Water-free high-temperature heat flux-temperature synchronous measurement sensor and preparation method thereof

Abstract

The present invention belongs to the field of high-temperature sensing technology, and specifically relates to a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor and its preparation method. The sensor includes a functional layer, a thermal resistance layer, and a protective layer arranged in sequence; the functional layer is arranged on the surface of the substrate by screen printing, and includes two thermocouple lead electrodes, two heat flow lead electrodes, multiple positive sensitive electrodes, and multiple negative sensitive electrodes. The positive sensitive electrodes and the negative sensitive electrodes are spaced apart and connected along multiple parallel straight lines to form thermocouple pairs. The electrodes at the head or end of each parallel straight line are symmetrically inclined and extended to connect with the electrodes on the adjacent parallel straight lines to form an S-shaped curve-arranged thermocouple pair; the thermal resistance layer is used to cover the cold junction of the functional layer, and a plurality of node seams are provided on the thermal resistance layer. The position of the node seams corresponds to the position of the hot junction of the thermocouple pair, and is used to expose the hot junction. The present invention is simple to prepare, has high sensitivity, and is suitable for high-temperature and highly variable thermal flow field environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature sensing, and in particular relates to a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor and a preparation method thereof. Background Art

[0002] High-temperature components in the aviation, aerospace, automotive and other industrial fields, especially high-temperature rotating components such as engine blades and turbine disks, are prone to thermal fatigue and thermal damage, which can lead to fission, due to the continuous erosion of high-temperature airflow on the surface. Therefore, accurately measuring their surface temperature and heat flux density is of great significance for their reliability and safety research. At present, common temperature measurements include non-contact temperature measurement technologies such as ultrasound, fluorescence, infrared radiation, and radio frequency, and contact temperature measurement technologies such as irradiated crystals, temperature-indicating paints, thin-film thermocouples, and platinum resistance thermometers. Common heat flux measurements, that is, heat flux density tests, use sensors such as Gordon meters, thermopile sensors, coaxial thermocouple heat flux meters, and Schmidt-Boelter heat flux meters. Most existing heat flux density test products require water cooling, their structures are relatively complex, and their measurement accuracy is limited.

[0003] With the advancement of micron-nanotechnology (MEMS) technology and high-performance heat-resistant and heat-insulating materials, thin-film thermocouples and heat flux sensors offer significant advantages for real-time, continuous, and high-in-situ measurement of high-temperature parameters, thanks to their compact size, high-temperature resistance, superior performance, and minimal impact on the field environment. Existing technologies include sensors that integrate thermopiles and thermocouples for simultaneous heat flux and temperature measurement, but these techniques are complex and difficult to fabricate directly on high-temperature component surfaces, making them unsuitable for in-situ measurement.

[0004] Therefore, it is necessary to invent a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor and its preparation method to realize in-situ measurement of heat flux and temperature data in a real-time high-temperature environment and improve measurement accuracy. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor and a preparation method thereof. By improving the sensor structure and simplifying the preparation process, the in-situ preparation and in-situ measurement of the sensor can be realized, thereby improving the measurement accuracy.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a water-free high-temperature heat flux-temperature synchronous measurement sensor, comprising a functional layer, a thermal resistance layer and a protective layer arranged in sequence;

[0007] The functional layer is provided on the surface of the substrate by screen printing, and includes a first thermocouple lead electrode, a second thermocouple lead electrode, a first heat flow lead electrode, a second heat flow lead electrode, a plurality of positive sensitive electrodes, and a plurality of negative sensitive electrodes. The positive sensitive electrodes and the negative sensitive electrodes are spaced apart and connected along a plurality of parallel straight lines to form a plurality of sequentially connected thermocouple pairs. The electrodes at the head end or the tail end of each parallel straight line are symmetrically inclined and extended to connect with the electrodes on the adjacent parallel straight line to form an S-shaped curve arrangement. The diameter of the connection point of the end of the positive sensitive electrode and the negative sensitive electrode is greater than the electrode width.

[0008] The first thermocouple lead electrode and the second thermocouple lead electrode are respectively connected to the positive sensitive electrode and the negative sensitive electrode of one of the thermocouple pairs; the first heat flow lead electrode is connected to the positive sensitive electrode at the beginning of the S-shaped curve, and the second heat flow lead electrode is connected to the negative sensitive electrode at the end of the S-shaped curve;

[0009] The thermal resistance layer is used to cover the functional layer, and a plurality of node seams perpendicular to the straight line direction of the positive sensitive electrode and the negative sensitive electrode are provided on the thermal resistance layer. The positions of the node seams correspond to the positions of the hot nodes of the thermocouple pair, and are used to expose the hot nodes.

[0010] The water-free, high-temperature-resistant heat flux-temperature synchronous measurement sensor further includes an insulating layer, which is arranged between the substrate and the functional layer.

[0011] In the functional layer, the first thermocouple lead electrode, the first heat flow lead electrode, and the positive sensitive electrode are made of Pt-Rh10, and the second thermocouple lead electrode, the second heat flow lead electrode, and the negative sensitive electrode are made of Pt.

[0012] The protective layer is made of aluminum oxide slurry through screen printing, and the thermal resistance layer is made of nano-composite ceramic material.

[0013] Electrode gaps for exposing the lead electrodes are provided at positions on the thermal resistance layer corresponding to the first thermocouple lead electrode, the second thermocouple lead electrode, the first heat flow lead electrode, and the second heat flow lead electrode.

[0014] The diameter Φ of the connection point of the ends of the positive sensitive electrode and the negative sensitive electrode is 1.5b~2b, and the electrode spacing on two adjacent parallel straight lines is 2Φ~4Φ, where b represents the width of the positive sensitive electrode and the negative sensitive electrode, and the length of the positive sensitive electrode and the negative sensitive electrode is 4b~10b.

[0015] The present invention also provides a method for preparing a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor, which comprises the following steps:

[0016] Step 1: Clean the substrate surface;

[0017] Step 2: Fix the screen printing mask of the positive sensitive electrode on the surface of the substrate, evenly apply the positive sensitive electrode slurry, and use a scraper to push back and forth at a uniform speed according to the pattern to obtain the positive sensitive electrode with a connection point at the end, the first thermocouple lead electrode and the first heat flow lead electrode, and then dry and cool naturally;

[0018] Step 3: After aligning the screen printing mask of the negative sensitive electrode with the substrate, fix it on the surface of the substrate, evenly apply the negative sensitive electrode slurry, and use a scraper to push back and forth at a uniform speed according to the pattern to obtain a negative sensitive electrode whose end connection point coincides with the end connection point of the positive sensitive electrode, a second thermocouple lead electrode, and a second heat flow lead electrode, and then dry it. After natural cooling, the functional layer is obtained;

[0019] Step 4: sintering the functional layer at high temperature;

[0020] Step 5: Place the thermal resistance layer mask above the functional layer, align it, and spray the thermal resistance material with a spray gun. After spraying, place it in the air to dry to obtain the thermal resistance layer.

[0021] Step 6: Place the protective layer mask just above the thermal resistance layer, align it and evenly apply the protective layer slurry, use a scraper to push it back and forth at a constant speed according to the pattern, and then dry it;

[0022] Step 7: Use high-temperature conductive glue to fix each electrode wire at the position of the first thermocouple lead electrode, the second thermocouple lead electrode, the first heat flow lead electrode, and the second heat flow lead electrode, then solidify and sinter them, and take them out after cooling to complete the preparation of the heat flow sensor.

[0023] The step 1 further comprises the following steps:

[0024] After the substrate surface is cleaned, a high-temperature resistant insulating medium slurry is evenly applied on the substrate surface through an insulating layer mask, and then dried, naturally cooled, and then sintered at a high temperature to obtain an insulating layer.

[0025] The method for preparing a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor further includes the step of setting a calibration mark on the surface of the substrate.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The invention proposes a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor and a preparation method thereof. By directly preparing a functional layer, a thermal resistance layer, and a protective layer on a base layer, wherein the functional layer includes a plurality of regularly arranged thermocouple pairs, not only can the synchronous measurement of heat flux and temperature be achieved, but also, through the reasonable design of the thermocouple arrangement, under the premise of the same process, the output of the logarithm and thermoelectric potential of the thermocouple can be greatly improved, which can improve the sensitivity of the sensor. Moreover, for a continuous heat flow environment, the sensor of the present invention has a higher response speed and heat output, and the water-free design is conducive to in-situ testing.

[0028] 2. In the present invention, the sensor is prepared by screen printing. Compared with the sputtering process, it has better temperature resistance and a simple preparation process, which is conducive to the in-situ preparation and testing of the sensor. In addition, it can also be used as an industrial non-in-situ test sensor. It can be prepared on a thin ceramic substrate or a water-cooled ceramic cavity surface, and has a high response time and temperature resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor provided in Example 1 of the present invention;

[0030] Figure 2 Schematic top view of the functional layer in Example 1 of the present invention;

[0031] Figure 3 This is a schematic top view of a thermal resistance layer covering the functional layer in Example 1 of the present invention;

[0032] Figure 4 A schematic diagram of circuit connections for testing the sensor according to the first embodiment of the present invention;

[0033] Figure 5 Schematic diagram of the electrode arrangement in the sensor;

[0034] Figure 6 A process flow chart of a sensor preparation method provided in Example 2 of the present invention, wherein (a) represents a substrate cleaning process, (b) represents an insulating layer preparation process, (c) represents an insulating layer drying process, (d) represents a functional layer positive sensitive electrode preparation process, (e) represents a functional layer negative sensitive electrode preparation process, (f) represents a functional layer sintering process, (g) represents a thermal resistance layer preparation process, (h) represents a protective layer preparation process, and (j) represents a lead preparation process;

[0035] Figure 7 Schematic diagram showing the comparison of heat flux test sensitivity between the sensor of the present invention and a standard Gordon meter;

[0036] Figure 8Schematic diagram comparing the linear fitting curves of the output voltage VS heat flux of the sensor of the present invention and the Gordon meter;

[0037] Figure 9 Schematic diagram of the heat flux test output voltage and corresponding thermocouple temperature of the sensor of the present invention and the Gordon meter under the same test conditions.

[0038] In the figure: 1 is the substrate, 2 is the insulating layer, 3 is the functional layer, 4 is the thermal resistance layer, 5 is the protective layer, 7 is the positive sensitive electrode, 8 is the negative sensitive electrode, 9 is the hot junction, 10 is the cold junction, 11 is the first thermocouple lead electrode, 12 is the second thermocouple lead electrode, 13 is the second heat flow lead electrode, 14 is the first heat flow lead electrode, 15 is the calibration mark, and 16 is the node seam. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figures 1-3 As shown, an embodiment of the present invention provides a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor, comprising a functional layer 3, a thermal resistance layer 4 and a protective layer 5 arranged in sequence.

[0042] Among them, the functional layer 3 is arranged on the surface of the substrate 1 by screen printing, and includes a first thermocouple lead electrode 11, a second thermocouple lead electrode 12, a second heat flow lead electrode 13, a first heat flow lead electrode 14, a plurality of positive sensitive electrodes 7 and a plurality of negative sensitive electrodes 8. The positive sensitive electrodes 7 and the negative sensitive electrodes 8 are connected at intervals along multiple parallel straight lines to form a plurality of thermocouple pairs, and the electrodes located at the head end or the end of each parallel straight line are symmetrically inclined and extended to connect with the electrodes on the adjacent parallel straight lines to form an S-shaped curve arrangement of thermocouple pairs; the connection points at the ends of the positive sensitive electrode 7 and the negative sensitive electrode 8 coincide to form a hot node 9 or a cold node 10; the diameter of the connection point is greater than the electrode width.

[0043] Specifically, the first thermocouple lead electrode 11 and the second thermocouple lead electrode 12 are respectively connected to the positive sensitive electrode 7 and the negative sensitive electrode 8 of one of the thermocouple pairs; the first heat flow lead electrode 14 is connected to the positive sensitive electrode 7 at the head end of the S-shaped curve, and the second heat flow lead electrode 13 is connected to the negative sensitive electrode 8 at the end end of the S-shaped curve.

[0044] Specifically, the thermal resistance layer 4 is used to cover the functional layer 3, and a plurality of node seams 16 are provided on the thermal resistance layer 4, which are perpendicular to the straight lines where the positive sensitive electrodes 7 and the negative sensitive electrodes 8 are located. The positions of the node seams 16 correspond to the positions of the hot junctions 9 of each thermocouple pair, and are used to expose the hot junctions 9. Specifically, in this embodiment, except for the electrodes at the head and tail ends, the number of positive sensitive electrodes 7 and negative sensitive electrodes 8 on each parallel straight line is equal. Therefore, the positions of the hot junctions 9 on each straight line correspond, which facilitates the provision of the node seams 16.

[0045] Furthermore, in this embodiment, when the substrate 1 is a conductor, the sensor further includes an insulating layer 2 , and the insulating layer 2 is disposed between the substrate 1 and the functional layer 3 .

[0046] Furthermore, the sensor of this embodiment can not only be directly prepared on the surface of the object to be measured, in which case the surface of the object to be measured is the base 1 of the sensor; in addition, the sensor can also include a base 1 made of insulating material and a shell, and the functional layer 3, the thermal resistance layer 4 and the protective layer 5 are arranged on the base 1, and then the entire sensor is packaged by the shell. Moreover, a snap mechanism can also be provided on the shell to fix the sensor at the position to be measured.

[0047] Specifically, in this embodiment, in the functional layer 3, the material of the first thermocouple lead electrode 11, the first heat flow lead electrode 14, and the positive sensitive electrode 7 is Pt-Rh10, and the material of the second thermocouple lead electrode 12, the second heat flow lead electrode 13, and the negative sensitive electrode 8 is Pt. Figure 2 As shown, the negative sensitive electrode 8 and the corresponding lead electrode are represented by hatching. Furthermore, in this embodiment, there can be two pairs of first thermocouple lead electrodes 11 and second thermocouple lead electrodes 12. By measuring the temperature at different locations through the two pairs of lead electrodes, it is possible to detect whether the temperature at the measurement location is uniform, and then preliminarily determine the stability of the sensor's heat flow environment.

[0048] Specifically, in this embodiment, the protective layer 5 is made of alumina slurry or silicon dioxide slurry through screen printing, and the thermal resistance layer 4 is made of nano-composite ceramic material.

[0049] Specifically, in this embodiment, electrode gaps are provided on the thermal resistance layer 4 at positions corresponding to the first thermocouple lead electrode 11 , the second thermocouple lead electrode 12 , the first heat flow lead electrode 14 , and the second heat flow lead electrode 13 to expose these lead electrodes.

[0050] like Figure 4As shown in FIG. 1 , a circuit connection diagram of the sensor of this embodiment is shown, in which the heat flux density signal output by the first heat flow lead electrode 14 and the second heat flow lead electrode 13 and the temperature signal output by the first thermocouple lead electrode 11 and the second thermocouple lead electrode 12 are amplified and filtered by the amplifier, analog-to-digital converted by the ADC converter, and then input into the FPGA for framing, encoding, storage and forwarding, and then transmitted to the computer for data processing. In addition, the ADC converter is also connected to a platinum resistor R to correct the temperature signal.

[0051] Specifically, in this embodiment, the diameter Φ of the connection point is 1.5b~2b, and the electrode spacing on two adjacent parallel straight lines is 2Φ~4Φ, where b represents the width of the positive sensitive electrode 7 and the negative sensitive electrode 8, and the length of the positive sensitive electrode 7 and the negative sensitive electrode 8 is 4b~10b.

[0052] In a limited space, under the premise of a fixed process, designing as many thermocouple pairs as possible can improve sensitivity and heat output. Specifically, the expression of sensitivity is:

[0053] ; (1)

[0054] in, S k is the sensitivity of the heat flow sensor, μv / (W / ㎡); E is the thermoelectric potential output by the thermopile composed of the thermocouple array, μv; q is the vertical heat flux density; N is the number of thermocouples; S T is the Seebeck coefficient of the thermocouple (µV / °C or V / K); ΔT is the temperature gradient difference between the two surfaces of the thermal resistance layer 4; is the thermal conductivity of the thermal resistance layer 4; is the thickness of the thermal resistance layer 4, therefore, the sensitivity S k and the temperature gradient difference Δ T It does not matter, depending on the thickness of the thermal resistance layer 4 The sensitivity of the sensor can be obtained. The reason for the change in sensitivity is the Seebeck coefficient S T The sensitivity of the sensor will vary due to changes in ambient temperature, but transient test temperatures will not cause significant fluctuations in sensitivity, allowing for accurate measurement of transient heat flux changes. The greater the number of thermocouple pairs N within the same area, the greater the sensor sensitivity. Therefore, the embodiments of the present invention optimize sensitivity through rational design by optimizing the number of thermocouple pairs N within the same area, making them suitable for high-temperature and highly variable thermal flow field environments. The following describes the electrode design optimization principles of the present invention.

[0055] N thermocouples form a thermopile group, and each thermocouple contains two sensitive electrodes made of different materials, namely a positive sensitive electrode 7 and a negative sensitive electrode 8. The positive sensitive electrode 7 and the negative sensitive electrode 8 are designed with the same size. Figure 5 As shown, it is assumed that the length of each sensitive electrode is a, the width is b, and the angle is θ. l is the horizontal projection of the electrode, h is the sum of the vertical projections of the electrodes, and d is the horizontal spacing of the thermocouples. The connection point of the positive sensitive electrode 7 and the negative sensitive electrode 8 is a diameter of Φ. Then:

[0056] ; (2)

[0057] If the length a of the sensitive electrode is very short, the cold junction 10 and the hot junction 9 will quickly reach thermal equilibrium, and the transverse thermoelectric effect of the thermocouple will be obvious, so the heat flux density test cannot be used. In order to place as many thermocouple pairs as possible within a limited size, the electrode length a should not be too large, otherwise the reliability will be reduced. The number of pairs of sensors is calculated based on the number n of hot junctions 9, which can be combined with the sensor area X*Y (X Y) and the already determined thermode size are calculated.

[0058] X is the length, Y is the width, is the number of horizontal hot nodes 9, is the number of vertical thermal nodes 9. Can only take positive integers. Then:

[0059] ; (3)

[0060] Therefore, the number of thermocouple pairs N that can be included in the X*Y dimension is:

[0061] ; (4)

[0062] Comprehensively consider the structure of the heat flow sensor, according to the limit size of the screen printing process and the requirements of the electrode paste, the width of the sensitive electrode b The value should be at least greater than 0.2mm, and the edge blank distance should be b Assuming the sensitive electrode length a Take 4 b ~10 b , sensitive node diameter Φ Take 1.5 b ~2 b , horizontal spacing between node centers d Take 2 Φ ~4 Φ , vertical spacing between nodes of the same type h Take 3 Φ ~2 a , lead electrode side length c 3 b~6b, the width can be adjusted appropriately according to actual lead requirements. h and l The value and angle of The limit value is Then the positive sensitive electrode 7 and the negative sensitive electrode 8 are located on the same straight line, assuming that: X = Y =20mm, b =0.3mm, a =6 b =1.8mm, Φ =2 b ≈0.6mm, the limit value is , h =2 a =12 b , l =0, d= 2.33 Φ ≈1.4mm, lead electrode side length c 4 b , top and bottom margins are b , with left and right margins of Φ . Then we have:

[0063] ; (5)

[0064] Therefore, the present invention can be used in 20×20mm 2 Finally, the length and width of the electrode lead are related to the lead diameter. The external lead diameter is less than 0.2 mm. If it is too thick, the electrode on the sensor substrate 1 may be easily pulled off due to stress.

[0065] Example 2

[0066] like Figure 6 As shown, the second embodiment of the present invention provides a method for preparing a water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor, which is used for the water-free, high-temperature resistant heat flux-temperature synchronous measurement sensor described in the first embodiment. The method is prepared by a screen printing process, which greatly reduces the difficulty of preparation and has good temperature resistance. The method specifically includes the following steps:

[0067] Step 1: Clean the surface of substrate 1 and treat substrate 1.

[0068] In this embodiment, the substrate 1 is cleaned with plasma water and anhydrous alcohol using an ultrasonic cleaning machine and then wiped dry with dust-free paper.

[0069] In this embodiment, the substrate 1 is treated as follows: the substrate 1 is dried in a 120°C insulated oven for 15-30 minutes, cooled naturally, and then placed in a muffle furnace for high-temperature sintering at a rate of 5°C / min, with the peak temperature maintained for at least 20 minutes. Depending on the heat resistance of the substrate 1, the peak temperature is limited to the lower temperature limit of the substrate 1 or the slurry of the insulating layer 2, and is generally set at or above 850°C.

[0070] Step 2: Fix the screen printing mask of the positive sensitive electrode 7 on the surface of the substrate 1, evenly apply the positive sensitive electrode 7 slurry, and use a scraper to push back and forth at a uniform speed according to the pattern to obtain the positive sensitive electrode 7 with a connection point at the end, as well as the first thermocouple lead electrode 11 and the first heat flow lead electrode 14, and then dry and cool naturally.

[0071] In step 2 of this embodiment, the product is placed in a 120° C. heat preservation box and dried for 15 to 30 minutes, then taken out and allowed to cool naturally.

[0072] Step 3: After aligning the screen printing mask of the negative sensitive electrode 8 with the substrate 1, fix it on the surface of the substrate 1, evenly apply the negative sensitive electrode 8 slurry, and use a scraper to push back and forth at a uniform speed according to the pattern to obtain the negative sensitive electrode 8 whose end connection point coincides with the end connection point of the positive sensitive electrode 7, as well as the second thermocouple lead electrode 12 and the second heat flow lead electrode 13, and then dry and cool naturally to obtain the functional layer 3.

[0073] Similarly, in step 3, after screen printing, place the film in a 120°C heat preservation box and dry it for 15 to 30 minutes, then take it out and wait for it to cool naturally to evaporate the solvent.

[0074] In this embodiment, the printing pastes of the positive sensitive electrode 7 and the negative sensitive electrode 8 are Pt-Rh10 and Pt, such as ESL 5541-S and ESL 5541-A respectively; a printing mask with 200-325 mesh, 30N tension and 20um film thickness is selected for screen printing.

[0075] Step 4: sintering the functional layer 3 at high temperature.

[0076] In this embodiment, after the functional layer 3 is prepared, the device is placed in a muffle furnace for high-temperature sintering. The temperature is maintained for 30 minutes, and then removed after natural cooling. This allows the organic solvent in the slurry to completely evaporate, removes surface impurities, and firmly adheres the metal sensitive electrode to the surface of the insulating substrate. The sintering temperature is set based on the sintering temperature requirements of the sensitive electrode slurry. Generally, the sensitive electrode material is selected with a temperature resistance close to that of the substrate 1. In this embodiment, the high-temperature sintering temperature is 1350°C, and the sintering time is 30 minutes.

[0077] Step 5: Place the thermal resistance layer mask above the functional layer 3, align and spray the thermal resistance material using a spray gun. After spraying, place it in the air for 24 hours to dry to obtain the thermal resistance layer 4.

[0078] Specifically, in step 5, use an air spray gun with a diameter of 0.8 mm and a pressure of 0.6 MPa to evenly spray the thermal resistance material perpendicular to the front of the mask. After spraying, let it dry in air for 24 hours. The thermal resistance layer 4 needs to be made of a material with a higher temperature resistance than the functional layer 3 and the insulating layer 2.

[0079] Specifically, the thermal resistance layer 4 is made of nano-composite ceramic material. When preparing the thermal resistance layer 4, a mask with a screen size of 200-250 mesh, a film thickness of 20 μm, and a tension of 30 N is used. An air spray gun with a diameter of 0.8 mm and a pressure of 0.6 MPa is used, and the layer is naturally dried for 24 hours.

[0080] Step 6: Place the protective layer mask just above the thermal resistance layer 4, align it and evenly apply the protective layer slurry, use a scraper to push it back and forth at a uniform speed according to the pattern, and then dry and sinter at high temperature.

[0081] Specifically, in step 6, the product is placed in a 120° C. heat preservation box and dried for 15 to 30 minutes to evaporate the solvent.

[0082] Specifically, the protective layer 5 is made of alumina or other slurries with high thermal conductivity and high temperature resistance. The protective layer 5 is prepared using a mask with a screen size of 200-250 mesh, a film thickness of 5 μm, a tension of 30 N, and a high-temperature sintering temperature of 1000°C / 30min.

[0083] In addition, in this embodiment, the thermal resistance layer mask and the protection layer mask can also be prepared using a flexible polyimide film.

[0084] Step 7: Use high-temperature conductive glue to fix each electrode wire at the positions of the first thermocouple lead electrode 11, the second thermocouple lead electrode 12, the first heat flow lead electrode 14, and the second heat flow lead electrode 13, then solidify and sinter them, and take them out after cooling to complete the preparation of the heat flow sensor.

[0085] In step 7, a 0.1 mm diameter electrode wire is secured to the electrode position using a high-temperature conductive paste. This wire is used to transmit the sensor's output thermoelectric potential to a high-precision data acquisition device. After securing, the wire is placed in a muffle furnace and sintered and cured for 0.5 hours. After cooling, the wire is removed, completing the heat flow sensor fabrication. The first heat flow lead electrode 14 and the first thermocouple lead electrode 11 are made of the same material as the positive sensitive electrode 7; the second heat flow lead electrode 13 and the second thermocouple lead electrode 12 are made of the same material as the negative sensitive electrode 8.

[0086] Furthermore, in this embodiment, when the substrate 1 is a conductor, the step 1 further includes the following steps:

[0087] After the surface of the substrate 1 is cleaned, a high-temperature resistant insulating medium slurry is evenly applied on the surface of the substrate 1 through an insulating layer mask using a screen printing process, and then dried, naturally cooled, and then sintered at a high temperature to obtain an insulating layer 2.

[0088] Furthermore, the method for fabricating a water-free, high-temperature heat flux-temperature synchronous measurement sensor according to this embodiment further includes the step of providing a calibration mark 15 on the surface of substrate 1. Providing calibration mark 15 allows alignment of the various masks, improving fabrication process accuracy. Calibration mark 15 can be provided on the screen-printed mask of positive sensitive electrode 7.

[0089] To test the repeatability and stability of the sensor provided by this invention, a heat flux sensor testing system was constructed. It consists of a muffle furnace (KSL1800X-A1, China), a ceramic-encapsulated S-type standard thermocouple, a water-cooled Gordon meter (GD-B5-5M, China), a high-precision weak signal acquisition device (DAQ), mullite bricks, and a test computer. The muffle furnace provides a radiant heat source via a heating resistor. The heat flux density of the radiation source and the ambient temperature are calibrated using a standard Gordon meter and S-type thermocouple. The heat flux sensor and Gordon meter to be tested are fixed to the center of the muffle furnace mouth via mullite, with the sensitive surfaces aligned vertically to expose them to the same radiant heat flux environment. The S-type standard thermocouple is fixed to the center of the mullite brick to provide the accurate operating ambient temperature of the heat flux sensor. The data acquisition device, in conjunction with the test computer, synchronizes the thermoelectric potential signals output by the S-type thermocouple, Gordon meter, and HTHFS. The performance of the heat flux sensor is evaluated through comparison. The upper temperature limit for the heat flux sensor test is set to 1400°C.

[0090] The average sensitivity of the standard Gordon meter is 2.45μV / (kW / m 2 ), the measurable upper limit is 5MW / m 2 The heat flux density is 20-25°C. Cold water at 3 L / min is circulated through the back end of the probe via a water cooling device to ensure stable output from the heat flow meter. The Gordon meter has advantages such as good linearity and high stability, making it a suitable reference device for HTHFS calibration. The muffle furnace has a heating rate of 5°C / min and 10°C / min at (50-400)°C and (400-1400)°C, respectively, and is maintained at 400°C and 800°C for 5 minutes.

[0091] like Figures 7 and 8 As shown, the average sensitivity of the sensor in this embodiment is 12.89μV / (kW / m 2), with a T90 dynamic response time of approximately 1ms. Under the same heat flux density environment, the heat flux sensor of the present invention has a higher output and higher sensitivity than the Gordon meter GD-B5-5M. Because the Gordon meter has a water cooling device, it has better linearity and stability. However, the sensor of the present invention has better responsiveness to transient heat flux density changes.

[0092] like Figure 9 As shown, the output voltage of the heat flow sensor of the present invention at high temperature is much greater than the output voltage of the standard Gordon meter. The peak operating temperature of the water-free heat flow sensor of the present invention can reach 1385°C. When measuring heat flow, the output peak voltage of the sensor of the present invention at 1250°C is 3.23mV, while the output peak voltage of the Gordon meter GD-B5-5M is 0.976mV. In addition, Figure 9 The sensor of the present invention exhibits a decreasing output during the three temperature-maintaining stages at 400°C, 800°C, and 1400°C. This is because the sensor's temperature gradient gradually decreases during the temperature-maintaining stage, resulting in a decrease in the thermal output voltage and heat flux density. Therefore, while thermal stability is compromised compared to water-cooled heat flux sensor designs, the sensor of the present invention exhibits a higher transient response speed and greater thermal output for transient heat flux environments or scenarios with large variations in heat flux and temperature, facilitating in-situ testing.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-free, high-temperature heat flux-temperature synchronous measurement sensor, characterized in that: It comprises a functional layer (3), a thermal resistance layer (4) and a protective layer (5) which are arranged in sequence; The functional layer (3) is arranged on the surface of the substrate (1) by screen printing, and includes a first thermocouple lead electrode (11), a second thermocouple lead electrode (12), a first heat flow lead electrode (14), a second heat flow lead electrode (13), a plurality of positive sensitive electrodes (7) and a plurality of negative sensitive electrodes (8), wherein the positive sensitive electrodes (7) and the negative sensitive electrodes (8) are spaced apart and connected along a plurality of parallel straight lines to form a plurality of sequentially connected thermocouple pairs, and the electrodes at the head end or the tail end of each parallel straight line are symmetrically inclined and extended to connect with the electrodes on the adjacent parallel straight line to form an S-shaped curve arrangement; the diameter of the connection point at the end of the positive sensitive electrode (7) and the negative sensitive electrode (8) is larger than the electrode width; The first thermocouple lead electrode (11) and the second thermocouple lead electrode (12) are respectively connected to the positive sensitive electrode (7) and the negative sensitive electrode (8) of one of the thermocouple pairs; the first heat flow lead electrode (14) is connected to the positive sensitive electrode (7) at the beginning of the S-shaped curve, and the second heat flow lead electrode (13) is connected to the negative sensitive electrode (8) at the end of the S-shaped curve; The thermal resistance layer (4) is used to cover the functional layer (3), and a plurality of node slits (16) perpendicular to the straight line direction of the positive sensitive electrode (7) and the negative sensitive electrode (8) are provided on the thermal resistance layer (4), and the positions of the node slits (16) correspond to the positions of the hot nodes (9) of the thermocouple pair, and are used to expose the hot nodes (9); The diameter Φ of the connection point of the ends of the positive sensitive electrode (7) and the negative sensitive electrode (8) is 1.5b~2b, the electrode spacing d on two adjacent parallel straight lines is 2Φ~4Φ, and the length a of the positive sensitive electrode (7) and the negative sensitive electrode (8) is 4b~10b, wherein b represents the width of the positive sensitive electrode (7) and the negative sensitive electrode (8); and the optimization of the thermocouple logarithm is performed according to the following relationship to achieve optimization of sensitivity: ； ； Where, l represents the horizontal projection of the electrode, h represents the vertical projection of the electrode, h=2a, l =0, c represents the side length of the lead electrode; X and Y represent the length and width of the sensor; is the number of horizontal thermal nodes (9), is the number of vertical thermal junctions (9), and N represents the number of thermocouples; Electrode gaps for exposing the lead electrodes are provided at positions on the thermal resistance layer (4) corresponding to the first thermocouple lead electrode (11), the second thermocouple lead electrode (12), the first heat flow lead electrode (14), and the second heat flow lead electrode (13); a preparation method thereof comprises the following steps: Step 1: Cleaning the surface of the substrate (1); Step 2: Fix the screen printing mask of the positive sensitive electrode (7) on the surface of the substrate (1), evenly apply the positive sensitive electrode (7) slurry, and use a scraper to push back and forth at a uniform speed according to the pattern to obtain the positive sensitive electrode (7), the first thermocouple lead electrode (11) and the first heat flow lead electrode (14), and then dry and cool naturally; Step 3: After aligning the screen printing mask of the negative sensitive electrode (8) with the substrate (1), fix it on the surface of the substrate (1), evenly apply the negative sensitive electrode (8) slurry, and use a scraper to push it back and forth at a uniform speed according to the pattern to obtain a negative sensitive electrode (8) whose end connection point coincides with the end connection point of the positive sensitive electrode (7), a second thermocouple lead electrode (12) and a second heat flow lead electrode (13), and then dry it and cool it naturally to obtain a functional layer (3); Step 4: sintering the functional layer (3) at high temperature; Step 5: Place the thermal resistance layer mask above the functional layer (3), align it, and spray the thermal resistance material with a spray gun. After spraying, place it in the air to dry to obtain the thermal resistance layer (4); Step 6: Place the protective layer mask just above the thermal resistance layer (4), align it, and evenly apply the protective layer slurry, use a scraper to push it back and forth at a uniform speed according to the pattern, and then dry it; Step 7: Use high-temperature conductive glue to fix each electrode wire at the position of the first thermocouple lead electrode (11), the second thermocouple lead electrode (12), the first heat flow lead electrode (14), and the second heat flow lead electrode (13), and then solidify and sinter them. After cooling, take them out to complete the preparation of the heat flow sensor.

2. The water-free, high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: It also includes an insulating layer (2), which is arranged between the substrate (1) and the functional layer (3).

3. The water-free, high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: In the functional layer (3), the material of the first thermocouple lead electrode (11), the first heat flow lead electrode (14), and the positive sensitive electrode (7) is Pt-Rh10, and the material of the second thermocouple lead electrode (12), the second heat flow lead electrode (13), and the negative sensitive electrode (8) is Pt.

4. The water-free, high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: The protective layer (5) is obtained by screen printing an aluminum oxide slurry, and the thermal resistance layer (4) is a nano-composite ceramic material.

5. The water-free, high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: The step 1 further comprises the following steps: After the surface of the substrate (1) is cleaned, a high-temperature resistant insulating medium slurry is evenly applied to the surface of the substrate (1) through an insulating layer mask, and then dried, naturally cooled, and then sintered at a high temperature to obtain an insulating layer (2).

6. The water-free, high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: The preparation method further comprises the step of arranging a calibration mark (15) on the surface of the substrate (1).

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