the thin-wall flat plate test model (4) in an electric arc wind tunnel test section; (the arc wind tunnel test section requires a closed vacuum space)
(2) Heating the thin-wall flat plate test model (4) by using high-temperature (the temperature is 500K-10000K) airflow generated by the arc wind tunnel system, and measuring the total pressure P0, the flow G and the thermocouple temperature Te (i) (i is 1, 2, 3, … N) (namely representing the internal temperature of the thin-wall flat plate test model (4)) of the high-temperature airflow in the test process (the test process means that the arc heater 1 works within 10 s); the test model (4) is preferably 5-10 mm, and the material is high-temperature alloy or a silicon carbide plate;
(3) according to the total pressure P0 of the high-temperature airflow and the flow G of the high-temperature airflow measured in the test process, the total enthalpy H of the high-temperature airflow is calculated0；
(4) And calculating the hot wall heat flow density qw-t1 and the hot wall heat flow density qw-t2 of the flat plate test model at the set temperature t1 and t2 respectively by using the measured internal temperature Te (i) of the thin-wall flat plate test model (4). (the temperature difference between t1 and t2 is preferably greater than 200K, t1< t2, t1 is 300K or greater)
(5) By using the set temperatures t1 and-t 2 and the hot wall heat flow densities qw-t1 and qw-t2 and the total enthalpy H of the high-temperature gas flow of the flat plate test model at the temperatures t1 and-t 20And calculating and determining the surface air flow recovery enthalpy Hr of the flat plate model.
Preferably, the total enthalpy H of the high temperature gas stream is calculated in step (3)0The formula of (1) is:
in the formula: the lance is preferably a Laval lance H0The total enthalpy of the high-temperature gas after the jet pipe is accelerated is kJ/kg; p0The total pressure of the high-temperature air flow is expressed in MPa; a. the*Is the throat area of the Laval nozzle in mm2(ii) a G is the mass flow of the high-temperature airflow, and the unit is kg/s; cdIs the flow coefficient.
Preferably, the formulas for calculating the hot wall heat flow density qw-t1 and qw-t2 of the flat plate test model in the step (4) are respectively as follows:
wherein qw-t1 is the surface heat flux density of thin-wall flat plate model with inner wall temperature at t1, and the unit is kW/m2Rho is the density of thin-wall flat model material and the unit is kg/m3Cp is the specific heat of the slab model material, expressed in kJ/(kg · K), h is the thin-walled slab model thickness, expressed in m, t1 is the temperature of the slab model back at time dt1, expressed in ° c, dt1 is the time for the slab model back temperature to rise to t1, expressed in s, t0 is the slab model back initial temperature, t2 is the slab model back temperature at time dt2, dt2 is the time for the slab model back temperature to rise to t 2.
Preferably, the electric arc wind tunnel comprises an electric arc heater (1), a mixing and pressure stabilizing chamber (2), a spray pipe (3), a test section and a vacuum system; the flat plate test model (4) is placed in the test section, the electric arc heater (1) generates high-temperature airflow, the high-temperature airflow is mixed with normal-temperature gas introduced into the mixing pressure stabilizing chamber (2), the mixed high-temperature airflow is accelerated through the spray pipe (3), the accelerated high-temperature airflow heats the flat plate test model (4), and the heated gas is finally discharged through the vacuum system.
Preferably, the arc heater (1) is a tubular arc heater, a segmented arc heater or a laminated arc heater.
Preferably, the flat plate test model (4) is of a hollow metal structure, and the thickness dimension h of the thin-wall flat plate is less than 2 mm.
Preferably, the thermocouple temperature te (i), i ═ 1, 2, 3, … N, indicates the internal temperature of the thin-walled flat plate test model (4).
Further preferably, the specific formula of the enthalpy of recovery of the surface gas flow Hr of the flat plate model calculated and determined by using the hot wall heat flow density qw-t1 and qw-t2 of the flat plate test model in the step (5) is as follows:
(1) when the total enthalpy of the gas flow is within the range of 600kJ/kg < H0 ≤ 5000 kJ/kg:
(2) when the total enthalpy of the gas flow is within the range of 5000kJ/kg < H0 ≤ 20000 kJ/kg:
in the formula, k is a recovery enthalpy calculation coefficient; hw-t1 is the wall gas enthalpy value when the wall temperature of the flat model is t1, and the unit is kJ/kg; hw-t2 is the wall gas enthalpy value when the wall temperature of the flat plate model is t2, and the unit is kJ/kg.
Compared with the prior art, the invention has the following advantages:
(1) the method utilizes the back temperature response of the thin-wall flat model under the condition of measuring the electric arc wind tunnel in the test process to calculate the hot wall heat flux density of the flat model under different temperature conditions, and the surface air flow recovery enthalpy of the flat model is obtained through the formula calculation provided by the invention. Powerful test technical support and data support are provided for the design and development of the thermal protection system of the hypersonic aircraft.
(2) The invention provides an effective measurement and calculation method for the surface gas flow recovery enthalpy of a flat plate model, which can obtain the real and effective surface recovery enthalpy of the flat plate model under the condition of the wall surface of a water-cooling spray pipe.
(3) According to the invention, the back surface temperature of the thin-wall flat model is measured, the flat hot wall heat flow and the flat surface air flow recovery enthalpy are calculated, and the method has the advantages of good robustness and high efficiency.
Drawings
FIG. 1 is a schematic view of a system of the test apparatus of the present invention.
FIG. 2 is a schematic view of a thin-wall flat test model according to the present invention.
FIG. 3 is a graph of the internal temperature response test of the model of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
The invention relates to a method for determining surface airflow recovery enthalpy of a flat model under an electric arc wind tunnel condition. Firstly, the electric arc heats the wind tunnel to generate a high-temperature flow field; measuring the internal temperature response of the thin-wall flat plate model in a high-temperature flow field; obtaining the hot wall heat flux density of the flat plate model at different wall surface temperatures by using the data processing method; and obtaining the recovery enthalpy of the surface air flow of the flat plate model by using the recovery enthalpy calculation method. The method can simply and effectively determine the surface airflow recovery enthalpy of the flat model under the condition of the electric arc wind tunnel, and can provide powerful test technical support for the design and development of a large-area thermal protection system of the hypersonic aircraft.
In the invention, the surface airflow recovery enthalpy of the heat-proof model determines the highest temperature which can be reached by the surface of the material model, and the accurate simulation of the recovery enthalpy is very important for the low-redundancy heat-proof design of the hypersonic flight chess in the adjacent space. In a heat-proof assessment test of a ground electric arc ground flat plate model, the total enthalpy of airflow is firstly measured and determined, and then the recovery enthalpy is determined according to an empirical formula and the total enthalpy of the airflow. Due to the fact that in the high-temperature airflow flowing under the actual test condition, partial energy of a boundary layer can be taken away under the water cooling effect of the wall surface of the spray pipe, and the enthalpy of the recovered wall surface airflow is gradually reduced along the flowing direction. In addition, due to the unbalanced characteristic of high-temperature flow, the parameters of the gas flow at the outlet of the spray pipe are greatly influenced, so that the recovery enthalpy obtained by the engineering method has larger deviation from the actual enthalpy, and a more refined recovery enthalpy determination method is urgently needed.
The invention aims to overcome the defects of the prior art, provides a method for determining the surface recovery enthalpy of a flat plate model under the condition of an electric arc wind tunnel, quantitatively determines the accurate recovery enthalpy of the surface airflow of the flat plate model under the condition of the electric arc wind tunnel, and provides powerful test technical support for the design and development of a thermal protection system of a hypersonic aircraft.
The invention relates to a method for determining surface recovery enthalpy of a flat model under an electric arc wind tunnel condition, wherein a test system (namely an electric arc wind tunnel) used by the method is shown in figure 1 and comprises the following steps: the device comprises an electric arc heater 1, a mixing and pressure stabilizing chamber 2, a spray pipe 3, a test model 4, a test section, a vacuum system and the like. Wherein 1 and 2 are coaxially fastened and connected, 2 and 3 are also coaxially fastened and connected, 1, 2 and 3 are main equipment for testing hypersonic high-temperature gas, and 4 is placed on a flat model support at the outlet of a spray pipe 3 (the spray pipe 3 is preferably made of fine iron material) and used for measuring the internal temperature response of a thin-wall flat model under the high-temperature gas.
The preferred embodiment of the arc wind tunnel according to the present invention is as follows to further improve the effect of recovery enthalpy determination.
The preferred scheme of the arc heater 1 is as follows: preferably 12MW tubular arc heaters, which are so named because their front and rear electrodes are tubular. The front and rear electrodes are connected by a cyclone chamber in the middle of the heater, a high-speed rotating airflow is introduced from the cyclone chamber, the electric arc is restrained at the center of the tube, and the electric arc is lengthened and stably burnt by the aerodynamic force of the rotating airflow.
The preferred scheme of the mixing pressure stabilizing chamber 2 is as follows: the purpose of the mixing plenum is to reduce the total enthalpy of the gas stream and stabilize the pressure of the gas stream. And (3) introducing a certain amount of cold air into the mixing and pressure stabilizing chamber, and fully mixing the cold air with the high-temperature air flow generated by the electric arc heater to achieve the required total enthalpy and total pressure of the air flow. The total pressure of the airflow in front of the spray pipe and the total temperature of the airflow in a low state can be measured in the mixing pressure stabilizing chamber.
The spray pipe 3 is preferably as follows: in this test, a laval supersonic nozzle with a rectangular cross section is preferably used, the throat size of the nozzle is preferably 20mm x 60mm, the outlet size is preferably 120mm x 60mm, and the nominal mach number of the gas flow is preferably 3.4. The spray pipe adopts an integral punching cooling method, so that the spray pipe is not deformed at high temperature and high pressure, and the stability of a high-temperature flow field in the test process is further ensured.
In the test section, the preferred scheme is specifically as follows: the test section is preferably a rectangular parallelepiped, and the length, width and height of the test section are preferably 2m, 2m and 2m, respectively.
The preferred scheme of the vacuum system is as follows: the vacuum system consists of a vacuum pipeline, a vacuum valve, a vacuum pump set and a vacuum tank.
As shown in fig. 2, the model to be tested is a thin-wall flat model, the preferred thickness h of the model is less than 2mm, a plurality of temperature measuring K-type thermocouples are distributed in the model, and the preferred arrangement requirements are as follows: n thermocouples are uniformly distributed in the center of the model, preferably N is greater than 3, the minimum distance between the two thermocouples is preferably 10mm, and the temperature measurement effect is improved.
The invention relates to a method for determining surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel, which comprises the following implementation steps of:
(1) the tubular electric arc heater is mainly composed of a front electrode, a rear electrode, an arc chamber, a magnetic field coil and the like, and the maximum electric arc power of the tubular electric arc heater can reach 12 MW. Tubular arc heaters are so named because their front and rear electrodes are tubular. The front and rear electrodes are connected by a cyclone chamber in the middle of the heater, a high-speed rotating airflow is introduced from the cyclone chamber, the electric arc is restrained at the center of the tube, and the electric arc is lengthened and stably burnt by the aerodynamic force of the rotating airflow. The arc heater has the characteristics of simple structure, convenient operation and capability of working under high current, thereby obtaining higher arc chamber pressure and arc power.
The purpose of the mixing plenum is to reduce the total enthalpy of the gas stream and stabilize the pressure of the gas stream. And (3) introducing a certain amount of cold air into the mixing and pressure stabilizing chamber, and fully mixing the cold air with the high-temperature air flow generated by the electric arc heater to achieve the required total enthalpy and total pressure of the air flow. The total pressure of the airflow in front of the spray pipe and the total temperature of the airflow in a low state can be measured in the mixing pressure stabilizing chamber.
In the test, a laval supersonic nozzle having a rectangular cross section is used, the throat size (throat rectangular, width by length) of the nozzle is preferably 20mm × 60mm, the outlet size (throat rectangular, length by width) is preferably 120mm × 60mm, and the nominal mach number of the gas flow is preferably 3.4. The spray pipe adopts an integral punching cooling method, so that the spray pipe is not deformed at high temperature and high pressure, and the stability of a high-temperature flow field in the test process is ensured.
And placing the test model 4 with the arranged thermocouples in a test section of the system, wherein the test model 4 is of a hollow structure, and a plurality of thermocouples are arranged on the inner surface. The electric arc heater 1 starts to be ventilated and electrified, high-temperature gas is generated, the high-temperature gas is mixed with normal-temperature gas introduced into the mixing and pressure stabilizing chamber 2, the mixed gas is accelerated through the spray pipe 3, the accelerated high-temperature gas heats the front surface of a model 4 to be tested, and the heated gas is finally discharged through a vacuum system; during the test, the total pressure P0 of the hot gas, the flow rate G of the hot gas and the internal temperature Ti (i ═ 1, 2, …) of the test model were measured, as shown in fig. 3, and a plurality of thermocouples were arranged on the thin-wall flat model to measure the internal temperature response.
(2) Calculating the total enthalpy H of the high-temperature gas after the acceleration of the spray pipe 3 according to the formula (1) by a balanced sound velocity method0。
In the formula:
H0the total enthalpy of the hot gas after acceleration of the lance 3, in units of: kJ/kg;
P0the total pressure of the high-temperature gas stream after acceleration of the lance 3, in units of: MPa;
A*throat area of the nozzle 3, unit: mm is2(ii) a (the nozzle is preferably a Laval supersonic nozzle, throatThe way is located the narrowest department of cross-sectional area in the middle of the spray tube, and the spray tube divide into in proper order: inlet section-convergent section-throat-divergent section-outlet section)
G-gas mass flow in the nozzle 3, unit: kg/s;
Cd-the flow coefficient of the throat of the lance 3.
(3) And calculating hot wall heat flow densities qw-t1 and qw-t2 of the flat plate test model by using the formula (2) according to the measured temperature response of the flat plate model.
Wherein qw-t1 is the surface heat flux density of thin-wall flat plate model with inner wall temperature at t1, and the unit is kW/m2Wherein qw-t2 is the surface heat flux density of thin-wall flat plate model with inner wall temperature at t2, and the unit is kW/m2(preferably, the temperature difference between t1 and t2 is more than 200K, t1<t2, t1 is more than or equal to 300K), rho is the density of the thin-wall flat plate model material, and the unit is kg/m3Cp is the specific heat of the flat model material and is represented by kJ/(kg. K), h is the thickness of the thin-wall flat model and is represented by m, t1 is the temperature of the back surface of the flat model at the time dt1 and is represented by DEG C1 is the time for the back surface of the flat model to rise to t1 and is represented by s, t0 is the initial temperature of the back surface of the flat model (preferably, the surface heated by the high-temperature air flow is the front surface and the other surface is the back surface), t2 is the temperature of the back surface of the flat model at the time dt2, and dt2 is the time for the back surface of the flat model to rise to t 2.
(4) The hot wall heat flow density qw-t1 and qw-t2 of the flat plate test model are used for calculating and determining the surface air flow recovery enthalpy Hr of the flat plate model, and the preferable formula is as follows:
(1) when the total enthalpy of the airflow at the outlet of the spray pipe 3 is within the range of 600kJ/kg < H0 < 5000 kJ/kg:
in the formula, k is a recovery enthalpy calculation coefficient; hw-t1 is the wall gas enthalpy value when the wall temperature of the flat model is t1, and the unit is kJ/kg; hw-t2 is the wall gas enthalpy value when the wall temperature of the flat plate model is t2, and the unit is kJ/kg.
(2) When the total enthalpy of the gas flow at the outlet of the spray pipe 3 is within the interval of 5000kJ/kg < H0 ≤ 20000 kJ/kg:
the preferred thickness h of the thin-walled flat plate model of the invention is 2mm, and the total pressure P0 measured by the test is 0.38MPa, and the flow rate G is 0.12 kg/s. Calculating by using the step (2) to obtain total enthalpy H0 of the gas flow which is 3200 kJ/kg; according to the step (3), calculating to obtain the flat plate hot wall heat flow of
qwt1(t1＝70℃)＝150kW/m2，qwt1(t1＝300℃)＝141kW/m2. According to the step (4), the recovery enthalpy Hr of the flat plate model is calculated to be 1600 kJ/kg. Because the heat flux density of the flat plate model under different wall surface temperature conditions is directly measured, and the influence of factors such as spray pipe water cooling and the like on the loss of the enthalpy value of the air flow is considered, the accuracy of the surface air flow recovery enthalpy of the flat plate model obtained by the method is higher than that of the traditional empirical coefficient method. Compared with theoretical analysis, the deviation of the enthalpy of air flow recovery obtained by the method is within 10%, and the reliability is good.
In order to further improve the accuracy of calculating the recovery enthalpy, the total enthalpy interval of the gas flow is preferably refined [ A kJ/kg, B kJ/kg ], wherein 600< A < B < 20000; and the value of the constant coefficient a/b/c in the enthalpy calculation coefficient is adjusted again according to experience and theoretical analysis.
Calculating and determining the surface air flow recovery enthalpy Hr of the flat plate model, wherein the preferable formula is as follows:
(1) when the total enthalpy of the gas flow is in the interval A kJ/kg < H0 ≤ B kJ/kg:
the method utilizes the back temperature response of the thin-wall flat model under the condition of measuring the electric arc wind tunnel in the test process to calculate the hot wall heat flux density of the flat model under different temperature conditions, and the surface air flow recovery enthalpy of the flat model is obtained through the formula calculation provided by the invention. The method provides powerful test technical support and data support for the design and development of a thermal protection system of the hypersonic aircraft, and the invention provides an effective measurement and calculation method for the surface airflow recovery enthalpy of the flat plate model, so that the real and effective surface recovery enthalpy of the flat plate model under the wall surface condition of the water-cooling spray pipe can be obtained.
According to the invention, the back surface temperature of the thin-wall flat model is measured, the flat hot wall heat flow and the flat surface air flow recovery enthalpy are calculated, and the method has the advantages of good robustness and high efficiency.
The above description is only for the best mode of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Those skilled in the art will appreciate that the invention may be practiced without these specific details.
Claims (10)
1. A method for determining surface recovery enthalpy of a flat model under an electric arc wind tunnel condition is characterized by comprising the following steps:
(1) arranging N thermocouples on the back surface of the thin-wall flat plate test model (4), and placing the thin-wall flat plate test model (4) in an electric arc wind tunnel test section;
(2) the electric arc wind tunnel system generates high-temperature airflow to heat the thin-wall flat plate test model (4), and the total pressure P0, the flow G and the thermocouple temperature Te (i) of the high-temperature airflow are measured in the test process, wherein i is 1, 2, 3 or … N;
(3) according to the total pressure P0 of the high-temperature airflow and the flow G of the high-temperature airflow measured in the test process, the total enthalpy H of the high-temperature airflow is calculated0；
(4) Calculating the hot wall heat flow density qw-t1 and the hot wall heat flow density qw-t2 of the flat plate test model at the set temperature t1 and t2 respectively by using the internal temperature Te (i) of the thin-wall flat plate test model (4) obtained by measurement;
(5) by using the set temperatures t1 and-t 2 and the hot wall heat flow densities qw-t1 and qw-t2 and the total enthalpy H of the high-temperature gas flow of the flat plate test model at the temperatures t1 and-t 20And calculating and determining the surface air flow recovery enthalpy Hr of the thin-wall flat plate test model (4).
2. The method for determining the heat flux density of a sharp leading edge under the condition of an electric arc wind tunnel according to claim 1, wherein: calculating the total enthalpy H of the high-temperature gas flow in the step (3)0The formula of (1) is:
in the formula: h0The total enthalpy of the high-temperature gas after the jet pipe is accelerated is kJ/kg; p0The total pressure of the high-temperature air flow is expressed in MPa; a. the*Is the area of the throat of the nozzle in mm2(ii) a G is the mass flow of the high-temperature airflow, and the unit is kg/s; cdIs the flow coefficient of the nozzle throat.
3. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: in the step (4), the formulas for calculating the hot wall heat flow density qw-t1 and qw-t2 of the flat plate test model are respectively as follows:
wherein qw-t1 is the surface heat flux density of thin-wall flat plate model with inner wall temperature at t1, and the unit is kW/m2Rho is the density of thin-wall flat model material and the unit is kg/m3Cp is the specific heat of the flat model material and is expressed in kJ/(kg. K), h is the thin-wall flat model thickness and is expressed in m, t1 is the temperature of the back surface of the flat model at time dt1 and is expressed in DEG C, dt1 is the time for the back surface temperature of the flat model to rise to t1 and is expressed in s, t0 is the initial temperature of the back surface of the flat model, t2 is the temperature of the back surface of the flat model at time dt2, and dt2 is the time for the back surface temperature of the flat model to rise to t 2.
4. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: the electric arc wind tunnel comprises an electric arc heater (1), a mixing pressure stabilizing chamber (2), a spray pipe (3), an electric arc wind tunnel test section and a vacuum system; the flat plate test model (4) is placed in the test section, the electric arc heater (1) generates high-temperature airflow, the high-temperature airflow is mixed with normal-temperature gas introduced into the mixing pressure stabilizing chamber (2), the mixed high-temperature airflow is accelerated through the spray pipe (3), the accelerated high-temperature airflow heats the flat plate test model (4), and the heated gas is finally discharged through the vacuum system.
5. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: the arc heater (1) is a tubular arc heater, a segmented arc heater or a laminated arc heater.
6. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: the flat plate test model (4) is made of high-temperature-resistant materials, and the thickness h of the thin-wall flat plate is less than 10 mm.
7. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: and generating high-temperature airflow by the electric arc wind tunnel to heat the thin-wall flat plate test model (4), wherein the temperature of the high-temperature airflow is 500K-10000K.
8. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: the thin-wall flat plate test model (4) is 5 mm-10 mm thick and is made of high-temperature alloy or silicon carbide plate.
9. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: the test process means that the arc heater 1 is turned on, and the arc heater 1 continuously works within 10 s.
10. The method for determining the surface recovery enthalpy of a flat model under the condition of an electric arc wind tunnel according to claim 1 or 2, characterized in that: thermocouple temperature te (i), i ═ 1, 2, 3, … N, i.e., represents the internal temperature of thin-walled flat panel test model (4).
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| CN112577703A (en) * | 2020-12-23 | 2021-03-30 | 中国航天空气动力技术研究院 | Arc wind tunnel variable angle flat plate narrow gap heat flow measurement test device |
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| CN114112288A (en) * | 2021-12-23 | 2022-03-01 | 中国航天空气动力技术研究院 | Enthalpy drop measuring device and method for jet pipe of electric arc wind tunnel |
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| CN114112288A (en) * | 2021-12-23 | 2022-03-01 | 中国航天空气动力技术研究院 | Enthalpy drop measuring device and method for jet pipe of electric arc wind tunnel |
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