A device for measuring viscosity of gas in an extremely high temperature environment

Abstract

An extreme high-temperature environment gas viscosity measuring device, comprising a composite multi-layer main temperature field control device and a variable-diameter acoustic wave guide acoustic signal measuring device; wherein the composite multi-layer temperature control device comprises a high-temperature furnace, a high-temperature heat pipe, a vacuum constant temperature layer, an experimental cavity, a temperature measuring sensor, a first resistance heating sheet, a second resistance heating sheet and quartz wool; the temperature measuring component is arranged on the wall of the experimental cavity; the experimental cavity is provided with acoustic wave guide openings on both sides; the heating and temperature control component is arranged outside the experimental cavity; the variable-diameter acoustic wave guide acoustic signal measuring component comprises a small-diameter guide pipe, a medium-diameter guide pipe, a large-diameter guide pipe, a sealing diaphragm, an acoustic sensor and a pressure measuring branch pipe; the pressure measuring pipe is connected with the variable-diameter acoustic wave guide acoustic signal measuring component through the pressure measuring branch pipe and is further connected with the experimental cavity.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of extreme high temperature environment gas viscosity measuring device, it is related to gas thermophysical property measurement field. BACKGROUND

[0002] When super-speed aircraft flies in atmosphere, it experiences extremely severe high temperature aerodynamic heating environment, and accurate extreme high temperature atmospheric environment thermophysical property parameter is the important basis for the aerodynamic force of high-speed aircraft, aerodynamic heating environment prediction, and its prediction precision directly affects the aerodynamic design of aircraft and the accurate prediction of aerodynamic environment.High-temperature atmospheric property parameter deviation directly leads to flight thermal environment prediction and real flight state presents different degrees of " deviation ".The lack of high-precision high-temperature atmospheric property becomes one of the key bottlenecks restricting the accurate prediction of super-speed aircraft aerodynamic thermal environment.Air viscosity is an important atmospheric property parameter, is the key control parameter of aircraft near-wall disturbance boundary layer, and is one of the fundamental reasons for aerodynamic heating of super-speed aircraft.The accurate high-temperature atmospheric viscosity characteristics of extreme high temperature are urgently needed for super-speed aircraft flight thermal environment prediction.

[0003] Experimental research is the most direct and most accurate method to obtain the basic data of working medium viscosity and other thermophysical properties.At present, the gas viscosity calculation method in the research of aircraft aerodynamic heat and aerodynamic force is mostly the empirical engineering correlation formula based on the research of space shuttle reentry in the 1960s, but it is difficult to meet the accurate aerodynamic thermal research needs of new high-speed aircraft, and it is urgent to carry out the measurement of atmospheric viscosity in extreme high temperature environment.

[0004] Most of the existing gas viscosity measurement methods are developed based on low-viscosity liquid viscosity measurement, and the methods that can realize high-precision gas viscosity measurement mainly include vibrating disc method, vibrating string method, capillary method, rotation method, etc., which obtain gas viscosity by measuring the shear force between the gas to be measured and the container wall or the vibrating body.However, these methods are only suitable for normal temperature environment, and it is difficult to adapt to the measurement of atmospheric viscosity in extreme high temperature environment in terms of measurement range, measurement precision and application range, etc.Therefore, it is necessary to establish an accurate measurement experimental device suitable for gas viscosity in extreme high temperature environment. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and solve the problem of gas viscosity measurement in extreme high temperature environment.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] A kind of extreme high temperature environment gas viscosity measuring device, including composite multilayer main temperature field control device, and two variable-diameter acoustic waveguide acoustic signal measurement devices;

[0008] The composite multi-layer main temperature field control device comprises a high-temperature furnace, a high-temperature heat pipe, a vacuum constant temperature layer, an experimental cavity, a temperature measuring sensor, a resistance heating sheet and quartz wool.

[0009] Each variable-diameter acoustic wave guide acoustic signal measuring device comprises a small-diameter guide pipe, a medium-diameter guide pipe and a large-diameter guide pipe connected in sequence, and a film and an acoustic sensor installed at one end of the large-diameter guide pipe; one of the variable-diameter acoustic wave guide acoustic signal measuring devices further comprises a pressure measuring branch pipe installed on the side of the large-diameter guide pipe and in communication with the large-diameter guide pipe, and a pressure measuring sensor installed at one end of the pressure measuring branch pipe.

[0010] The small-diameter guide pipe passes through the acoustic wave guide opening, so that the variable-diameter acoustic wave guide acoustic signal measuring device can measure the acoustic signal in the resonance cavity, and then obtain the gas viscosity.

[0011] Preferably, the high-temperature furnace is a horizontal muffle furnace.

[0012] Preferably, the high-temperature heat pipe is a high-temperature heat pipe filled with rare metals.

[0013] Preferably, the vacuum constant temperature layer is filled with non-corrosive inert gas.

[0014] Preferably, the device further comprises a control module for controlling the composite multi-layer main temperature field control device, and the temperature control mode of the control module is:

[0015] T(t) = P[ΔT(t) + I∫ΔT(t)dt] + T c

[0016] wherein T(t) is the temperature control value, ΔT(t) is the deviation of the temperature at time t from the target temperature, P and I are control parameters, wherein P is the constant of the proportional term, I is the constant of the integral term, T is the temperature control constant, and t is time. c

[0017] Preferably, the measuring device can simulate a maximum temperature exceeding 1000K.

[0018] Preferably, the temperature field uniformity in the measuring device is less than 5K.

[0019] ​Preferably, the temperature measuring sensor is a platinum-rhodium thermocouple.

[0020] Preferably, in the extreme high-temperature environment simulation, heating is first performed, when the preset temperature is reached, vacuum is performed, and finally temperature control is performed.

[0021] Preferably, the acoustic sensor is used to measure the resonance peak of the acoustic signal, obtain the resonance peak half-width change value caused by the gas viscosity dissipation, and further obtain the gas viscosity at high temperature.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] (1) The present application can effectively avoid the shortcomings of the traditional measurement device method, can realize high-precision measurement of gas viscosity in an extreme high-temperature environment above 1000K, has the advantages of high applicable temperature range, wide measurement range, high automation degree, etc., and is suitable for measurement of gas thermophysical properties, especially high-temperature gas thermophysical properties;

[0024] (2) The present application uses an acoustic wave guide to transmit acoustic signals to a normal-temperature environment, and uses an acoustic sensor to measure the acoustic signals, so that acoustic signal measurement in a high-temperature environment can be realized in a normal-temperature environment, and commercial sensors can obtain acoustic signal characteristics in a resonance cavity in a high-temperature environment;

[0025] (3) The present application uses a variable-diameter acoustic wave guide to transmit acoustic signals, and uses a small-diameter guide tube at the connection end of the resonance cavity, which reduces the disturbance of the acoustic wave guide to the internal sound field of the resonance cavity, and realizes high signal-to-noise ratio measurement of acoustic signals;

[0026] (4) The present application uses a combination of a sealing diaphragm and a piezoelectric ceramic to form an acoustic sensor, which maintains the stability of the gas in the cavity, avoids the influence of gas leakage caused by sensor installation, and eliminates the disturbance of gas flow to the sound field and acoustic signals in the cavity;

[0027] (5) The present application realizes a high-uniformity, high-stability high-temperature environment of 1000K and above by using an active and passive composite multi-layer temperature control method, and the temperature field uniformity is less than 5K. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a composite multi-layer main temperature control field control component.

[0029] Figure 2 It is a variable-diameter acoustic wave guide acoustic signal measurement component DETAILED DESCRIPTION

[0030] To make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0031] The application provides an extreme high-temperature environment gas viscosity measuring device, through which high-precision measurement of gas viscosity in an extreme high-temperature environment can be realized, and specifically comprises: a composite multi-layer main temperature field control device and a variable-diameter acoustic wave guide tube acoustic signal measuring device; wherein the composite multi-layer temperature control device comprises a high-temperature furnace 1, a high-temperature heat pipe 2, a vacuum constant temperature layer 3, an experimental cavity 4, a temperature measuring sensor 5, a first resistance heating sheet 6, a second resistance heating sheet 7 and quartz wool 8, wherein the temperature measuring component is arranged on the wall surface of the experimental cavity, wherein the experimental cavity is provided with acoustic wave guide tube openings on both sides, and the heating temperature control component is arranged outside the experimental cavity; wherein the variable-diameter acoustic wave guide tube acoustic signal measuring component comprises a small-diameter guide pipe 9, a medium-diameter guide pipe 10, a large-diameter guide pipe 11, a sealing diaphragm 12, an acoustic sensor 13, a pressure measuring branch pipe 14 and a pressure measuring sensor 15, the pressure measuring pipe is connected with the variable-diameter acoustic wave guide tube acoustic signal measuring component through the pressure measuring branch pipe, and is further connected with the experimental cavity. Figure 1 Figure 2

[0032]

[0033]

[0034]

[0035]

[0036] The extreme high-temperature environment gas viscosity measuring device realizes high-stability high-temperature environment through a composite multi-layer active temperature field control component. First, a high-temperature furnace provides a preliminary high-temperature environment, wherein the high-temperature furnace 1 generates an initial high-temperature environment, and preferably, the high-temperature furnace is a horizontal muffle furnace; the high-temperature heat pipe 2 further improves temperature stability, and the high-temperature heat pipe is a high-temperature heat pipe filled with a rare metal, and preferably, the filled metal is sodium. The vacuum constant temperature layer 3 is a double-layer vacuum pipe made of a high-temperature alloy, in a heating and temperature rising process, the vacuum constant temperature layer 3 is filled with a non-corrosive gas, and preferably, the non-corrosive gas is nitrogen; when the temperature measuring sensor 5 measures that the temperature rises to a set temperature, such as 1000K, the vacuum constant temperature layer 3 is subjected to vacuumizing treatment, and preferably, the temperature sensor 5 is a platinum-rhodium thermocouple. After the vacuumizing ends, the outer temperature control of the experimental cavity 4 and the vacuum constant temperature layer 3 is started, and the temperature control strategy is controlled as follows:

[0037] T(t) = P [ΔT(t) + I∫ΔT(t)dt] + T c (1)

[0038] ​​​​​​Wherein, T(t) is the temperature value at t time, ΔT(t) = T(t) - T set is the deviation of the temperature at t time and the target temperature, T set is the target temperature value, P, I are control parameters, wherein P is the proportional term constant, such as 100, I is the integral term constant, such as 20, T c is the temperature control constant, such as 5, and t is the time. The temperature control of the resistance heating layer is realized by respectively controlling the heating current of the first resistance heating sheet 6 and the second resistance heating sheet 7 through the programmable control current source.

[0039] The composite multi-layer active temperature field control component fills the gap between the high-temperature heat pipe 2, the vacuum constant temperature layer 3 and the experimental cavity 4 in the high-temperature furnace with quartz wool 8 for heat preservation, so as to realize a high-stability high-temperature heat environment for the experimental cavity.

[0040] An extreme high-temperature environment gas viscosity measuring component realizes high signal-to-noise ratio measurement of acoustic signals in a normal temperature environment under a high-temperature environment through a variable-diameter acoustic waveguide acoustic signal measuring component, reduces the disturbance to the acoustic field in the cavity, and solves the problem that commercial acoustic sensors are not suitable for high-temperature environments. First, the acoustic sensor 13, preferably a piezoelectric ceramic, generates an acoustic signal excitation through the sealing film 12. The acoustic signal is transmitted into the experimental cavity through three acoustic waveguides. The acoustic signal in the experimental cavity is coupled through the acoustic waveguide at the other end and transmitted to the acoustic sensor on this side through the acoustic waveguide for measurement. The preferred acoustic waveguide structure is a three-section structure, wherein the diameter is the smallest near the experimental cavity, so as to ensure high signal-to-noise ratio of the acoustic signal in the transmission process and reduce the disturbance to the acoustic resonance signal in the cavity. By measuring the resonance peak of the acoustic signal, the change value of the resonance peak half-width caused by the gas viscosity dissipation is obtained, and the gas viscosity at high temperature is obtained.

[0041] Wherein, the pressure sensor 15 measures the pressure of the gas to be measured in the cavity through the pressure measuring branch pipe 14.

[0042] Wherein, the temperature measuring sensor 5 measures the temperature of the gas to be measured in the experimental cavity in a stable state.

[0043] Therefore, the composite multi-layer active temperature field control component and the variable-diameter acoustic waveguide acoustic signal measuring component of the present application establish a gas viscosity measuring device suitable for extreme high-temperature environments.

[0044] The contents not described in detail in the specification of the present application are the known technology of those skilled in the art.

[0045] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application shall fall within the protection scope of the technical solutions of the present application.

Claims

1. A gas viscosity measuring device for extreme high-temperature environments, characterized in that, The composite multilayer main temperature field control device and two variable-diameter acoustic waveguide acoustic signal measurement devices are included. The composite multilayer main temperature field control device includes a high-temperature furnace, a high-temperature heat pipe, a vacuum constant temperature layer, an experimental cavity, a temperature measurement sensor, a resistance heating sheet, and quartz wool. The resistance heating sheet is tightly installed on the outer wall of the experimental cavity, and the resistance heating sheet and the experimental cavity are located in the vacuum constant temperature layer as a whole. The high-temperature heat pipe is located outside the vacuum constant temperature layer, and the high-temperature furnace is located outside the high-temperature heat pipe. The experimental cavity is provided with two resonance cavities and a capillary conduit connecting the two resonance cavities. The temperature measurement sensor is located in the wall of the experimental cavity and at the capillary conduit. The two resonance cavities are respectively provided with acoustic waveguide openings. The gaps between the high-temperature heat pipe and the vacuum constant temperature layer and between the vacuum constant temperature layer and the experimental cavity are filled with high-temperature-resistant quartz wool. During the heating process, the vacuum constant temperature layer is filled with non-corrosive gas, and the vacuum constant temperature layer is subjected to vacuum treatment when the temperature measurement sensor measures that the temperature reaches the set temperature. Each variable-diameter acoustic waveguide acoustic signal measurement device includes a small-diameter conduit, a medium-diameter conduit, and a large-diameter conduit connected in sequence, and a film and an acoustic sensor installed at one end of the large-diameter conduit. One of the variable-diameter acoustic waveguide acoustic signal measurement devices further includes a pressure measurement branch pipe installed on the side of the large-diameter conduit and in communication with the large-diameter conduit, and a pressure measurement sensor installed at one end of the pressure measurement branch pipe. The small-diameter conduit passes through the acoustic waveguide opening, so that the variable-diameter acoustic waveguide acoustic signal measurement device can measure the acoustic signal in the resonance cavity, and then obtain the gas viscosity.

2. The measuring device of claim 1, wherein, The high-temperature furnace is a horizontal muffle furnace.

3. The measuring device of claim 1, wherein, The high-temperature heat pipe is a high-temperature-resistant heat pipe filled with rare metals.

4. The measuring device of claim 1, wherein, The vacuum constant temperature layer is filled with non-corrosive inert gas.

5. The measuring device of claim 1, wherein, A control module is further included for controlling the composite multilayer main temperature field control device. The temperature control mode of the control module is as follows: wherein is a temperature control value, is t is a deviation of the momentary temperature from the target temperature, P , I is a control parameter, wherein P is a proportional term constant, I is an integral term constant, is a temperature control constant, t is time.

6. The measuring device according to any one of claims 1 to 5, characterized in that The highest temperature that can be simulated by the measurement device exceeds 1000 K.

7. The measuring device according to any one of claims 1 to 5, characterized in that The temperature field uniformity in the measurement device is less than 5 K.

8. The measuring device according to any one of claims 1 to 5, characterized in that The temperature measurement sensor is a platinum-rhodium thermocouple.

9. The measuring device according to any one of claims 1 to 5, characterized in that, The resonance peak of the acoustic signal is measured by the acoustic sensor, the resonance peak half-width change value caused by the gas viscosity dissipation is obtained, and then the gas viscosity at high temperature is obtained.

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