A method of transition measurement based on a plasma probe

Abstract

The application discloses a transition measurement method based on a plasma probe, wherein the plasma probe is arranged at different positions of an undisturbed part of an aircraft surface; the probe arrangement position is subjected to simulation analysis of aerodynamic heat and a temperature field in a flight process, and a probe material is selected according to a simulation result; three-dimensional plasma flow field simulation results are obtained for typical states in a transition window interval of a flight profile; three-dimensional plasma flow field electron density data are extracted, and a range of the plasma probe is determined according to the three-dimensional plasma flow field electron density data; a probe circuit is designed, and a plasma probe measurement device is obtained; the plasma probe measurement device is used to obtain a measured current-voltage curve and a saturated ion current of the probe, and electron density data are calculated according to the measured current-voltage curve and the saturated ion current, that is, a transition measurement signal of the probe plasma in the flight test, and a step change time of the transition measurement signal is taken as a transition occurrence time of measurement; according to the measured transition occurrence time, combined with telemetry data of the flight test, a transition measurement result is obtained, and validity of the transition measurement result is confirmed.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of transition measurement method based on plasma probe, belong to transition characteristic measurement field. BACKGROUND

[0002] Near space vehicle flies in the atmosphere across the flow field with extremely high speed, the gas around the vehicle is compressed severely and the temperature rises sharply, forming a strong aerodynamic heating effect on the surface of the vehicle. For the high-speed flight state of the vehicle, the thermal environment is particularly severe, after the boundary layer transition, the heat flow of the surface of the vehicle increases sharply, so the boundary layer transition is crucial for heat flow prediction and thermal protection system design. The transition process of boundary layer is influenced by many factors, and for the transition under high-speed flight, the high-temperature effect of flow field exists, and the mechanism is particularly complex. The measured data of transition based on flight test is the basis for related theoretical model research. The deficiency of the existing transition characteristic measurement method is that it mainly relies on surface heat flow to determine transition, and cannot obtain flow field component information. SUMMARY

[0003] The technical problem of the present application is to overcome the deficiencies of the prior art and provide a transition measurement method based on plasma probe, which provides a new technical means for transition measurement under high-speed flight, with high sensitivity and accurate transition time recognition.

[0004] The technical solution of the present application is: in the first aspect, a transition measurement method based on plasma probe is provided, comprising:

[0005] According to the requirement of transition research on measurement position, plasma probe is arranged at different positions of non-interference part of the surface of the vehicle;

[0006] Aerodynamic heat and temperature field simulation analysis is carried out on the probe arrangement position during flight process, to obtain the maximum temperature and stress value of the probe surface, and the probe material is selected according to the simulation results;

[0007] For typical states in transition window interval of flight profile, three-dimensional thermal chemical non-equilibrium numerical simulation of vehicle is carried out under laminar flow and turbulent flow respectively, to obtain three-dimensional plasma flow field simulation results;

[0008] According to the three-dimensional plasma flow field simulation results, three-dimensional plasma flow field electron density data is extracted for the measurement position of the probe, to determine the range of the plasma probe, and the probe circuit is designed according to the range, to obtain the plasma probe measurement device;

[0009] The measured current-voltage curve and saturated ion current of the probe are obtained by using the above plasma probe measurement device, and the electron density data is calculated according to the measured current-voltage curve and saturated ion current, i.e. the probe plasma measurement signal of flight test;

[0010] According to the probe measured near-wall region flight test probe plasma measurement signal, the step change time is taken as the measured transition occurrence time;

[0011] According to the measured transition occurrence time, combined with the flight test telemetry data, the transition measurement result is obtained, and the validity of the transition measurement result is confirmed.

[0012] Preferably, the probe electrode is made of high-temperature resistant alloy material, and the support material of the probe is made of high-temperature resistant ceramic material, and the corresponding high-temperature resistant range is 1200℃-2000℃.

[0013] Preferably, the transition measurement result includes: the flight height, speed and attack angle corresponding to the transition occurrence time of the measurement point position.

[0014] Preferably, the method for confirming the validity of the transition measurement data is: if the flight height deviation of the transition measurement result obtained by different types of sensors is within 2km, it is considered that the measurement data is valid.

[0015] The second aspect provides a transition measurement system based on plasma probe, comprising: a plasma probe measurement device, a three-dimensional plasma flow field simulation module, a transition occurrence time measurement module, and a transition measurement result verification module; wherein:

[0016] The three-dimensional plasma flow field simulation module carries out three-dimensional thermal chemical non-equilibrium numerical simulation of the aircraft under laminar flow and turbulent flow respectively for typical states in the transition window interval of the flight profile, and obtains three-dimensional plasma flow field simulation results;

[0017] The plasma probe measurement device comprises a plasma probe and a probe circuit, which is used to measure the probe measured current-voltage curve and the saturated ion current, and output them to the transition occurrence time measurement module;

[0018] The transition occurrence time measurement module uses the probe measured current-voltage curve and the saturated ion current obtained by the plasma probe measurement device, and calculates the electron density data, i.e. the flight test probe plasma measurement signal; further according to the probe measured near-wall region flight test probe plasma measurement signal, the step change time is taken as the transition occurrence time; the measured transition occurrence time is output to the transition measurement result verification module;

[0019] The transition measurement result verification module obtains the transition measurement result according to the measured transition occurrence time, combined with the flight test telemetry data, and confirms the validity of the transition measurement result.

[0020] Preferably, in the plasma probe measurement device:

[0021] The plasma probe is arranged at different positions on the non-interference part of the aircraft surface.

[0022] The probe circuit is designed according to the measurement position of the probe and the simulation result of the three-dimensional plasma flow field: the range of the plasma probe is determined by extracting the three-dimensional plasma flow field electron density data in the simulation result of the three-dimensional plasma flow field.

[0023] Preferably, the probe electrode is made of high-temperature resistant alloy material, and the support material of the probe is made of high-temperature resistant ceramic material, and the corresponding high-temperature resistant range is 1200-2000 DEG C.

[0024] Preferably, the transition measurement result includes the flight height, speed and attack angle corresponding to the occurrence time of the transition at the measurement point position.

[0025] Preferably, the method for the transition measurement result verification module to confirm the validity of the transition measurement data is: if the flight height deviation of the transition measurement result obtained by different types of sensors is within 2km, the measurement data is considered to be valid.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The present application is suitable for flow field plasma and transition measurement under the influence of complex high-temperature effect in high-speed flight conditions, can simultaneously obtain flow field plasma data and boundary layer transition characteristics, and provides a new technical means for transition measurement under high-speed flight, has high sensitivity and accurate transition time recognition.

[0028] The transition measurement method based on the flow field electron density distribution characteristics provided by the present application can be used as a comparison and verification of the traditional transition measurement, and can also obtain flow field component data (i.e. i ). BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Fig. 1 is a schematic diagram of the plasma probe device of the present application, (a) is a schematic diagram of the principle of plasma probe measurement, and (b) is a current-voltage curve measured in a certain flight test;

[0030] Figure 2 Fig. 1 is a schematic diagram of the plasma probe device of the present application, (a) is a schematic diagram of the principle of plasma probe measurement, and (b) is a current-voltage curve measured in a certain flight test; DETAILED DESCRIPTION

[0031] The present application provides a transition measurement method based on plasma probe, which provides a new means for transition measurement in high-speed flight.

[0032] (1) According to the requirement of transition research on measurement position, such as Figure 1(a) is shown, I1 is the probe electrode 1 current, I2 is the probe electrode 2 current, and I is the probe loop current; select different positions on the aircraft surface without interference to arrange the plasma probe (the circuit is inside the aircraft cabin, and only the sensitive end of the probe needs to be arranged on the surface).

[0033] (2) Perform flight process aerodynamic heat and temperature field simulation analysis on the probe arrangement position to obtain the maximum temperature and stress value of the probe surface. According to the simulation results, carry out plasma probe thermal design and strength design, and carry out probe material selection; the probe electrode is generally made of high-temperature resistant alloy material, and the support material of the probe is generally made of high-temperature resistant ceramic material, and the corresponding high-temperature resistant range is: 1200℃-2000℃.

[0034] (3) For the typical state in the transition window interval of the flight profile, carry out three-dimensional thermal chemical non-equilibrium numerical simulation of the aircraft under laminar flow and turbulent flow respectively, and obtain the three-dimensional plasma flow field simulation results.

[0035] (4) According to the simulation results in step 3, extract the three-dimensional plasma flow field electron density data for the measurement position in step 1, determine the range of the plasma probe according to the electron density data, carry out the probe circuit design according to the range, and obtain the plasma probe measurement device.

[0036] (5) Use the above plasma probe measurement device to obtain the probe measured I-V (current-voltage) curve and saturation ion current, and calculate the electron density data n i , that is, the flight test probe plasma measurement signal. The probe measured I-V (current-voltage) curve is as shown in Figure 1 (b), wherein I 1i represents the saturation ion current of the probe electrode 1, I 2i represents the saturation ion current of the probe electrode 2, and the electron density data n i The calculation formula is as follows:

[0037]

[0038] I i is the saturation ion current, m i is the air molecular weight, e is the electron charge, A is the equivalent area of the probe plasma sheath, and k is the Planck constant.

[0039] (6) According to the probe measured plasma signal, the transition time is identified, such as Figure 2The longitudinal coordinate represents the non-dimensionalized electron density data; according to the principle of probe measurement, the plasma flow field distribution (electron density data) in the near-wall region will change abruptly after the transition of the aircraft, so that the probe plasma measurement signal will have a step change; the transition time is determined according to the step change time of the probe plasma measurement signal.

[0040] (7) According to the transition time identified by the probe signal, combined with the flight test telemetry data, the transition measurement results (which can be found according to the flight time) can be obtained, including the flight height, speed, and angle of attack flight state parameters corresponding to the transition time of the measurement point position. The above results can be directly found according to the flight time.

[0041] (8) According to the transition measurement results identified by the plasma probe, combined with the data obtained by other types of sensors such as heat flow and vibration, the effectiveness of the transition measurement data is confirmed. The method for confirming the effectiveness of the transition measurement data is: if the flight height deviation of the transition measurement results obtained by different types of sensors is within 2km, the measurement data is considered effective.

[0042] In a second aspect, the present application provides a transition measurement system based on a plasma probe, comprising: a plasma probe measurement device, a three-dimensional plasma flow field simulation module, a transition time measurement module, and a transition measurement result verification module; wherein:

[0043] The three-dimensional plasma flow field simulation module carries out three-dimensional thermal chemical non-equilibrium numerical simulation of the aircraft under typical states in the transition window interval of the flight profile, respectively under laminar flow and turbulent flow, to obtain three-dimensional plasma flow field simulation results;

[0044] The plasma probe measurement device comprises a plasma probe and a probe circuit, which is used to measure the probe actual current-voltage curve and the saturation ion current, and outputs them to the transition time measurement module;

[0045] The transition time measurement module uses the probe actual current-voltage curve and the saturation ion current obtained by the plasma probe measurement device, and calculates the electron density data, i.e. the flight test probe plasma measurement signal; further, according to the probe actual current-voltage curve and the saturation ion current, the step change time of the probe plasma measurement signal in the near-wall region is used as the transition time; the measured transition time is output to the transition measurement result verification module;

[0046] The transition measurement result verification module obtains the transition measurement results according to the measured transition time, combined with the flight test telemetry data, and confirms the effectiveness of the transition measurement results.

[0047] In the plasma probe measurement device:

[0048] The plasma probe is arranged at different positions on the non-interference part of the surface of the aircraft;

[0049] The probe circuit is designed according to the measurement position of the probe and the three-dimensional plasma flow field simulation result: the range of the plasma probe is determined by extracting the three-dimensional plasma flow field electron density data in the three-dimensional plasma flow field simulation result.

[0050] The probe electrode is made of high-temperature resistant alloy material, and the support material of the probe is made of high-temperature resistant ceramic material, and the corresponding high-temperature resistant range is 1200 DEG C to 2000 DEG C.

[0051] The transition measurement result includes: the flight height, speed and attack angle corresponding to the occurrence time of the transition at the measurement point position.

[0052] The method for the transition measurement data validity confirmation of the transition measurement result verification module is: if the flight height deviation of the transition measurement result obtained by the different types of sensors is within 2km, the measurement data is considered to be effective.

[0053] The contents not described in detail in the specification of the present application belong to the prior art known to the person skilled in the art.

Claims

1. A method of transition measurement based on a plasma probe, characterised in that The method comprises the following steps: According to the requirements of the transition research on the measurement position, the plasma probe is arranged at different positions of the non-interference part of the aircraft surface; The aerodynamic heating and temperature field simulation analysis is carried out on the probe arrangement position during the flight process, and the maximum temperature and stress value of the probe surface are obtained, and the probe material is selected according to the simulation results; The three-dimensional thermal chemical non-equilibrium numerical simulation of the aircraft is carried out under the laminar flow and turbulent flow states respectively for the typical states in the transition window interval of the flight profile, and the three-dimensional plasma flow field simulation results are obtained; According to the three-dimensional plasma flow field simulation results, the three-dimensional plasma flow field electron density data is extracted for the measurement position of the probe, and the range of the plasma probe is determined according to the range, the probe circuit is designed according to the range, and the plasma probe measurement device is obtained; The measured current-voltage curve and the saturation ion current of the probe are obtained by using the above plasma probe measurement device, and the electron density data, i.e. the probe plasma measurement signal of the flight test, is calculated; According to the measured near-wall region flight test probe plasma measurement signal of the probe, the step change time is taken as the measurement transition occurrence time; According to the measured transition occurrence time, the transition measurement result is obtained in combination with the flight test telemetry data, and the validity of the transition measurement result is confirmed.

2. A method of transition measurement based on a plasma probe according to claim 1, characterised in that: The probe electrode is made of high-temperature resistant alloy material, and the support material of the probe is made of high-temperature resistant ceramic material, and the corresponding high-temperature resistant range is 1200-2000 DEG C.

3. A method of transition measurement based on a plasma probe according to claim 1, characterised in that: The transition measurement result includes the flight height, speed and attack angle corresponding to the transition occurrence time of the measurement point position.

4. A method of transition measurement based on a plasma probe according to claim 1, characterized in that: The method for confirming the validity of the transition measurement data is that if the flight height deviation of the transition measurement result obtained by different types of sensors is within 2km, the measurement data is considered to be valid.

5. A plasma probe based transition measurement system characterised in that The method comprises the following steps: The plasma probe measurement device, the three-dimensional plasma flow field simulation module, the transition occurrence time measurement module and the transition measurement result verification module are included, wherein: The three-dimensional plasma flow field simulation module carries out three-dimensional thermal chemical non-equilibrium numerical simulation of the aircraft under laminar flow and turbulent flow states respectively for the typical states in the transition window interval of the flight profile, and obtains three-dimensional plasma flow field simulation results; The plasma probe measurement device comprises a plasma probe and a probe circuit, which is used to measure the measured current-voltage curve and the saturation ion current of the probe, and outputs the same to the transition occurrence time measurement module; The transition occurrence time measurement module uses the measured current-voltage curve and the saturation ion current of the probe obtained by the plasma probe measurement device, and calculates the electron density data, i.e. the probe plasma measurement signal of the flight test; further according to the measured near-wall region flight test probe plasma measurement signal of the probe, the step change time is taken as the transition occurrence time; the measured transition occurrence time is output to the transition measurement result verification module; The transition measurement result verification module obtains the transition measurement result in combination with the flight test telemetry data according to the measured transition occurrence time, and confirms the validity of the transition measurement result.

6. A plasma probe based transition measurement system according to claim 5, characterised in that: In the plasma probe measurement device: The plasma probe is arranged at different positions of the non-interference part of the aircraft surface; The probe circuit is designed according to the measurement position of the probe and the simulation result of the three-dimensional plasma flow field; the range of the plasma probe is determined by extracting the three-dimensional plasma flow field electron density data in the simulation result of the three-dimensional plasma flow field.

7. A plasma probe based transition measurement system according to claim 5, characterised in that: The probe electrode is made of high-temperature-resistant alloy material, and the support material of the probe is made of high-temperature-resistant ceramic material, and the corresponding high-temperature-resistant range is 1200-2000 DEG C.

8. A plasma probe based transition measurement system according to claim 5, wherein: The transition measurement result includes the flight height, speed and attack angle corresponding to the time when the transition occurs at the measurement point position.

9. A plasma probe based transition measurement system according to claim 5, characterised in that: The method for confirming the validity of the transition measurement data by the transition measurement result verification module is that if the flight height deviation of the transition measurement result obtained by different types of sensors is within 2 km, the measurement data is considered valid.

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