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

Abstract

The invention belongs to the technical field of high-temperature sensing, and particularly relates to a water-cooling-free high-temperature-resistant heat flux-temperature synchronous measurement sensor and a preparation method thereof. The sensor comprises a functional layer, a thermal resistance layer and a protective layer which are arranged in sequence, the functional layer is arranged on the surface of the substrate through screen printing and comprises two thermocouple lead electrodes, two heat flow lead electrodes, a plurality of positive sensitive electrodes and a plurality of negative sensitive electrodes, and the positive sensitive electrodes and the negative sensitive electrodes are connected at intervals along a plurality of parallel straight lines to form thermocouple pairs; the electrode at the head end or the tail end on each parallel straight line symmetrically and obliquely extends to be connected with the electrode on the adjacent parallel straight line to form a thermocouple pair arranged in an S-shaped curve; the thermal resistance layer is used for covering cold nodes of the functional layer, a plurality of node seams are formed in the thermal resistance layer, the positions of the node seams correspond to the positions of the hot nodes of the thermocouple pairs, and the node seams are used for exposing the hot nodes. The sensor is simple to prepare, high in sensitivity and suitable for high-temperature and large-change heat flow field environments.

Description

Technical Field

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

[0002] High-temperature components in industrial fields such as aviation, aerospace, and automobiles, especially high-temperature rotating components such as engine blades and turbine disks, are prone to thermal fatigue and thermal damage, and then fission due to the continuous erosion of high-temperature gas flow on their surfaces. Therefore, accurately measuring their surface temperature and heat flux density is of great significance for the research on their reliability and safety. At present, common temperature measurements include non-contact temperature measurement technologies such as ultrasonic, fluorescence, infrared radiation, and radio frequency, and contact temperature measurement technologies such as irradiated crystals, temperature indicating paints, thin-film thermocouples, and platinum thermal resistors. For common heat flux measurements, that is, heat flux density tests, the sensor devices used include Gordon gauges, thermopile sensors, coaxial thermocouple heat flux meters, Schmidt-Boelter heat flux meters, etc. Most of the existing heat flux density test products require water cooling, have a relatively complex structure, and limited measurement accuracy.

[0003] With the development of micro-nano process (MEMS) technology and high-temperature-resistant and heat-insulating high-performance material technology, thin-film thermocouples and heat flux sensors have the characteristics of small size, high temperature resistance, excellent performance, and minimal impact on the on-site environment, and have greater advantages for real-time, continuous, and in-situ measurement of high-temperature parameters. In the prior art, there are sensors that integrate thermopiles and thermocouples to achieve synchronous measurement of heat flux density and temperature, but their processes are complex, it is difficult to directly prepare them on the surface of high-temperature components, and they are not suitable for in-situ measurement scenarios.

[0004] Therefore, it is necessary to invent a water-cooling-free high-temperature-resistant heat flux-temperature synchronous measurement sensor and a preparation method thereof to achieve 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 provides a water-cooling-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, in-situ preparation and in-situ measurement of the sensor are 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-cooling-free high-temperature-resistant heat flux-temperature synchronous measurement sensor, comprising a functional layer, a thermal resistance layer, and a protective layer arranged in sequence; The functional layer is disposed on the surface of the substrate by screen printing, and includes a first thermocouple lead electrode, a second thermocouple lead electrode, a first heat flux lead electrode, a second heat flux 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 connected at intervals along a plurality of parallel straight lines to form a plurality of sequentially connected thermocouple pairs. The electrodes located at the head or end of each parallel straight line symmetrically extend obliquely to be connected to the electrodes on the adjacent parallel straight lines to form an S-shaped curve arrangement. The diameters of the connection points at the ends of the positive sensitive electrodes and the negative sensitive electrodes are larger than the electrode widths. 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 flux lead electrode is connected to the positive sensitive electrode at the head of the S-shaped curve, and the second heat flux lead electrode is connected to the negative sensitive electrode at the end of the S-shaped curve. The thermal resistance layer is used to cover the functional layer, and a plurality of node slits perpendicular to the straight line directions where the positive sensitive electrodes and the negative sensitive electrodes are located are provided on the thermal resistance layer. The positions of the node slits correspond to the positions of the thermal nodes of the thermocouple pairs and are used to expose the thermal nodes.

[0007] The described water-cooled high-temperature resistant heat flux-temperature synchronous measurement sensor further includes an insulating layer, and the insulating layer is disposed between the substrate and the functional layer.

[0008] In the functional layer, the materials of the first thermocouple lead electrode, the first heat flux lead electrode, and the positive sensitive electrode are Pt-Rh10, and the materials of the second thermocouple lead electrode, the second heat flux lead electrode, and the negative sensitive electrode are Pt.

[0009] The protective layer is obtained by screen printing alumina paste, and the thermal resistance layer is a nano-composite ceramic material.

[0010] Electrode slits for exposing the lead electrodes are provided at the positions on the thermal resistance layer corresponding to the first thermocouple lead electrode, the second thermocouple lead electrode, the first heat flux lead electrode, and the second heat flux lead electrode.

[0011] The diameter Φ of the connection points at the ends of the positive sensitive electrodes and the negative sensitive electrodes is 1.5b to 2b, the electrode spacing between two adjacent parallel straight lines is 2Φ to 4Φ, where b represents the widths of the positive sensitive electrodes and the negative sensitive electrodes, and the lengths of the positive sensitive electrodes and the negative sensitive electrodes are 4b to 10b.

[0012] The present invention also provides a preparation method of a water-cooled high-temperature resistant heat flux-temperature synchronous measurement sensor for preparing the described water-cooled high-temperature resistant heat flux-temperature synchronous measurement sensor, including the following steps: Step 1: Clean the surface of the substrate. Step 2: Fix the screen printing mask of the positive sensitive electrode on the surface of the substrate, evenly apply the positive sensitive electrode paste, and use a squeegee to press and push back and forth uniformly according to the pattern to obtain the positive sensitive electrode, the first thermocouple lead electrode, and the first heat flux lead electrode with connection points at the ends, and then perform drying and natural cooling; 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 paste, and use a squeegee to press and push back and forth uniformly according to the pattern to obtain the negative sensitive electrode, the second thermocouple lead electrode, and the second heat flux lead electrode whose end connection points coincide with those of the positive sensitive electrode, and then perform drying, and obtain the functional layer after natural cooling; Step 4: Perform high-temperature sintering on the functional layer; Step 5: Set the thermal resistance layer mask above the functional layer, align it, and spray the thermal resistance material through a spray gun. After spraying, place it in the air to dry to obtain the thermal resistance layer; Step 6: Place the protective layer mask directly above the thermal resistance layer, align it, evenly apply the protective layer paste, and use a squeegee to press and push back and forth uniformly according to the pattern, and then perform drying; Step 7: Use high-temperature conductive adhesive to fix each electrode wire at the positions where the first thermocouple lead electrode, the second thermocouple lead electrode, the first heat flux lead electrode, and the second heat flux lead electrode are located respectively, and then perform curing and sintering. After cooling, take it out to complete the preparation of the heat flux sensor.

[0013] The said Step 1 further includes the following steps: After cleaning the surface of the substrate, evenly apply a high-temperature resistant insulating medium paste on the surface of the substrate through the insulating layer mask, and then perform drying, and perform high-temperature sintering after natural cooling to obtain the insulating layer.

[0014] The preparation method of the described water-cooled-free high-temperature resistant heat flux-temperature synchronous measurement sensor further includes the step of setting calibration marks on the surface of the substrate.

[0015] The present invention has the following beneficial effects compared with the prior art: 1. The invention proposes a water-cooled-free high-temperature resistant heat flux-temperature synchronous measurement sensor and its preparation method. By directly preparing the functional layer, the thermal resistance layer, and the protective layer on the base layer, where the functional layer includes a plurality of regularly arranged thermocouple pairs, it can not only realize the synchronous measurement of heat flux and temperature, but also, through the reasonable design of the thermocouple arrangement, on the premise of the same process, can greatly increase the number of thermocouples and the output of thermoelectromotive force, improve the sensitivity of the sensor, and for a continuous heat flow environment, the sensor of the present invention has a higher response speed and thermal output, and the water-cooled-free design is beneficial for in-situ testing.

[0016] 2. In the present invention, the sensor is prepared by screen printing. Compared with the sputtering process, it has better heat resistance. Its preparation process is simple, which is beneficial to realizing the in-situ preparation and testing of the sensor. In addition, it can also be used as an industrial non-in-situ test sensor and can be prepared on the surface of a thin ceramic substrate or a ceramic cavity with water cooling, having high response time and heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a schematic structural diagram of a water-cooling-free high-temperature-resistant heat flux-temperature synchronous measurement sensor provided in Embodiment 1 of the present invention; Figure 2 FIG. is a top view schematic diagram of the functional layer in Embodiment 1 of the present invention; Figure 3 FIG. is a top view schematic diagram of the functional layer covered with a thermal resistance layer in Embodiment 1 of the present invention; Figure 4 FIG. is a schematic circuit connection diagram for testing the sensor in Embodiment 1 of the present invention; Figure 5 FIG. is a schematic diagram of the electrode arrangement in the sensor; Figure 6 FIG. is a process flow chart of a sensor preparation method provided in Embodiment 2 of the present invention, where (a) represents the substrate cleaning process, (b) represents the insulating layer preparation process, (c) represents the insulating layer drying process, (d) represents the positive sensitive electrode preparation process of the functional layer, (e) represents the negative sensitive electrode preparation process of the functional layer, (f) represents the functional layer sintering process, (g) represents the thermal resistance layer preparation process, (h) represents the protective layer preparation process, and (j) represents the lead preparation process; Figure 7 FIG. is a schematic diagram for comparing the heat flux test sensitivity between the sensor of the present invention and a standard Gordon gauge; Figure 8 FIG. is a schematic diagram for comparing the linear fitting curve of the output voltage VS heat flux density between the sensor of the present invention and a Gordon gauge; Figure 9 FIG. is a schematic diagram of the output voltage of the heat flux density test and the corresponding thermocouple temperature of the sensor of the present invention and a Gordon gauge under the same test conditions.

[0018] In the figures: 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 flux lead electrode, 14 is the first heat flux lead electrode, 15 is the calibration mark, and 16 is the node seam. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1 As Figures 1 - 3 shown, an embodiment of the present invention provides a water-cooling-free high-temperature-resistant heat flux-temperature synchronous measurement sensor, which includes a functional layer 3, a thermal resistance layer 4, and a protective layer 5 arranged in sequence.

[0021] 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 flux lead electrode 13, a first heat flux 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. The electrodes at the head or tail ends on each parallel straight line symmetrically extend obliquely to be connected to the electrodes on the adjacent parallel straight lines to form thermocouple pairs arranged in an S-shaped curve; the connection points at the ends of the positive sensitive electrodes 7 and the negative sensitive electrodes 8 coincide to form a hot junction 9 or a cold junction 10; the diameter of the connection point is greater than the electrode width.

[0022] 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 flux lead electrode 14 is connected to the positive sensitive electrode 7 at the head end of the S-shaped curve, and the second heat flux lead electrode 13 is connected to the negative sensitive electrode 8 at the tail end of the S-shaped curve.

[0023] Specifically, the thermal resistance layer 4 is used to cover the functional layer 3, and a plurality of node slots 16 perpendicular to the straight line directions where the positive sensitive electrodes 7 and the negative sensitive electrodes 8 are located are arranged on the thermal resistance layer 4. The positions of the node slots 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 the positive sensitive electrodes 7 and the negative sensitive electrodes 8 on each parallel straight line is equal, so the positions of the hot junctions 9 on each straight line correspond, which is convenient for arranging the node slots 16.

[0024] Further, in this embodiment, when the substrate 1 is a conductor, the sensor further includes an insulating layer 2, and the insulating layer 2 is arranged between the substrate 1 and the functional layer 3.

[0025] Further, the sensor of this embodiment can not only be directly fabricated on the surface of the object to be measured. At this time, the surface of the object to be measured serves as the substrate 1 of the sensor. In addition, the sensor can also include a substrate 1 made of an insulating material and a housing. The functional layer 3, the thermal resistance layer 4, and the protective layer 5 are disposed on the substrate 1, and then the entire sensor is encapsulated through the housing. Moreover, a snap mechanism can be provided on the housing to fix the sensor at the position to be measured.

[0026] Specifically, in this embodiment, in the functional layer 3, the materials of the first thermocouple lead electrode 11, the first heat flux lead electrode 14, and the positive sensitive electrode 7 are Pt-Rh10, and the materials of the second thermocouple lead electrode 12, the second heat flux lead electrode 13, and the negative sensitive electrode 8 are Pt. As Figure 2 shown, the negative sensitive electrode 8 and the corresponding lead electrodes are represented by hatched lines. Further, in this embodiment, there can be two pairs of the first thermocouple lead electrode 11 and the second thermocouple lead electrode 12. By measuring the temperatures at different positions through the two pairs of lead electrodes, it is possible to detect whether the temperature at the measurement position is uniform, and thus preliminarily judge the stability of the heat flux environment of the sensor.

[0027] Specifically, in this embodiment, the protective layer 5 is obtained by screen printing alumina paste or silica paste, and the thermal resistance layer 4 is a nano-composite ceramic material.

[0028] Specifically, in this embodiment, electrode slots 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 flux lead electrode 14, and the second heat flux lead electrode 13 to expose these lead electrodes.

[0029] As Figure 4 shown, it is a schematic circuit connection diagram of the sensor of this embodiment. Among them, the heat flux density signals output by the first heat flux lead electrode 14 and the second heat flux lead electrode 13 and the temperature signals output by the first thermocouple lead electrode 11 and the second thermocouple lead electrode 12 are amplified and filtered by an amplifier, and then input to the FPGA for framing, encoding, storing and forwarding after being converted from analog to digital by an ADC converter, and then transmitted to a computer for data processing. In addition, the ADC converter is also connected to a platinum resistor R to correct the temperature signal.

[0030] Specifically, in this embodiment, the diameter Φ of the connection point is 1.5b to 2b, and the electrode spacing on two adjacent parallel lines is 2Φ to 4Φ, where b represents the width of the positive sensitive electrode 7 and the negative sensitive electrode 8, and the lengths of the positive sensitive electrode 7 and the negative sensitive electrode 8 are 4b to 10b.

[0031] In a limited space and on the premise that the process is determined, trying to design more thermocouple pairs as much as possible can improve the sensitivity and thermal output. Specifically, the expression of the sensitivity is: ; (1) Wherein, S k is the sensitivity of the heat flux sensor, μv / (W / ㎡); E is the thermoelectric potential output by the thermopile composed of the thermocouple array, μv; q is the heat flux density flowing in vertically; 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 has nothing to do with the temperature gradient difference Δ T and the sensor sensitivity can be obtained according to the thickness of the thermal resistance layer 4. The reason for the change in sensitivity is that the Seebeck coefficient S T will change due to the change in the ambient temperature. For transient test temperatures, it will not cause too much sensitivity fluctuation and can accurately measure the change in transient heat flux. And the larger the number of thermocouple pairs N within the same area, the greater the sensor sensitivity. Therefore, in the embodiments of the present invention, through reasonable design, the optimization of the sensitivity is achieved by optimizing the number of thermocouple pairs N within the same area to adapt to a high-temperature and large-variation heat flux field environment. The following introduces the optimization principle of the electrode design of the present invention.

[0032] N thermocouples form a group of thermopiles, and each thermocouple includes 2 sensitive electrodes made of different materials, namely the positive sensitive electrode 7 and the negative sensitive electrode 8. The positive sensitive electrode 7 and the negative sensitive electrode 8 are designed with the same size. As Figure 5 shown, assume that the length of each sensitive electrode is a, the width is b, and the included 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 Φ in diameter. Then there is: ; (2) 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 hot electrode is obvious, which is not conducive to the measurement of the heat flux density. In order to place as many thermocouple pairs as possible within a limited size, the length a of the electrode should not be too large either, otherwise the reliability will decrease. The number of pairs of the sensor is calculated based on the number n of the hot junctions 9, and can be calculated in combination with the sensor area X*Y (X Y) and the determined size of the hot electrode.

[0033] X is the length and Y is the width, is the number of horizontal thermal nodes 9, is the number of vertical thermal nodes 9. It can only take positive integers. Then there are: ; (3) Therefore, the value range of the number of thermocouple pairs N that can be included within the X*Y size is: ; (4) Taking into account the structure of the heat flux 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 is at least greater than 0.2 mm, and the edge blank distance is b . Assuming the length of the sensitive electrode a takes 4 b ~10 b , the diameter of the sensitive node Φ takes 1.5 b ~2 b , the horizontal center distance between nodes d takes 2 Φ ~4 Φ , the vertical distance between nodes of the same type h takes 3 Φ ~2 a , the side length of the lead electrode c is 3 b ~6b, and the width can be appropriately adjusted according to the actual lead requirements. h and l 's values are related to the angle , and the limit value is . Then the positive sensitive electrode 7 and the negative sensitive electrode 8 are on the same straight line. Assuming that among them: X = Y =20 mm, b =0.3 mm, a =6 b =1.8 mm, Φ =2 b ≈0.6 mm, and the limit value is , h =2 a =12 b , l =0, d= 2.33 Φ ≈1.4 mm, and the side length of the lead electrode c is 4 b , and the upper and lower margins are taken as b , and the left and right margins are Φ . Then there are: ; (5) Therefore, the present invention can be within 20×20 mm2 Implement 70 thermocouple pairs in terms of size. Finally, the length and width of the electrode leads are related to the lead diameter. The diameter of the external lead is taken to be less than 0.2 mm. If it is too thick, it is easy for the electrodes on the sensor substrate 1 to fall off due to stress.

[0034] Embodiment 2 As Figure 6 shown, Embodiment 2 of the present invention provides a preparation method of a water-cooled-free high-temperature-resistant heat flux-temperature synchronous measurement sensor for a water-cooled-free high-temperature-resistant heat flux-temperature synchronous measurement sensor described in Embodiment 1. It is prepared by a screen printing process, which greatly reduces the preparation difficulty and has good heat resistance. The specific steps are as follows: Step 1: Clean the surface of the substrate 1 and process the substrate 1.

[0035] In this embodiment, the substrate 1 is cleaned with plasma water and absolute ethanol by an ultrasonic cleaner and dried with lint-free paper.

[0036] In this embodiment, the method for processing the substrate 1 is as follows: The substrate 1 is placed in an incubator at 120 °C and dried for 15 - 30 minutes. After natural cooling, it is then placed in a muffle furnace for high-temperature sintering at a rate of 5 °C / min, and the peak temperature is maintained for more than 20 minutes. According to the heat resistance of the substrate 1, the peak temperature is bounded by the lower limit of the heat resistance of the substrate 1 or the insulating layer 2 slurry, generally taking more than 850 °C.

[0037] Step 2: Fix the screen printing mask plate of the positive sensitive electrode 7 on the surface of the substrate 1, evenly apply the positive sensitive electrode 7 slurry, and use a squeegee to press and push back and forth uniformly 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 flux lead electrode 14, and then dry and naturally cool.

[0038] In Step 2 of this embodiment, it is taken out after being placed in an incubator at 120 °C and dried for 15 - 30 minutes and waits for natural cooling.

[0039] Step 3: Align the screen printing mask plate 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 squeegee to press and push back and forth uniformly 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 flux lead electrode 13, and then dry. After natural cooling, the functional layer 3 is obtained.

[0040] Similarly, in Step 3, after screen printing, it is taken out after being placed in an incubator at 120 °C and dried for 15 - 30 minutes and waits for natural cooling to evaporate the solvent.

[0041] In this embodiment, the printing pastes of the positive sensitive electrode 7 and the negative sensitive electrode 8 are Pt-Rh10 and Pt respectively, such as ESL 5541-S and ESL 5541-A; when screen printing, a printing mask plate with 200 - 325 mesh, a tension of 30 N, and a film thickness of 20 μm is selected.

[0042] Step 4: Perform high-temperature sintering on the functional layer 3.

[0043] In this embodiment, after the functional layer 3 is prepared, the device is placed in a muffle furnace for high-temperature sintering, kept warm for 30 minutes, taken out after natural cooling, so that the organic solvents inside the paste are completely volatilized, the surface impurities are removed, and the metal sensitive electrodes are tightly attached to the surface of the insulating substrate. The sintering temperature is set according to the sintering temperature requirements of the sensitive electrode paste. Generally, the heat resistance of the sensitive electrode material is selected to be close to that of the substrate 1. In this embodiment, the high-temperature sintering temperature is 1350 °C and sintering is carried out for 30 min.

[0044] Step 5: Set the thermal resistance layer mask plate above the functional layer 3. After alignment, spray the thermal resistance material through a spray gun. After spraying is completed, place it in the air for 24 h to dry and obtain the thermal resistance layer 4.

[0045] Specifically, in the step 5, an air spray gun with a diameter of 0.8 mm and a pressure of 0.6 MPa is used to evenly spray the thermal resistance material perpendicular to the front of the mask plate. After spraying is completed, place it in the air for 24 h to dry. The thermal resistance layer 4 needs to select a material with a temperature resistance higher than that of the functional layer 3 and the insulating layer 2.

[0046] Specifically, the thermal resistance layer 4 is made of a nano-composite ceramic material. When preparing the thermal resistance layer 4, a mask plate with 200 - 250 mesh, a film thickness of 20 μm, and a tension of 30 N is used, and an air spray gun with a diameter of 0.8 mm and a pressure of 0.6 MPa is used, and it is naturally dried for 24 h.

[0047] Step 6: Place the protective layer mask plate directly above the thermal resistance layer 4. After alignment, evenly apply the protective layer paste, and use a squeegee to press and push back and forth uniformly according to the pattern, and then perform drying and high-temperature sintering.

[0048] Specifically, in the step 6, it is placed in an incubator at 120 °C and dried for 15 - 30 minutes to evaporate the solvent.

[0049] Specifically, the protective layer 5 selects alumina or other pastes with high thermal conductivity and high temperature resistance. When preparing the protective layer 5, a mask plate with 200 - 250 mesh, a film thickness of 5 μm, and a tension of 30 N is used, and the high-temperature sintering temperature is 1000 °C / 30 min.

[0050] In addition, in this embodiment, the thermal resistance layer mask plate and the protective layer mask plate can also be prepared with a flexible polyimide film.

[0051] Step 7: Fix each electrode wire at the positions where the first thermocouple lead electrode 11, the second thermocouple lead electrode 12, the first heat flux lead electrode 14, and the second heat flux lead electrode 13 are located with high-temperature conductive glue, then carry out curing sintering, take it out after cooling, and complete the preparation of the heat flux sensor.

[0052] In the said Step 7, fix the electrode wire with a diameter of φ0.1mm at the electrode position with high-temperature conductive paste, which is used to lead out the thermoelectromotive force output by the sensor to a high-precision acquisition device. After fixing, put it into a muffle furnace for sintering and curing for 0.5h, take it out after cooling, and complete the preparation of the heat flux sensor. The materials of the first heat flux lead electrode 14 and the first thermocouple lead electrode 11 are the same as those of the positive sensitive electrode 7; the materials of the second heat flux lead electrode 13 and the second thermocouple lead electrode 12 are the same as those of the negative sensitive electrode 8.

[0053] Furthermore, in this embodiment, when the substrate 1 is a conductor, the said Step 1 further includes the following steps: After the surface of the substrate 1 is cleaned, evenly apply a high-temperature resistant insulating medium paste on the surface of the substrate 1 through an insulating layer mask plate by screen printing process, then carry out drying, and carry out high-temperature sintering after natural cooling to obtain the insulating layer 2.

[0054] Furthermore, a preparation method of a water-cooled and high-temperature resistant heat flux-temperature synchronous measurement sensor in this embodiment further includes the step of setting a calibration mark 15 on the surface of the substrate 1. By setting the calibration mark 15, the alignment of each mask plate can be realized, and the preparation process precision can be improved. The calibration mark 15 can be set in the screen printing mask plate of the positive sensitive electrode 7.

[0055] In order to test the repeatability and stability of the sensor provided by the present invention, a heat flux sensor test system is built. 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 radiation heat source through a heating resistance wire, and calibrates the heat flux density and the ambient temperature of the radiation source through a standard Gordon meter and an S-type thermocouple. The heat flux sensor to be tested and the Gordon meter are fixed at the center of the furnace mouth of the muffle furnace through mullite, and the sensitive surfaces are kept in the same vertical plane so that both are exposed to the same radiation heat flux environment. The S-type standard thermocouple is fixed in the center of the mullite brick and is used to provide the accurate working environment temperature of the heat flux sensor. The data acquisition device cooperates with the test computer to synchronously complete the thermoelectromotive force signals output by the S-type thermocouple, the Gordon meter and the HTHFS, and evaluate the performance of the heat flux sensor by comparison. The upper limit of the test temperature of the heat flux sensor is set to 1400°C.

[0056] The average sensitivity of the standard Gordon meter is 2.45 μV / (kW / m2 ), with a measurable upper limit of 5 MW / m 2 of heat flux density. Cold water at 20 - 25 °C is circulated at a flow rate of 3 L / min at the rear end of the probe through a water cooling device to ensure the stable output of the heat flux meter. The Gordon meter has advantages such as good linearity and high stability, and can be used as a reference device for HTHFS calibration. The heating rate of the muffle furnace is 5 °C / min and 10 °C / min respectively in the temperature ranges of (50 - 400) °C and (400 - 1400) °C, and it is insulated for 5 minutes at 400 °C and 800 °C.

[0057] As Figures 7 - 8 shown, the average sensitivity of the sensor in this embodiment is 12.89 μV / (kW / m 2 ), the T90 dynamic response time is about 1 ms. In an environment with the same heat flux density, the heat flux sensor of the present invention has a larger output and higher sensitivity than the Gordon meter GD - B5 - 5M. Since the Gordon meter has a water cooling device, its linearity and stability are better. However, for transient changes in heat flux density, the sensor of the present invention has a better response.

[0058] As Figure 9 shown, the output voltage of the heat flux sensor of the present invention in the high - temperature stage is much larger than the output voltage of the standard Gordon meter. The peak working temperature of the water - free heat flux sensor of the present invention can reach 1385 °C. When measuring heat flux, the peak output voltage of the sensor of the present invention is 3.23 mV at 1250 °C, and the peak output voltage of the Gordon meter GD - B5 - 5M is 0.976 mV. In addition, Figure 9 in this invention, during the three insulation stages of the sensor at 400 °C, 800 °C and 1400 °C, there is a trend of decreasing output. This is because during the temperature - holding stage, the temperature gradient of the sensor gradually decreases, resulting in a decrease in the thermal output voltage and heat flux density. Therefore, compared with the design of the water - cooled heat flux sensor, although the thermal stability is affected, for transient heat flux environments or scenarios with large changes in heat flux and temperature, the sensor of the present invention has a higher transient response speed and a larger thermal output, which is beneficial for in - situ testing.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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 comprises 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 connected at intervals along a plurality of parallel straight lines to form a plurality of thermocouple pairs connected in sequence, and the electrodes located at the head end or the end end of each parallel straight line are symmetrically inclined and extended to be connected to the electrodes on the adjacent parallel straight lines 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 greater 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 where the positive sensitive electrode (7) and the negative sensitive electrode (8) are located 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, so as to expose the hot nodes (9).

2. The water-free high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: It also comprises an insulating layer (2), wherein the insulating layer (2) 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: Electrode slits 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).

6. The non-water-cooled high-temperature heat flux-temperature synchronous measurement sensor according to claim 1, characterized in that: The diameter Φ of the connection point at the ends of the positive sensitive electrode (7) and the negative sensitive electrode (8) is 1.5b~2b, and the distance between the electrodes on two adjacent parallel straight lines is 2Φ~4Φ, wherein 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.

7. A method for preparing a water-free high-temperature heat flux-temperature synchronous measurement sensor, characterized in that: The method for preparing a water-free high-temperature heat flux-temperature synchronous measurement sensor according to claim 1 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 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 and cool naturally to obtain a functional layer (3); Step 4: sintering the functional layer (3) at high temperature; Step 5: placing the thermal resistance layer mask above the functional layer (3), aligning and spraying the thermal resistance material with a spray gun, and after spraying, placing 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.

8. The method for preparing a water-free high-temperature heat flux-temperature synchronous measurement sensor according to claim 7, characterized in that: The step 1 also includes 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).

9. The method for preparing a water-free high-temperature heat flux-temperature synchronous measurement sensor according to claim 7, characterized in that: The method further comprises the step of providing a calibration mark (15) on the surface of the substrate (1).

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