Radiation type high temperature thin film heat flow meter dynamic and static integrated calibration device and method

Abstract

The application discloses a radiation type high-temperature thin-film heat flow meter dynamic-static integrated calibration device and method, relates to the technical field of aviation and thermophysics, and the device is characterized in that: a radiation system is used for providing a stable radiation energy source and adjusting and converging light source radiation energy; a receiving system is used for measuring and recording heat flow density; adjacent radiation systems and receiving systems are arranged on a support system; a cooling system is used for providing cooling for the radiation systems and the receiving system; a data acquisition system is responsible for collecting and processing data from the radiation systems, the receiving systems, the cooling system and a 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 systems, the receiving systems, the cooling system and the dynamic test system, so that the application can meet the demand for high-temperature and high-heat flow calibration of an aero-engine thin-film heat flow meter.

Description

Technical Field

[0001] This application relates to the fields of aerospace technology and thermophysics, and in particular to a dynamic and static integrated calibration device and method for a radiation-type high-temperature thin-film heat flow meter. Background Technology

[0002] With the development of the aviation industry, aero-engines are evolving towards higher bypass ratios, higher thrust-to-weight ratios, and higher turbine inlet temperatures. For example, the turbine inlet temperature for fourth-generation aero-engines is 1977K, and future fifth-generation aero-engines may even reach 2000-2250K. This poses a severe challenge to the measurement and calibration technology of thermal parameters for hot-end components of aero-engines. As one of the core thermal parameters, heat flux density is becoming increasingly important. Real-time monitoring of the heat flux density of various components during aero-engine operation assists in cooling design, provides performance verification data, improves the accuracy of engine thermal analysis, and enhances engine safety. Therefore, the measurement of heat flux density is of paramount importance in the research, development, manufacturing, and use of modern aero-engines.

[0003] Currently, various heat flux meter calibration devices are available on the market, which can be mainly classified into thermal conductivity, convection, and radiation types based on their working principles. However, for heat flux meters used in aero engines, such as those with heat flux densities exceeding 1 MW / m³, specific calibration methods are required. 2 For heat flow meters with frequencies higher than 1500Hz, existing traditional calibration devices cannot meet their stringent 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 flow meter, which can meet the requirements for high-temperature and high-heat-flow calibration of thin-film heat flow meters for aero-engines.

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

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

[0007] The system comprises a radiation system, a receiving system, a support system, a cooling system, a dynamic testing system, and a data acquisition system. The radiation system provides a stable source of radiant energy and regulates and focuses the radiant energy. The receiving system measures and records heat flux density. Adjacent radiation and receiving systems are mounted on the support system. The cooling system provides cooling to the radiation and receiving systems using water or air cooling. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The dynamic testing system, located at the outlet of the radiation system, converts the DC heat flux signal output by the radiation system into a square wave heat flux signal. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems.

[0008] Optionally, the radiation system includes a short-arc xenon lamp, an ellipsoidal reflector, and an optical integrator arranged sequentially along the radiation direction; the short-arc xenon lamp has a power of 3KW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of 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 focal distance 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 flow meter and a standard Gordon meter arranged sequentially along the radiation direction.

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

[0011] Optionally, the dynamic testing system is an optical chopper; the optical chopper is located 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, a guide rail, a slider, a displacement platform, an adjusting support, a clamping device, and a baffle; the optical breadboard is provided with the guide rail, slider, displacement platform, adjusting support, clamping device, and baffle; the guide rail, slider, displacement platform, adjusting support, clamping device, and baffle are used for the alignment and positioning of the short-arc xenon lamp, ellipsoidal reflector and optical integrator, high-temperature thin-film heat flow meter, standard Gordon meter, and optical chopper.

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

[0014] Secondly, this application provides a calibration method based on the aforementioned integrated dynamic and static calibration device for a radiation-type high-temperature thin-film heat flux meter, comprising:

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

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

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

[0018] 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 the high-temperature thin-film heat flow meter with input heat flow of different heat flow densities.

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

[0020] Optionally, the formula for calculating the heat flux density is:

[0021] q = C·E s

[0022] Where q is the heat flux density, C is the probe coefficient of the thin-film heat flux meter, and E S The output thermoelectric potential is used for thin-film heat flow meters.

[0023] Optionally, the formula for calculating the probe coefficient of the thin-film heat flow meter is as follows:

[0024]

[0025] Where λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 represent thermal resistance layers made 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.

[0026] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0027] This application provides an integrated static and dynamic calibration device and method for a radiation-type high-temperature thin-film heat flux meter. The device comprises a radiation system, a receiving system, a support system, a cooling system, a dynamic testing system, and a data acquisition system. The radiation system provides a stable radiation energy source and regulates and concentrates the radiation energy. The receiving system measures and records the heat flux density. The support system houses both the radiation and receiving systems. The cooling system uses water or air cooling to cool the radiation and receiving systems. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The dynamic testing system, located at the outlet of the radiation system, converts the DC heat flux signal output by the radiation system into a square wave heat flux signal. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The device described in this application enables comprehensive calibration of the heat flux meter, covering both static and dynamic calibration. Static calibration primarily evaluates the measurement accuracy and stability of the heat flux meter, while dynamic calibration focuses on the response characteristics and measurement accuracy of the heat flux meter under varying heat flux conditions. This integrated calibration method can meet the requirements for high-temperature, high-heat-flow calibration of thin-film heat flow meters for aero-engines. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a dynamic and static integrated calibration device for a radiation-type high-temperature thin-film heat flow meter, provided as an embodiment of this application.

[0030] Figure 2 This is a schematic diagram of an ellipsoidal mirror structure provided in an embodiment of this application.

[0031] Figure 3 A physical diagram of an optical integrator provided in an embodiment of this application.

[0032] Figure 4 A physical image of a silent centrifugal fan provided in one embodiment of this application.

[0033] Figure 5 This is a schematic diagram of an integrator water-cooled plate provided in an embodiment of this application.

[0034] Figure 6 This is a schematic flowchart of a dynamic and static integrated calibration method for a radiation-type high-temperature thin-film heat flow meter provided in one embodiment of this application.

[0035] Figure 7 A graph showing the non-uniformity of heat flux density at the integrator outlet provided in an embodiment of this application.

[0036] Figure 8 A graph showing the static calibration results of a thin-film heat flow meter provided in an embodiment of this application.

[0037] Figure 9 This is a schematic diagram of the dynamic calibration results of a thin-film heat flow meter provided in an embodiment of this application.

[0038] Figure 10 This is a schematic diagram illustrating the principle of heat flow meter temperature difference measurement in one embodiment of this application.

[0039] Figure 11 This is a schematic diagram of a thin-film heat flow meter with the same thermal resistance material but different thicknesses, provided as an embodiment of this application.

[0040] Figure 12 This is a schematic diagram of a thin-film heat flow meter with the same thickness but different thermal resistance materials provided in an embodiment of this application. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Traditional heat flow meters are negligible in size relative to the test object, such as for heat flow measurement in building envelopes, heat flow measurement on the walls of fluid distribution networks, and heat flow measurement in fire situations. However, heat flow meters used in aero-engines are characterized by high temperature, high frequency, high heat flux density, and limited working space. Traditional heat flow meters are no longer suitable because their relatively large size would affect the temperature and flow fields. For such applications, thin-film heat flow meters, which rely on thermoelectric effects or thermistor temperature measurement, consist of only a sensitive layer and a thermal resistance layer. They calculate the heat flow through the surface of the heat flow meter using one-dimensional Fourier law. Their thickness is typically around ten micrometers, offering advantages such as small size, easy installation, and fast response rate.

[0043] Thin-film heat flow meters, due to their complex manufacturing process and the inherent variations in material thermophysical properties under different operating conditions, present challenges in ensuring consistent signal output under uniform conditions. Furthermore, calibration is typically required to verify the effective range, temperature resistance, measurement accuracy, and stability of the heat flow meter. Only after calibration can a heat flow meter function as a qualified test element. Therefore, heat flow calibration is a crucial step in the heat flow meter development cycle. The calibration results not only provide the meter's performance parameters but also offer data support for structural optimization and theoretical analysis. Thus, selecting a suitable heat flow calibration method and designing a corresponding calibration device are paramount in heat flow meter development.

[0044] There are many types of calibration devices for heat flow meters, which can be mainly classified into thermally conductive calibration devices, convection calibration devices, and radiation calibration devices based on their principles. Among them, thermally conductive calibration devices have a small heat flow calibration range due to material limitations, and their closed structure makes transient calibration impossible; convection calibration devices require a high-temperature flowing medium, making it difficult to accurately control the magnitude of heat flow, resulting in low calibration accuracy and poor repeatability; radiation calibration devices can perform transient measurements, but they mainly generate heat flow through equipment such as blackbody furnaces, resulting in insufficient heat flow calibration range.

[0045] Specifically, the structures commonly used in radiation calibration platforms include the following: absolute calibration using a variable-temperature blackbody furnace or blackbody cavity as the heat source and the Stefan-Bolzman law as the basis for calculation; relative calibration using a standard heat flow meter and the heat flow meter under test placed at the same position at the outlet; relative calibration using a focusing system to concentrate the radiation energy of a point source onto the surface of the heat flow meter; and relative calibration using a laser as the radiation source and a beam expanding system designed so that the laser spot can cover the surface of the heat flow meter.

[0046] When using a variable-temperature blackbody furnace for calibration, the heat flux meter cannot be placed close to the cavity outlet due to the furnace's structure, thus affecting the heat flux range. The transfer-based heat flux calibration device designed by NIST in 2000 had a maximum calibration heat flux of 50 kW / m² within a 25 mm blackbody cavity. Furthermore, because graphite requires a protective gas at high temperatures, convective heat transfer is inevitably introduced, significantly impacting the accuracy of the results.

[0047] For absolute heat flux calibration using a blackbody cavity, the heat flux calculation is traceable because it is based on blackbody radiation theory. The key to its design lies in improving the quality of the blackbody material, eliminating other interfering factors, and applying more accurate radiation theories. Because the design of the blackbody radiation absolute method requires extremely high equipment precision, as well as regular calibration and extensive maintenance, only specialized metrology institutions conduct research on this method. Furthermore, the heat flux range of the blackbody radiation absolute method cannot meet the operating conditions of hot-end components.

[0048] The main method for radiometric calibration of a focusing system is to concentrate the radiation energy emitted by the light source using a spherical mirror, and then homogenize it to produce a high-energy uniform light spot with an area larger than the sensor surface. Because the heat flux meter has a small sensing area, the total radiated power will not be prohibitively high even with high heat flux density. Unlike blackbody radiation, the sensor and light source in a focusing system do not need to be in direct contact. Therefore, cooling at the light source will not cause convection effects on the heat flux meter surface. This ensures that the standard heat flux meter and the heat flux meter under test are in the same radiation environment when using the relative calibration method. Furthermore, the light source emits radiation with a wide wavelength range, making the calibration applicable across the entire spectrum.

[0049] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] This embodiment provides an integrated dynamic and static calibration device for a radiation-type high-temperature thin-film heat flow meter, comprising:

[0052] The system comprises a radiation system, a receiving system, a support system, a cooling system, a dynamic testing system, and a data acquisition system. The radiation system provides a stable source of radiant energy and regulates and focuses the radiant energy. The receiving system measures and records heat flux density. Adjacent radiation and receiving systems are mounted on the support system. The cooling system provides cooling to the radiation and receiving systems using water or air cooling. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The dynamic testing system, located at the outlet of the radiation system, converts the DC heat flux signal output by the radiation system into a square wave heat flux signal. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems.

[0053] In some embodiments, the radiation system includes a short-arc xenon lamp, an ellipsoidal reflector, and an optical integrator arranged sequentially along the radiation direction; the short-arc xenon lamp has a power of 3 kW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of borosilicate glass; the reflective film is a total reflection aluminum film; the ellipsoidal reflector has a first focal length of 110 mm, a second focal length of 495 mm, a focal distance of 385 mm, a front opening of 112.10 mm, and a rear opening of 457.26 mm.

[0054] Specifically, such as Figure 1 As shown, the light source is the source of radiant energy. Its basic requirements are ease of adjustment, long working life, stable and drift-free spectral characteristics, and invariance to power supply voltage changes. Furthermore, the closer the luminescent body is to the point source, the better the focusing effect it can achieve when combined with the reflecting concentrator. Therefore, in this embodiment, a short-arc xenon lamp is selected as the light source for the radiation concentrating system. Simultaneously, to ensure that the system outlet heat flux density is not less than 1 MW / ㎡, the xenon lamp power used is 3 kW.

[0055] like Figure 2 As shown, the function of an ellipsoidal reflector is to concentrate the radiant energy of a light source in all directions to one point. In designing this device, the xenon lamp is considered a point source at the cathode spot, and an ellipsoidal mirror is chosen to concentrate the radiant energy of the light source. An ellipsoidal mirror is formed by rotating an ellipse around its major axis. An ellipse has a crucial optical property: light rays emitted from one focus of an ellipse, after reflection, converge at the other focus. Therefore, the cathode spot of the short-arc xenon lamp can be placed at the first focus of the ellipsoidal mirror. Due to the properties of an ellipsoid, light rays emitted from the cathode spot will converge at the second focus after reflection by the ellipsoidal mirror. Thus, the radiant light from the short-arc xenon lamp into the surrounding space will converge at the second focus after reflection by the ellipsoidal mirror. The ellipsoidal reflector mainly consists of a substrate and a reflective film. The substrate is made of high borosilicate glass, which can withstand temperatures up to 300–400℃. The reflective film is a total reflection aluminum film, which achieves a reflectivity of over 80% across the entire wavelength range and over 85% in most wavelength ranges. The first focal length F1 of the ellipsoidal mirror in this device is 110mm, the second focal length F2 is 495mm, the distance between the two focal points 2c 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 mirror is 77.04% according to LightTools simulation calculation.

[0056] Among them, such as Figure 3As shown, the integrator's function is to collimate and homogenize the light, ensuring one-dimensional uniformity of the outlet heat flux. The light emitted by the xenon lamp is focused at the second focal point after reflection by the ellipsoidal mirror. However, the light at this point is not uniformly collimated but rather distributed in random clusters at different angles, exhibiting extremely poor uniformity. Therefore, it cannot be directly used for heat flux calibration. The channel-reflective integrator allows the light to achieve uniform collimation after multiple reflections on the inner wall surface. The optical integrator consists of four high-reflectivity lenses, with the inner wall surface having a reflectivity of approximately 85%. Its aperture is 2cm × 2cm and its depth is 130mm. At this point, the integrator's outlet heat flux non-uniformity is less than 3%, and the outlet heat flux density is 1.6MW / ㎡. The outer surface of the integrator is covered with a water-cooled plate for cooling.

[0057] In some embodiments, such as Figure 1 As shown, the receiving system includes a high-temperature thin-film heat flow meter and a standard Gordon meter arranged sequentially along the radiation direction.

[0058] Specifically, the receiving system is used to measure and record heat flux density. The standard Gordon meter is model MEDTHERM 64, with a range of 0-1500 kW / m³. 2 The coating absorptivity is 0.92, the output voltage shows a linear relationship with the heat flux density, and the sensitivity is 0.0064 mV / (kW / m²). 2 The water cooling requirements are a water temperature of 13℃ and a flow rate of 13.5 ml / s. The uncertainty is ±3% at an expansion factor k = 2 and a confidence probability of 95%.

[0059] In some embodiments, such as Figure 1 As shown, the cooling system includes a silent centrifugal fan and a water chiller; the silent centrifugal fan is positioned in the reverse radiation direction of the short-arc xenon lamp to provide cooling for the short-arc xenon lamp; the water chiller provides cooling for the optical integrator, the standard Gordon meter, and the high-temperature thin-film heat flow meter.

[0060] Specifically, such as Figure 4 As shown and Figure 5 As shown, the cooling system includes: a 550W silent centrifugal fan for cooling the xenon lamp. Through a specially designed conical fan nozzle, the surface air velocity of the xenon lamp can reach over 13m / s, meeting the cooling requirements; two 1.749kW water-cooled units provide cooling for the optical integrator and the standard Gordon's meter (high-temperature thin-film heat flux meter), respectively; the optical integrator is cooled by four water-cooled plates, each 13cm long and 4cm wide, using an M-shaped flow channel with a diameter of 7mm. The integrator's heat flux density at maximum xenon lamp power is taken as the maximum heat flux value of 49KW / m³. 2 With an inlet water temperature of 300K and a flow rate of 0.5m / s, the average temperature of the hot surface can be controlled at 32℃, which meets the cooling requirements.

[0061] In some embodiments, such as Figure 1 The dynamic testing system is an optical chopper; the optical chopper is located at the output of the optical integrator and is used to convert the DC heat flow signal at the output of the optical integrator into a square wave heat flow signal.

[0062] Specifically, when performing frequency response testing, an optical chopper is installed at the output of the optical integrator. The function of the optical chopper is to convert the DC heat flux signal from the optical integrator output into a square wave heat flux signal, which is then input into the high-temperature thin-film heat flux meter. Its peak heat flux density is equal to the DC heat flux signal's heat flux density, and the frequency is determined by the optical chopper's chopping frequency. The model is Model300CD, and depending on the selected blade disk, it can provide chopping frequencies of 5-200Hz, 12.5-500Hz, 25-1000Hz, and 75-3000Hz, with maximum phase jumps of ±0.2°, ±0.5°, ±1°, and ±3° respectively, and long-term frequency stability of ±0.1% × maximum frequency.

[0063] In some embodiments, such as Figure 1 As shown, the support system includes an optical breadboard, guide rails, sliders, a displacement platform, an adjusting support, a clamping device, and a baffle. The optical breadboard is equipped with guide rails, sliders, a displacement platform, an adjusting support, a clamping device, and a baffle. The guide rails, sliders, displacement platform, adjusting support, clamping device, and baffle are used for the alignment and positioning of the short-arc xenon lamp, ellipsoidal reflector and optical integrator, high-temperature thin-film heat flow meter, standard Gordon meter, and optical chopper.

[0064] The data acquisition system includes a DMM7510 digital multimeter, an ADAM4018, and an ADAM4520.

[0065] The digital multimeter model is DMM7510. During static calibration, it uses DCV mode to measure DC voltage. When testing NPLC≥1, with a range of 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, it uses DigV (digital voltage) mode to measure dynamic voltage signals. With a sampling rate of 1kHz, automatic aperture, averaging 100 readings buffer, and a range of 100mV, the resolution is 1μV, and the accuracy is ±(220ppm×reading+100ppm×range).

[0066] Example 2

[0067] like Figure 6 As shown, this embodiment provides a method for integrated dynamic and static calibration of a radiation-type high-temperature thin-film heat flux meter, including:

[0068] Turn on the xenon lamp power to make it light up.

[0069] The light emitted by the xenon lamp is reflected by an ellipsoidal mirror and focused at the entrance of the optical integrator.

[0070] After multiple reflections inside the optical integrator, light is collimated and output in a uniform manner.

[0071] 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 the high-temperature thin-film heat flow meter with input heat flow of different heat flow densities.

[0072] During the dynamic calibration process, collimated and uniform light is input into an optical chopper, and the DC heat flow signal is converted into a square wave heat flow signal based on the optical chopper, which is then input into a high-temperature thin-film heat flow meter for dynamic heat flow calibration.

[0073] The formula for calculating the heat flux density is as follows:

[0074] q = C·E s

[0075] Where q is the heat flux density, C is the probe coefficient of the thin-film heat flux meter, and E S The output thermoelectric potential of the thin-film heat flow meter is determined. The specific formula for calculating the probe coefficient of the thin-film heat flow meter is as follows:

[0076]

[0077] Where λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 represent thermal resistance layers made 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 jointly determined by the thermal conductivity, thickness, number of thermopile nodes, and Seebeck coefficient of the thin-film heat flux meter's thermal resistance layer, reflecting that when the heat flux meter outputs a potential of 1V, a heat flux with a heat flux density of C (W / ㎡) passes perpendicularly through the thin-film heat flux meter.

[0078] That is, we get the formula

[0079] The derivation of this formula is as follows:

[0080] First, in this embodiment, the heat flow meter calibration device has the following advantages:

[0081] ① High heat flux density: By focusing light through an ellipsoidal mirror, a heat flux density of 1.64 W / m² can be generated at a heat flux meter with a size of 2cm×2cm.

[0082] That is, the formula for calculating heat flux density is:

[0083] In the formula, η1 is the photoelectric conversion efficiency of the xenon lamp (approximately 45%), η2 is the energy utilization rate of the ellipsoidal mirror (approximately 80%), and η3 is the energy utilization rate of the integrator (approximately 40%–50%).

[0084] ② Good uniformity: By controlling the focal length of the ellipsoidal mirror and the depth of the integrator, the non-uniformity of the heat flux density at the integrator outlet can be controlled within 3%, specifically as follows: Figure 7 As shown.

[0085] ③ Integrated static and dynamic calibration: This calibration device can convert static heat flux into dynamic heat flux by adding a chopper, thereby calibrating the dynamic characteristics of the thin-film heat flux meter, such as... Figure 8 , Figure 9 These are the static and dynamic characteristics of the thin-film heat flow meter calibrated on this device, respectively.

[0086] Therefore, the basic principle of thin-film heat flow meter measurement is one-dimensional Fourier's law. When heat flows through the surface of the heat flow meter, a temperature difference will be generated between the upper and lower surfaces of the thermal resistance layer due to heat transfer. Figure 10 As shown, by measuring this temperature difference in a certain way, the magnitude of the heat flux can be calculated using the one-dimensional Fourier law. The formula for calculating the heat flux is:

[0087]

[0088] In the formula, q is the heat flow 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 temperatures of the upper and lower surfaces of the thermal resistance layer, respectively.

[0089] As can be seen from the heat flux calculation formula, the key to the measurement of the thermal resistance layer lies in the measurement of the temperature difference. First, to ensure a sufficiently large temperature difference when heat flux passes through, the thermal resistance layer is usually made of materials with stable physical properties and high thermal resistance, such as silicon dioxide and polyimide. Second, it is also necessary to ensure the accuracy of the temperature difference measurement. Common methods include arranging thermistor 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 on the micrometer scale, even if a large heat flux passes through the thermal resistance layer, the temperature difference between its upper and lower surfaces is very small, resulting in a very small output signal from the thin-film thermocouple, which is not conducive to signal acquisition. Therefore, a series of thin-film thermocouples are usually connected in series at a location where the temperature of the thermal resistance layer is uniform to amplify the signal and reduce noise interference. The structure formed by a series of thermocouples connected in series is called a thermopile. Early thermopile-type thin-film heat flow meters could measure relatively low thermal parameters. Their common structure used the upper and lower surfaces of a thermal resistance layer as the hot and cold endpoints, with a thermopile (also called a sensing layer) arranged on top. This measurement model perfectly matched the principles of heat flow measurement. However, this structure introduced the drawback of the sensing layer film spanning the thermal resistance layer. Whether using a method of directly winding wires around the edge of the thermal resistance layer or using hydrofluoric acid to etch the thermal resistance layer to connect the nodes above and below, problems such as sensing layer breakage or failure at high temperatures were unavoidable. Furthermore, improper control of the hydrofluoric acid dosage could cause additional corrosion to the substrate material.

[0090] To address the structural instability issue caused by thermopile-type thin-film heat flow meters crossing thermal resistance layers, this application proposes a series of structures with sensitive layers deposited on the same horizontal plane by introducing reasonable assumptions. The most typical examples are thin-film heat flow meters with multiple thermal resistance materials of single thickness and thin-film heat flow meters with a single thermal resistance material of multiple thicknesses, such as... Figure 11 and Figure 12 As shown.

[0091] This type of thin-film heat flow meter introduces two reasonable assumptions: first, the heat flow through different thermal resistance layers of the same heat flow meter is one-dimensional and equal; second, the surface temperature of different thermal resistance layers is equal. Substituting these assumptions into the heat flow calculation formulas for different thermal resistance layers yields the formula for calculating the heat flow of the heat flow meter. Taking a heat flow meter designed by our research team with different thermal resistance layer materials of the same thickness as an example, we derive its heat flow calculation formula. For thermal resistance layers of the same thickness but different materials, since the magnitude of the heat flow is equal, the formula can be obtained from one-dimensional Fourier's law as follows:

[0092]

[0093] Assuming the upper surface temperature of the thermal resistance layer is the same, a temperature difference will appear on the lower surface of thermal resistance layers made of different materials. The formula for calculating the temperature difference is:

[0094] ΔT=ΔT1-T2

[0095] For thermopile-type thin-film heat flow meters, the temperature difference is measured by the thermoelectric potential generated at the thermopile nodes. For a thermopile with N nodes, the relationship between its thermoelectric potential output and the temperature difference is as follows:

[0096] E s =N×S(T)×ΔT

[0097] In the formula: S(T) is the Seebeck coefficient of the material.

[0098] By combining the above equations, we can obtain the relationship between the heat flux and the output thermoelectric potential:

[0099]

[0100] The ratio of heat flux to output thermoelectric potential of a thermopile-type thin-film heat flow meter is a relationship composed of the thermal conductivity and thickness of the thermal resistance layer and the number of thermopile nodes, and is called the probe coefficient.

[0101] One of the main purposes of heat flux calibration is to obtain the probe coefficient or sensitivity of the heat flux meter when the heat flux and output thermoelectric potential are known.

[0102] In summary, this application has the following technical effects:

[0103] This application proposes an integrated dynamic and static calibration device and method for a radiation-type high-temperature thin-film heat flow meter, which can provide 0.3 MW / m 2 -1.6MW / m 2 With an input heat flux density non-uniformity of <3% and a static calibration relative standard uncertainty of <3.10%, it can meet the frequency response calibration requirements of thin-film heat flux meters with a cutoff frequency >1500Hz. This solves the problem that current thin-film heat flux meter calibration devices 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 in engines, gas turbines, and other applications.

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0105] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A radiation type high-temperature thin-film heat flow meter dynamic-static integrated calibration device, characterized in that, The integrated dynamic and static calibration device for a radiation-induced high-temperature thin-film heat flux meter includes: The system comprises a radiation system, a receiving system, a support system, a cooling system, a dynamic testing system, and a data acquisition system. The radiation system provides a stable source of radiant energy and regulates and focuses the radiant energy. The receiving system measures and records heat flux density. Adjacent radiation and receiving systems are mounted on the support system. The cooling system provides cooling to the radiation and receiving systems using water or air cooling. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The dynamic testing system, located at the outlet of the radiation system, converts the DC heat flux signal output by the radiation system into a square wave heat flux signal. The data acquisition system collects and processes data from the radiation, receiving, cooling, and dynamic testing systems. The radiation system includes a short-arc xenon lamp, an ellipsoidal reflector, and an optical integrator arranged sequentially along the radiation direction; the short-arc xenon lamp has a power of 3KW; the ellipsoidal reflector consists of a substrate and a reflective film; the substrate is made of 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 focal distance of 385mm, a front opening of 112.10mm, and a rear opening of 457.26mm. The function of the integrator is to collimate and uniformly reflect light, ensuring one-dimensional uniformity of the outlet heat flow. The channel-reflective integrator allows light to achieve uniform collimation after multiple reflections on the inner wall surface. The optical integrator consists of four high-reflectivity lenses, with the inner wall surface having a reflectivity of about 85%. Its aperture is 2cm×2cm and its depth is 130mm. At this point, the non-uniformity of the outlet heat flow of the integrator is less than 3%, and the outlet heat flow density is 1.6MW / ㎡. The outer surface of the integrator is wrapped with a water-cooling plate for cooling. The receiving system includes a high-temperature thin-film heat flow meter and a standard Gordon meter arranged sequentially along the radiation direction; The dynamic testing system is an optical chopper; the optical chopper is located 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. The support system includes an optical breadboard, guide rails, sliders, a displacement platform, an adjusting support, a clamping device, and a baffle. The optical breadboard is equipped with guide rails, sliders, a displacement platform, an adjusting support, a clamping device, and a baffle. The guide rails, sliders, displacement platform, adjusting support, clamping device, and baffle are used for the alignment and positioning of short-arc xenon lamps, ellipsoidal reflectors and optical integrators, high-temperature thin-film heat flow meters, standard Gordon gauges, and optical choppers. The cooling system includes a silent centrifugal fan and a water chiller; the silent centrifugal fan is positioned in the reverse radiation direction of the short-arc xenon lamp to provide cooling for the short-arc xenon lamp; the water chiller provides cooling for the optical integrator, the standard Gordon meter, and the high-temperature thin-film heat flow meter.

2. The dynamic and static integrated calibration device for a radiation type high-temperature thin-film heat flow meter according to claim 1, characterized in that, The data acquisition system includes a DMM7510 digital multimeter, an ADAM4018, and an ADAM4520.

3. A calibration method based on the static and dynamic integrated calibration device of a radiation type high-temperature thin-film heat flow meter according to any one of claims 1-2, characterized in that, include: Turn on the xenon lamp power to make it light up; The light emitted by the xenon lamp is reflected by an ellipsoidal mirror and focused at the entrance of the optical integrator. After multiple reflections inside the optical integrator, light is collimated and output in a uniform manner. 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 the high-temperature thin-film heat flow meter with input heat flow of different heat flux densities; During the dynamic calibration process, collimated and uniform light is input into an optical chopper, and the DC heat flow signal is converted into a square wave heat flow signal based on the optical chopper, which is then input into a high-temperature thin-film heat flow meter for dynamic heat flow calibration.

4. The calibration method of claim 3, wherein The formula for calculating the heat flux density is: ； where q is the heat flux, C is the film calorimeter probe constant, E S is the output thermoelectric potential of the film calorimeter.

5. The calibration method of claim 4, wherein, The specific formula for calculating the probe coefficient of the thin-film heat flow meter is as follows: ； Where λ is the thermal conductivity of the thermal resistance layer, subscripts 1 and 2 represent thermal resistance layers made 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.

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