Dynamic and static integrated calibration device and method for radiation type high-temperature film heat flow meter

Abstract

The invention discloses a dynamic and static integrated calibration device and method for a radiation type high-temperature film heat flow meter, and relates to the technical field of aviation technology and thermophysics. A radiation system in the device is used for providing a stable radiation energy source and adjusting and converging light source radiation energy; the receiving system is used for measuring and recording heat flux density; the supporting system is provided with a radiation system and a receiving system which are adjacent. The cooling system is used for cooling the radiation system and the receiving system; the data acquisition system is responsible for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system; the dynamic test system is arranged at an outlet of the radiation system and is used for converting a direct-current heat flow signal output by the radiation system into a square-wave heat flow signal; and the data acquisition system is used for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system. According to the application, the requirements of high-temperature and high-heat-flow calibration on the aero-engine film heat flow meter can be met.

Description

Technical Field

[0001] The present application relates to the fields of aviation technology and thermal physics technology, and in particular to a dynamic and static integrated calibration device and method for a radiation-type high-temperature thin-film heat flux meter. Background Art

[0002] With the development of the aviation industry, aircraft engines are developing towards high bypass ratio, high thrust-to-weight ratio, and high turbine inlet temperature. Taking the turbine inlet temperature as an example, the fourth-generation aircraft engine is 1977K, and the future fifth-generation aircraft engine will even reach 2000-2250K. This poses a severe challenge to the thermal parameter measurement and calibration technology of the hot end components of aircraft engines. As one of the core thermal parameters, the importance of the heat flux density indicator is becoming more and more significant. Real-time monitoring of the heat flux density of each component of the aircraft engine when it is working has the functions of assisting cooling design, providing performance verification data, and improving engine thermal analysis accuracy and engine safety. Therefore, in the research and development, manufacturing and use of modern aircraft engines, the measurement of heat flux density is of great significance.

[0003] At present, there are many heat flow meter calibration devices on the market, which can be mainly divided into conductive, convection and radiation calibration devices according to their working principles. 2 For heat flow meters with frequencies higher than 1500Hz, the existing traditional calibration devices cannot meet their strict requirements for high precision and high frequency response. Summary of the invention

[0004] The purpose of this application is to provide a dynamic and static integrated calibration device and method for a radiation-type high-temperature thin-film heat flux meter, which can meet the needs of high-temperature and high-heat-flux calibration of thin-film heat flux meters for aircraft engines.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a dynamic and static integrated calibration device for a radiation-type high-temperature thin-film heat flux meter, comprising:

[0007] Radiation system, receiving system, support system, cooling system, dynamic test system and data acquisition system; the radiation system is used to provide a stable source of radiation energy, as well as to adjust and concentrate the radiation energy of the light source; the receiving system is used to measure and record the heat flux density; the support system is configured with adjacent radiation systems and receiving systems; the cooling system is used to provide cooling for the radiation system and the receiving system by water cooling or air cooling; the data acquisition system is responsible for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system; the dynamic test system is arranged at the outlet of the radiation system, and is used to convert the DC heat flow signal output by the radiation system into a square wave heat flow signal; the data acquisition system is used to collect and process data from the radiation system, the receiving system, the cooling system and the dynamic test system.

[0008] Optionally, the radiation system includes a short arc xenon lamp, an ellipsoidal reflector and an optical integrator arranged in sequence along the radiation direction; the power of the short arc xenon lamp is 3KW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of high borosilicate glass; the reflective film is a total reflection aluminum film; the ellipsoidal reflector has a first focal length of 110mm, a second focal length of 495mm, a distance between the two focal points of 385mm, a front opening of 112.10mm, and a rear opening of 457.26mm.

[0009] Optionally, the receiving system includes a high-temperature thin film heat flux meter and a standard Gordon meter arranged in sequence along the radiation direction.

[0010] Optionally, the cooling system includes a silent centrifugal fan and a water cooler; the silent centrifugal fan is arranged in the reverse radiation direction of the short arc xenon lamp to provide cooling for the short arc xenon lamp; the water cooler provides cooling for the optical integrator, the standard Gordon meter and the high temperature thin film heat flux meter respectively.

[0011] Optionally, the dynamic test system is an optical chopper; the optical chopper is arranged at the outlet of the optical integrator, and is used to convert the DC heat flow signal at the outlet of the optical integrator into a square wave heat flow signal.

[0012] Optionally, the support system includes an optical breadboard, guide rails, sliders, displacement platforms, adjustment supports, clamping devices and baffles; the optical breadboard is provided with guide rails, sliders, displacement platforms, adjustment supports, clamping devices and baffles; the guide rails, sliders, displacement platforms, adjustment supports, clamping devices and baffles are used for alignment and positioning of short arc xenon lamps, ellipsoidal reflectors and optical integrators, high temperature thin film heat flux meters, standard Gordon meters and optical choppers.

[0013] Optionally, the data acquisition system includes a DMM7510 digital multimeter, ADAM4018 and ADAM4520.

[0014] In a second aspect, the present application provides a calibration method based on the dynamic and static integrated calibration device of a radiation-type high-temperature thin-film heat flux meter, comprising:

[0015] Turn on the xenon lamp power to make the xenon lamp emit light.

[0016] The light emitted by the xenon lamp is reflected by the ellipsoidal reflector and converged at the entrance of the optical integrator.

[0017] After multiple reflections inside the optical integrator, the light forms a collimated and uniform light output.

[0018] During the static calibration process, collimated and uniform light is directly input into the high-temperature thin-film heat flux meter for static heat flux calibration; the collimated and uniform light is used to provide input heat flux with different heat flux densities for the high-temperature thin-film heat flux meter.

[0019] During the dynamic calibration process, collimated and uniform light is input into the optical chopper, and the DC heat flow signal is converted into a square wave heat flow signal based on the optical chopper, and then input into the high-temperature thin film heat flow meter for dynamic heat flow calibration.

[0020] Optionally, the heat flux density is calculated as follows:

[0021] q=C·E s .

[0023] Where q is the heat flux density, C is the probe coefficient of the thin film heat flux meter, and E S Output thermoelectric potential for thin film heat flow meter.

[0024] Optionally, the calculation formula of the thin film heat flow meter probe coefficient is specifically:

[0025]

[0026] Among them, λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 are thermal resistance layers of different materials, δ is the thickness of the thermal resistance layer, T is the surface temperature of the thermal resistance layer; N is the node, and S(T) is the Seebeck coefficient of the material.

[0027] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0028] The present application provides a dynamic and static integrated calibration device and method for a radiation-type high-temperature thin-film heat flux meter. The device consists of a radiation system, a receiving system, a support system, a cooling system, a dynamic test system and a data acquisition system. The radiation system is responsible for providing a stable radiation energy source and regulating and converging the radiation energy of the light source; the receiving system is used to measure and record the heat flux density; the support system is provided with a radiation system and a receiving system; the cooling system uses water cooling or air cooling to provide cooling for the radiation system and the receiving system; the data acquisition system is responsible for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system; the dynamic test system is located at the outlet of the radiation system, and is intended to convert the DC heat flow signal output by the radiation system into a square wave heat flow signal; the data acquisition system is used to collect and process data from the radiation system, the receiving system, the cooling system and the dynamic test system. The device described in the present application can realize the comprehensive calibration of the heat flow meter, covering static calibration and dynamic calibration. Static calibration mainly evaluates the measurement accuracy and stability of the heat flow meter, while dynamic calibration focuses on the response characteristics and measurement accuracy of the heat flow meter under changing heat flow conditions. This integrated calibration method can meet the needs of high temperature and high heat flux calibration of aircraft engine thin film heat flux meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic structural diagram of a dynamic and static integrated calibration device for a radiant high-temperature thin-film heat flux meter provided in one embodiment of the present application.

[0031] Figure 2 A schematic diagram of the ellipsoidal mirror structure provided in one embodiment of the present application.

[0032] Figure 3 A physical diagram of an optical integrator provided in one embodiment of the present application.

[0033] Figure 4 A physical picture of a silent centrifugal fan provided in one embodiment of the present application.

[0034] Figure 5 A schematic diagram of an integrator water cooling plate provided in one embodiment of the present application.

[0035] Figure 6 A schematic flow chart of a dynamic and static integrated calibration method for a radiant high-temperature thin-film heat flux meter provided in one embodiment of the present application.

[0036] Figure 7 A curve diagram of heat flux non-uniformity at an integrator outlet provided in one embodiment of the present application.

[0037] Figure 8 This is a curve chart of the static calibration results of a thin film heat flow meter provided in one embodiment of the present application.

[0038] Fig. 9 A schematic diagram of the dynamic calibration results of a thin film heat flux meter provided in one embodiment of the present application.

[0039] Fig.10 A schematic diagram of the temperature difference measurement principle of a heat flow meter provided in one embodiment of the present application.

[0040] Fig.11 Schematic diagram of a thin film heat flow meter with the same thermal resistance material and different thicknesses provided in an embodiment of the present application.

[0041] Fig.12 Schematic diagram of a thin film heat flow meter made of the same thickness but different thermal resistance materials provided in one embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] The volume of traditional heat flow meters is negligible relative to the test body, such as heat flow measurement of building envelopes, heat flow metering on the wall of fluid distribution pipelines, and heat flow metering at fire scenes. However, heat flow meters used in aircraft engines have the characteristics of high temperature, high frequency, high heat flux density, and small working space. Traditional heat flow meters are no longer applicable because of their relatively large volume, which will affect the temperature field and flow field. For such application scenarios, thin-film heat flow meters based on thermoelectric effect or thermistor temperature measurement are composed only of a sensitive layer and a thermal resistance layer. The one-dimensional Fourier law is used to calculate the heat flux through the surface of the heat flow meter. Its thickness is usually around ten microns, and it has the advantages of small size, easy installation, and fast response rate.

[0044] However, due to the complex manufacturing process of this type of thin film heat flux meter and the fact that the thermophysical properties of the material will vary to a certain extent under different conditions of use, it is difficult to ensure that the output signal under the same working conditions is completely consistent. In addition, in order to verify the effective range, temperature resistance, measurement accuracy and stability of the heat flux meter, it is usually necessary to calibrate the designed heat flux meter. Only after calibration can the heat flux meter work as a qualified test element. Therefore, in the research and development cycle of the heat flux meter, the design of the heat flux calibration is a crucial link. In addition to obtaining the performance parameters of the heat flux meter itself, the calibration results can also provide data support for the optimization of the heat flux meter structure and theoretical analysis. Therefore, in the research and development of the heat flux meter, it is particularly important to select a suitable heat flux calibration method and design a corresponding calibration device.

[0045] There are many types of calibration devices for heat flow meters, which are mainly divided into thermal conductivity calibration devices, convection calibration devices and radiation calibration devices in principle. Among them, the thermal conductivity calibration device has a small heat flux calibration range due to material limitations, and cannot perform transient calibration due to its closed structure; the convection calibration device requires a high-temperature flowing medium, which makes it difficult to accurately control the heat flux, has low calibration accuracy, and poor repeatability; the radiation calibration device can perform transient measurements, but mainly generates heat flux through equipment such as black body furnaces, and the heat flux calibration range is insufficient.

[0046] Specifically, the structures commonly used in radiation calibration platforms are as follows: absolute calibration using a variable temperature blackbody furnace or blackbody cavity as a heat source and the Stefan-Boltzman law as the basis for calculation, or relative calibration using a standard heat flux meter and a heat flux meter to be measured at the same position on the outlet; relative calibration using a focusing system to focus the radiation energy of a point light source onto the surface of the heat flux meter; relative calibration using a laser as a radiation source to design a beam expansion system so that the laser spot can cover the surface of the heat flux meter.

[0047] When using a variable temperature black body furnace for calibration, the heat flow meter cannot be placed close to the cavity outlet due to the structure of the black body furnace, thus affecting the heat flow range. The transfer method heat flow calibration equipment designed by NIST in 2000 has a maximum calibration heat flow of 50KW / ㎡ in a 25mm black body cavity. At the same time, because graphite needs to pass protective gas at high temperatures, it will inevitably introduce convection heat transfer, which will greatly affect the accuracy of the results.

[0048] For absolute heat flux calibration using a blackbody cavity, the heat flux calculation is based on the blackbody radiation theory and therefore has the characteristic of traceability. The key to its design is to improve the quality of blackbody materials, eliminate other interference factors, and apply more accurate radiation theory. Since the design of the absolute blackbody radiation method requires extremely high equipment accuracy, and requires regular calibration and extensive maintenance, only professional metrology institutions will conduct research on the absolute blackbody radiation method. In addition, the absolute blackbody radiation method heat flow range cannot meet the working conditions of the hot end components.

[0049] The main method for designing radiation calibration of the focusing system is to use a spherical mirror to focus the radiation energy emitted by the light source, and then produce a high-energy uniform light spot with an area larger than the sensor surface after homogenization. Since the sensing area of ​​the heat flux meter is small, the total radiation power will not be too large to be achieved when the heat flux density is very large. Unlike blackbody radiation, the sensor and light source of the focusing system do not need to be in direct contact, so the cooling at the light source will not bring convection effects to the surface of the heat flux meter, so that when using the relative method for calibration, it can be ensured that the standard heat flux meter and the heat flux meter to be tested are in the same radiation environment, and the radiation wavelength range emitted by the light source is large, so it can be considered that the calibration is applicable to the full spectrum range.

[0050] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0051] Embodiment 1

[0052] This embodiment provides a dynamic and static integrated calibration device for a radiation-type high-temperature thin-film heat flux meter, comprising:

[0053] Radiation system, receiving system, support system, cooling system, dynamic test system and data acquisition system; the radiation system is used to provide a stable source of radiation energy, as well as to adjust and concentrate the radiation energy of the light source; the receiving system is used to measure and record the heat flux density; the support system is configured with adjacent radiation systems and receiving systems; the cooling system is used to provide cooling for the radiation system and the receiving system by water cooling or air cooling; the data acquisition system is responsible for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system; the dynamic test system is arranged at the outlet of the radiation system, and is used to convert the DC heat flow signal output by the radiation system into a square wave heat flow signal; the data acquisition system is used to collect and process data from the radiation system, the receiving system, the cooling system and the dynamic test system.

[0054] Among them, in some embodiments, the radiation system includes a short arc xenon lamp, an ellipsoidal reflector and an optical integrator arranged in sequence along the radiation direction; the power of the short arc xenon lamp is 3KW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of high borosilicate glass; the reflective film is a total reflection aluminum film; the first focal length of the ellipsoidal reflector is 110mm, the second focal length is 495mm, the distance between the two focal points is 385mm, the front end opening is 112.10mm, and the rear end opening is 457.26mm.

[0055] Specifically, Figure 1 As shown, the light source is the source of radiation energy, and its basic requirements are easy adjustment, long working life, stable spectral characteristics without drift and no change with the power supply voltage. In addition, the closer the light source is to a point light source, the better the focusing effect can be achieved when it is combined with a reflective condenser. For this reason, the device in this embodiment selects a short arc xenon lamp as the light source of the radiation focusing system. At the same time, in order to ensure that the heat flux density at the system outlet is not less than 1MW / ㎡, the power of the xenon lamp used is 3KW.

[0056] like Figure 2 As shown, the function of the ellipsoidal reflector is to gather the radiation energy of the light source to one place. When designing the focusing reflector, the xenon lamp is regarded as a point light source at the cathode spot, and the ellipsoidal mirror is selected to gather the radiation energy of the light source. The ellipsoidal mirror is formed by rotating an ellipse around its major axis. The ellipse has a very important optical property. The light emitted from one focus of the ellipse, after being reflected by the ellipse, the reflected light intersects at the other focus of the ellipse. Therefore, the cathode spot of the short arc xenon lamp can be placed at the first focus of the ellipsoidal mirror. According to the properties of the ellipsoid, the light emitted from the cathode spot will be reflected by the ellipsoidal surface and will be gathered at the second focus. Therefore, the radiation light of the short arc xenon lamp to the surrounding space will be gathered at the second focus after being reflected by the ellipsoidal mirror. The ellipsoidal reflector is mainly composed of a substrate and a reflective film, wherein the substrate is made of high borosilicate glass, which can withstand temperatures of 300 to 400°C, and the reflective film is a fully reflective aluminum film, which can reach a reflectivity of more than 80% in the full wavelength range and more than 85% in most wavelength ranges. The first focal length F1 of the ellipsoidal mirror of this device is 110mm, the second focal length F2 is 495mm, the distance 2c between the two focal points is 385mm, the front opening D1 is 112.10mm, and the rear opening D2 is 457.26mm. At this time, the energy transfer efficiency of the ellipsoidal reflector reaches 77.04% through LightTools simulation calculation.

[0057] Among them, Figure 3As shown, the function of the integrator is to collimate the uniform light and ensure the one-dimensional uniformity of the outlet heat flux. The light emitted by the xenon lamp is reflected by the ellipsoid mirror and gathered to the second focus, but the light there is not uniformly collimated, but distributed in a disorderly cluster at different angles, and its uniformity is extremely poor, so it cannot be directly used for heat flux calibration. The channel reflection integrator can make the light achieve uniform collimation after multiple reflections on the inner wall. The optical integrator is composed of 4 high-reflectivity lenses. The reflectivity of the inner wall to the light is about 85%. Its diameter is 2cm×2cm and the depth is 130mm. At this time, the outlet heat flux unevenness of the integrator is less than 3%, and the outlet heat flux density is 1.6MW / ㎡. The outer surface of the integrator is wrapped with a water-cooled plate for cooling.

[0058] Wherein, in some embodiments, Figure 1 As shown, the receiving system includes a high-temperature thin-film heat flux meter and a standard Gordon meter which are sequentially arranged along the radiation direction.

[0059] Specifically, the receiving system is used to measure and record the heat flux density. The standard Gordon meter model is MEDTHERM 64, with a range of 0-1500kW / m 2 The coating absorption rate is 0.92, the output voltage is linearly related to the heat flux density, and the sensitivity is 0.0064mV / (kW / m 2 ). The water cooling requirements are water temperature 13℃, flow rate 13.5ml / s, and uncertainty is ±3% when the expansion factor k=2 and the confidence probability is 95%.

[0060] In some embodiments, Figure 1 As shown, the cooling system includes a silent centrifugal fan and a water cooler; the silent centrifugal fan is arranged in the reverse radiation direction of the short arc xenon lamp to provide cooling for the short arc xenon lamp; the water cooler provides cooling for the optical integrator, the standard Gordon meter and the high temperature thin film heat flux meter respectively.

[0061] Specifically, Figure 4 Shown and Figure 5 As shown, the cooling system includes: 550W silent centrifugal fan for cooling the xenon lamp. Through the special conical fan nozzle, the wind speed on the surface of the xenon lamp can reach more than 13m / s, meeting the cooling requirements of the xenon lamp; two 1.749kW water coolers provide cooling for the optical integrator and the standard Gordon meter (high-temperature thin-film heat flow meter); the optical integrator is cooled by four water-cooled plates, each of which is 13cm long and 4cm wide, respectively. It uses an M-type flow channel with a flow channel diameter of 7mm. When the xenon lamp is at maximum power, the heat flux density of the integrator takes the maximum heat flux value of 49KW / m 2 , when the inlet water temperature is 300K and the flow rate is 0.5m / s, the average temperature of the hot surface can be controlled at 32℃, meeting the cooling requirements.

[0062] In some embodiments, Figure 1 The dynamic test system is an optical chopper; the optical chopper is arranged at the outlet of the optical integrator and is used to convert the direct current heat flow signal at the outlet of the optical integrator into a square wave heat flow signal.

[0063] Specifically, when performing a frequency response test, an optical chopper is installed at the outlet of the optical integrator. The function of the optical chopper is to convert the DC heat flow signal at the outlet of the optical integrator into a square wave heat flow signal and input it into the high-temperature thin-film heat flow meter. Its heat flux density peak is the heat flux density of the DC heat flow signal, and the frequency is determined by the chopping frequency of the optical chopper. The model is Model 300CD. Depending on the selected blade disk, it can provide chopping frequencies of 5-200Hz, 12.5-500Hz, 25-1000Hz, and 75-3000Hz. The maximum phase jumps are ±0.2°, ±0.5°, ±1°, and ±3°, respectively, and the long-term frequency stability is ±0.1%×maximum frequency.

[0064] In some embodiments, Figure 1 As shown, the support system includes an optical breadboard, a guide rail, a slider, a displacement platform, an adjustment support, a clamping device and a baffle; the optical breadboard is provided with a guide rail, a slider, a displacement platform, an adjustment support, a clamping device and a baffle; the guide rail, the slider, the displacement platform, the adjustment support, the clamping device and the baffle are used for aligning and positioning a short arc xenon lamp, an ellipsoidal reflector and an optical integrator, a high temperature thin film heat flux meter, a standard Gordon meter and an optical chopper.

[0065] The data acquisition system includes a DMM7510 digital multimeter, ADAM4018 and ADAM4520.

[0066] The model of the digital multimeter is DMM7510. During static calibration, the DCV mode is used to measure DC voltage, the test NPLC ≥ 1, the range is 100mV, the resolution is 10nV, and the accuracy is ±(18ppm×reading+9ppm×range), that is, if the test signal is 1mv, the accuracy of the digital multimeter is ±(18ppm×1+9ppm×100)mV; during dynamic testing, the DigV (digital voltage) mode is used to measure the dynamic voltage signal, with a sampling rate of 1kHz, automatic aperture, an average of 100 readings cache, a range of 100mV, a resolution of 1μV, and an accuracy of ±(220ppm×reading+100ppm×range).

[0067] Embodiment 2

[0068] like Figure 6 As shown, this embodiment provides a dynamic and static integrated calibration method of a radiation type high temperature thin film heat flux meter, comprising:

[0069] Turn on the xenon lamp power to make the xenon lamp emit light.

[0070] The light emitted by the xenon lamp is reflected by the ellipsoidal reflector and converged at the entrance of the optical integrator.

[0071] After multiple reflections inside the optical integrator, the light forms a collimated and uniform light output.

[0072] During the static calibration process, collimated and uniform light is directly input into the high-temperature thin-film heat flux meter for static heat flux calibration; the collimated and uniform light is used to provide input heat flux with different heat flux densities for the high-temperature thin-film heat flux meter.

[0073] During the dynamic calibration process, collimated and uniform light is input into the optical chopper, and the DC heat flow signal is converted into a square wave heat flow signal based on the optical chopper, and then input into the high-temperature thin film heat flow meter for dynamic heat flow calibration.

[0074] The calculation formula of the heat flux is:

[0075] q=C·E s .

[0077] Where q is the heat flux density, C is the probe coefficient of the thin film heat flux meter, and E S The thin film heat flow meter outputs the thermoelectric potential. The calculation formula of the thin film heat flow meter probe coefficient is specifically:

[0078]

[0079] Among them, λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 are thermal resistance layers of different materials, δ is the thickness of the thermal resistance layer, T is the surface temperature of the thermal resistance layer; N is the node, and S(T) is the Seebeck coefficient of the material. It is determined by the thermal conductivity, thickness, number of thermopile nodes, and Seebeck coefficient of the thermal resistance layer of the thin film heat flow meter, reflecting that when the heat flow meter outputs 1V potential, a heat flux with a heat flux density of C (W / ㎡) passes vertically through the thin film heat flow meter.

[0080] That is, we get the formula

[0081] The derivation process of this formula is as follows:

[0082] First, in this embodiment, the heat flow meter calibration device has the following advantages:

[0083] ① High heat flux density: Through the ellipsoidal mirror focusing, a heat flux density of 1.64W / ㎡ can be generated at the heat flux meter with a size of 2cm×2cm.

[0084] That is, the heat flux calculation formula is

[0085] Wherein η1 is the photoelectric conversion efficiency of the xenon lamp (about 45%), η2 is the energy utilization rate of the ellipsoidal mirror (about 80%), and η3 is the energy utilization rate of the integrator (about 40% to 50%).

[0086] ②Good uniformity: By controlling the focal length of the ellipsoid mirror and the depth of the integrator, the non-uniformity of the heat flux density at the integrator outlet can be controlled within 3%. Figure 7 shown.

[0087] ③ Static-dynamic integrated calibration: This calibration device can convert static heat flow into dynamic heat flow by adding a chopper, and then calibrate the dynamic characteristics of the thin film heat flow meter, such as Figure 8 , Fig. 9 They are respectively the static and dynamic characteristics of the thin film heat flux meter calibrated on this device.

[0088] Therefore, the basic principle of thin film heat flow meter measurement is the one-dimensional Fourier law. When the heat flow passes through the surface of the heat flow meter, a temperature difference will be generated on the upper and lower surfaces of the thermal resistance layer due to the heat transfer phenomenon. Fig.10 As shown, at this time, by measuring this temperature difference in a certain way, the heat flow can be calculated according to the one-dimensional Fourier law, where the heat flow calculation formula is:

[0089]

[0090] Where q is the heat flux through the surface of the heat flow meter, λ is the thermal conductivity of the thermal resistance layer, δ is the thickness of the thermal resistance layer, and T1 and T2 are the upper and lower surface temperatures of the thermal resistance layer, respectively.

[0091] From the heat flow calculation formula, it can be seen that the key to the measurement of the thin film heat flow meter lies in the measurement of the temperature difference of the thermal resistance layer. First, in order to ensure that there is a sufficiently large temperature difference when the heat flow passes through, the thermal resistance layer is usually selected from materials with stable physical properties and large thermal resistance, such as silicon dioxide, polyimide, etc. Secondly, the accuracy of the temperature difference measurement must be guaranteed. Common methods include arranging thermosensitive materials or thin film thermocouple nodes above and below the thermal resistance layer. For the method of measuring the temperature difference using thin film thermocouple nodes, since the thickness of the thermal resistance layer is usually only at the micron level, even if a large heat flow passes through the thermal resistance layer, the temperature difference between its upper and lower surfaces is very small, resulting in an extremely small output signal of the thin film thermocouple, which is not conducive to signal collection. Therefore, a series of thin film thermocouples are usually connected in series at a position where the temperature of the thermal resistance layer is uniform, in order to achieve the purpose of amplifying the signal and reducing noise interference. The structure formed by a series of thermocouples connected in series is called a thermopile. The thermal parameters that can be measured by early thermopile thin film heat flow meters are relatively low. Its common structure is to use the upper and lower surfaces of the thermal resistance layer as the hot and cold endpoints, and arrange thermopiles (also known as sensitive layers) on them. This measurement model fully conforms to the principle of heat flow measurement. However, this structure will bring the disadvantage that the sensitive layer thin film crosses the thermal resistance layer. Whether the method of directly winding the edge of the thermal resistance layer is adopted, or the thermal resistance layer is corroded by hydrofluoric acid to connect the nodes above and below the thermal resistance layer, the problem of sensitive layer fracture or failure at high temperature will inevitably occur. In addition, improper control of hydrofluoric acid dosage will cause additional corrosion to the base material.

[0092] In order to solve the structural instability problem caused by the thermopile thin film heat flux meter crossing the thermal resistance layer, this application introduces a series of structures in which the sensitive layer is plated on the same horizontal plane by introducing reasonable assumptions. The most typical ones are the multi-thermal resistance material single thickness thin film heat flux meter and the single thermal resistance material multi-thickness thin film heat flux meter, such as Fig.11 and Fig.12 shown.

[0093] This type of thin film heat flux meter introduces two reasonable assumptions. One is that the heat flux through different thermal resistance layers of the same heat flux meter is one-dimensional and equal, and the other is that the temperature of the upper surface of different thermal resistance layers is equal. After substituting the assumptions into the heat flux calculation formula of different thermal resistance layers, the calculation formula of the heat flux of the heat flux meter can be obtained. Taking the heat flux meter with different thermal resistance layer materials of the same thickness designed by this research team as an example, its heat flux calculation formula is derived. For thermal resistance layers of the same thickness but different materials, since the heat flux passing through is equal, the one-dimensional Fourier law can be used to obtain the following formula:

[0094]

[0095] Assuming that the upper surface temperature of the thermal resistance layer is the same, there will be a temperature difference on the lower surface of the thermal resistance layer of different materials. The temperature difference calculation formula is:

[0096] ΔT=ΔT1-T2.

[0098] For thermopile thin film heat flow meters, the temperature difference is measured by the thermoelectric potential generated by the thermopile nodes. For a thermopile with N nodes, the relationship between the thermoelectric potential output and the temperature difference is:

[0099] E s =N×S(T)×ΔT.

[0101] Where: S(T) is the Seebeck coefficient of the material.

[0102] By combining the above equations, we can get the relationship between the heat flow value and the output thermoelectric potential:

[0103]

[0104] The ratio of the heat flux through the thermopile thin film heat flow meter to the output thermoelectric potential is a relationship composed of the thermal conductivity and thickness of the thermal resistance layer and the number of thermopile nodes, which is called the probe coefficient.

[0105] One of the main purposes of heat flow calibration is to obtain the probe factor or sensitivity of a heat flow meter when the heat flux through it and the output thermoelectric potential are known.

[0106] In summary, this application has the following technical effects:

[0107] This application proposes a dynamic and static integrated calibration device and method for a radiation-type high-temperature thin-film heat flux meter, which can provide 0.3MW / m 2 -1.6MW / m 2 , the input heat flux density with unevenness <3%, the static calibration relative standard uncertainty <3.10%, can meet the frequency response calibration requirements of thin film heat flux meters with cutoff frequency>1500Hz. It solves the problem that the current thin film heat flux meter calibration device can only provide low temperature and low heat flux density, and cannot be applied to the calibration requirements of high temperature, high heat flux, and high frequency response of engines and gas turbines.

[0108] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A dynamic and static integrated calibration device for a radiation-type high-temperature thin-film heat flux meter, characterized in that: The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter comprises: Radiation system, receiving system, support system, cooling system, dynamic test system and data acquisition system; the radiation system is used to provide a stable source of radiation energy, as well as to adjust and concentrate the radiation energy of the light source; the receiving system is used to measure and record the heat flux density; the support system is configured with adjacent radiation systems and receiving systems; the cooling system is used to provide cooling for the radiation system and the receiving system by water cooling or air cooling; the data acquisition system is responsible for collecting and processing data from the radiation system, the receiving system, the cooling system and the dynamic test system; the dynamic test system is arranged at the outlet of the radiation system, and is used to convert the DC heat flow signal output by the radiation system into a square wave heat flow signal; the data acquisition system is used to collect and process data from the radiation system, the receiving system, the cooling system and the dynamic test system.

2. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 1 is characterized in that: The radiation system comprises a short arc xenon lamp, an ellipsoidal reflector and an optical integrator which are sequentially arranged along the radiation direction; the power of the short arc xenon lamp is 3KW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of high borosilicate glass; the reflective film is a total reflection aluminum film; the first focal length of the ellipsoidal reflector is 110mm, the second focal length is 495mm, the distance between the two focal points is 385mm, the front end opening is 112.10mm, and the rear end opening is 457.26mm.

3. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 2 is characterized in that: The receiving system comprises a high-temperature thin-film heat flux meter and a standard Gordon meter which are sequentially arranged along the radiation direction.

4. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 3 is characterized in that: The cooling system includes a silent centrifugal fan and a water cooler; the silent centrifugal fan is arranged in the reverse radiation direction of the short arc xenon lamp to provide cooling for the short arc xenon lamp; the water cooler provides cooling for the optical integrator, the standard Gordon meter and the high temperature thin film heat flux meter respectively.

5. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 4 is characterized in that: The dynamic test system is an optical chopper; the optical chopper is arranged at the outlet of the optical integrator and is used to convert the direct current heat flow signal at the outlet of the optical integrator into a square wave heat flow signal.

6. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 5, characterized in that: The support system comprises an optical breadboard, a guide rail, a slider, a displacement platform, an adjustment support, a clamping device and a baffle; the optical breadboard is provided with a guide rail, a slider, a displacement platform, an adjustment support, a clamping device and a baffle; the guide rail, the slider, the displacement platform, the adjustment support, the clamping device and the baffle are used for aligning and positioning a short arc xenon lamp, an ellipsoidal reflector and an optical integrator, a high temperature thin film heat flux meter, a standard Gordon meter and an optical chopper.

7. The dynamic and static integrated calibration device of a radiation type high temperature thin film heat flux meter according to claim 6, characterized in that: The data acquisition system includes a DMM7510 digital multimeter, an ADAM4018 and an ADAM4520.

8. A calibration method for a dynamic and static integrated calibration device for a radiation-type high-temperature thin-film heat flux meter based on any one of claims 1 to 7, characterized in that: include: Turn on the power of the xenon lamp to make it emit light; The light emitted by the xenon lamp is reflected by the ellipsoidal reflector and converged at the entrance of the optical integrator; After multiple reflections inside the optical integrator, the light forms a collimated and uniform light output; During the static calibration process, collimated and uniform light is directly input into the high-temperature thin-film heat flow meter for static heat flow calibration; the collimated and uniform light is used to provide input heat flow with different heat flux densities for the high-temperature thin-film heat flow meter; During the dynamic calibration process, collimated and uniform light is input into the optical chopper, and the DC heat flow signal is converted into a square wave heat flow signal based on the optical chopper, and then input into the high-temperature thin film heat flow meter for dynamic heat flow calibration.

9. The calibration method according to claim 8, characterized in that: The calculation formula of the heat flux is: q=C·E s ; Where q is the heat flux density, C is the probe coefficient of the thin film heat flux meter, and E S Output thermoelectric potential for thin film heat flow meter.

10. The calibration method according to claim 9, characterized in that: The calculation formula of the probe coefficient of the thin film heat flow meter is specifically: Among them, λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 are thermal resistance layers of different materials, δ is the thickness of the thermal resistance layer, T is the surface temperature of the thermal resistance layer; N is the node, and S(T) is the Seebeck coefficient of the material.

Images