Long electric heating plate heat insulation structure and heat transfer simulation experiment device with same

Abstract

The invention relates to the technical field of reactor thermal hydraulics and safety, in particular to a long electric heating plate heat insulation structure and a heat transfer simulation experiment device with the long electric heating plate heat insulation structure. The long electric heating plate heat insulation structure comprises a heat insulation base, a heating plate and a cementing layer. The heat insulation base is configured to be a ceramic resin plate, and a sinking groove is formed in one plate face of the heat insulation base. The heated plate is arranged in the sinking groove so that the plate face of the heated plate can be flush with the plate face of the heat insulation base, and the surface, corresponding to the groove wall and the groove bottom of the sinking groove, of the heated plate is provided with a micropore aluminum oxide ceramic layer which is subjected to nanocrystallization treatment through an active coupling agent. And the cementing layer is arranged between the heated plate and the heat insulation base in a high-temperature vacuum pressure environment. According to the heat transfer simulation experiment device, it can be ensured that the heated plate has good single-side heat dissipation performance under the temperature working condition that the surface of the dispersion type fuel element is blistered, the experiment safety during operation of the heat transfer simulation experiment device can be ensured, and the accuracy of a measurement result in a simulation experiment can be ensured.

Description

Technical Field

[0001] The present application relates to the field of reactor thermal hydraulics and safety technology, and in particular to a long electric heating plate insulation structure and a heat transfer simulation experimental device having the same. Background Art

[0002] Rectangular narrow slit channels have the advantages of compact structure and large heat exchange area, and have been widely used in heat exchangers and nuclear reactor fuel assemblies. However, due to factors such as the corner effect of the rectangular narrow slit channel, its flow heat transfer characteristics, including the critical heat flux value, are significantly different from those of the corresponding hydraulic diameter circular tube channel. It is necessary to carry out special experiments on flow heat transfer and critical heat flux in rectangular channels. This type of experiment usually uses a long metal plate with a large aspect ratio for heating, and the insulation of the metal plate is an important factor in ensuring the safety of the experiment. In addition, this type of experiment often uses a single-sided heating simulation experiment. It is necessary to ensure that the heat generated by the metal plate entering the coolant channel through a single heating surface as much as possible, that is, the other surfaces of the metal plate are non-heating surfaces, and all require insulation. At present, most experimental models use ceramic plates or polytetrafluoroethylene plates to form a partition to achieve insulation and thermal insulation of the electric heating plate. However, the splicing method is relatively complicated, and the dimensional tolerance and installation accuracy of the spliced ​​plate are high. The joints may also cause water leakage in the experimental piece and affect the thermal insulation performance, which not only endangers the safety of the experiment, but also affects the accuracy of the measurement results such as the heating wall temperature. Summary of the invention

[0003] The present application provides a long electric heating plate insulation structure and a heat transfer simulation experimental device having the same, which uses gluing to achieve a sealed connection between the heating plate and the insulation base, reduces the dimensional tolerance and installation accuracy requirements of the heating plate and the insulation base, and reduces the risk of water leakage at the joints, thereby solving the problem that the existing splicing method endangers the test safety and affects the accuracy of measurement results such as the heating wall temperature.

[0004] This application is implemented through the following technical solutions:

[0005] In a first aspect, the present application provides a long electric heating plate insulation structure, comprising:

[0006] A heat-insulating base, wherein the heat-insulating base is configured as a ceramic resin plate, and a sink groove is provided on one plate surface of the heat-insulating base;

[0007] A heat receiving plate, the heat receiving plate is arranged in the sink so that the plate surface of the heat receiving plate is flush with the plate surface of the insulation base, and a microporous alumina ceramic layer nano-processed with an active coupling agent is arranged on the surface of the heat receiving plate corresponding to the wall and bottom of the sink;

[0008] The adhesive layer is arranged between the heated plate and the insulating base under a high-temperature vacuum pressure environment.

[0009] In some optional embodiments, the thickness of the microporous alumina ceramic layer is configured to be 10-50 μm.

[0010] In some optional embodiments, the aspect ratio of the micropores in the microporous alumina ceramic layer is configured to be in the micron level.

[0011] In some optional embodiments, the groove wall and the groove bottom of the sink are configured as laser activated surfaces.

[0012] In a second aspect, the present application provides a heat transfer simulation experimental device for simulating the bubbling condition on the surface of a dispersed fuel element, comprising:

[0013] Any one of the long electric heating plate insulation structures described in the first aspect, wherein the plate surface of the heating plate away from the insulation base has a vacuum bubble portion, the insulation base is provided with an elastic sealing cavity, the elastic sealing cavity is filled with insulation powder, and the insulation base is also provided with a temperature measuring hole corresponding to the position of the vacuum bubble portion, so that the thermocouple can pierce the elastic sealing cavity through the temperature measuring hole and contact the heating plate;

[0014] A cover body, wherein the cover body has a flow slot, the cover body is connected to the heat-insulating base so that the heat-insulating base seals the flow slot to form a narrow slit channel, and the heated plate is located in the narrow slit channel;

[0015] A medium introduction member, the medium introduction member being in communication with one end of the narrow slit channel;

[0016] A medium outlet member, the medium outlet member being in communication with the other end of the narrow slit channel;

[0017] Conductive members, two of which are connected to two ends of the heated plate respectively, and the vacuum bubble portion is located between the two conductive members.

[0018] In some optional embodiments, the cover body is sealed to the insulation base via a static sealing ring, wherein the static sealing ring is arranged around the flow groove.

[0019] In some optional embodiments, the light transmittance of the cover body is configured to be no less than 98%.

[0020] In some optional embodiments, the cover is configured as optical quartz glass.

[0021] In some optional embodiments, the conductive member is connected to the heated plate by silver brazing.

[0022] In some optional embodiments, the number of the temperature measuring holes is configured to be multiple, and in the normal viewing angle of the heated plate surface, the distance between the multiple temperature measuring holes and the vacuum bubble portion is no more than 10 mm.

[0023] In some optional embodiments, at least one temperature measuring hole corresponds to a center position of the vacuum bubble.

[0024] In some optional embodiments, the insulating base has a removable positioning plate, which includes a lower baffle and an upper baffle embedded in the lower baffle, and an installation cavity suitable for accommodating the elastic sealing cavity is formed between the upper baffle and the lower baffle, and the temperature measuring hole is located on the positioning plate; wherein the positioning plate corresponds to the position of the vacuum bubble portion.

[0025] In some optional embodiments, a pressure measuring tube is further included, and the pressure measuring tube is connected to the narrow slit channel.

[0026] In some optional embodiments, the medium inlet and / or medium outlet is equipped with a temperature measuring tube.

[0027] In some optional embodiments, it further includes a first pressure block and a second pressure block arranged at intervals, the first pressure block is connected to the second pressure block, wherein the first pressure block abuts against the base, and the second pressure block abuts against the cover body.

[0028] In some optional embodiments, the heated plate comprises:

[0029] A foaming plate, wherein the foaming plate is formed with a groove by a casting process;

[0030] A heating plate, wherein the heating plate and the bubbling plate are arranged in parallel and spaced apart from each other;

[0031] An insulating layer is located between the blister plate and the heating plate, the insulating layer is connected to the heating plate, and the insulating layer and the blister plate are connected by vacuum diffusion welding to enclose a vacuum bubble portion with the groove on the blister plate.

[0032] Compared with the prior art, this application has the following advantages and beneficial effects:

[0033] 1. The long electric heating plate insulation structure provided by the present application has a heating plate that is sealed and connected to an insulating base by gluing, which greatly reduces the dimensional tolerance and installation accuracy requirements for the heating plate and the insulating base; the microporous alumina ceramic layer can be tightly connected to the heating plate, and the gluing layer can combine with the active coupling agent in the micropores under a high-temperature vacuum pressure environment, so that the gluing layer can have a greater connection strength with the heating plate, thereby ensuring that the insulating base can have a greater connection strength with the heating plate to meet the temperature under the bubbling condition of the dispersed fuel element, and avoiding the gluing layer from being separated from the heating plate under high temperature conditions.

[0034] 2. The heat transfer simulation experimental device provided in the present application, the vacuum bubble-like portion on the heated plate can simulate the structural state of the diffuse fuel element under bubbling, and a narrow slit channel is formed by connecting the cover body and the insulating base, and the medium inlet and outlet parts are used to realize the flow of the medium in the narrow slit channel, and the conductive part is used to realize the heating of the heated plate. At the same time, the heated plate realizes unilateral diffusion of heat to the narrow slit channel under the insulating effect of the insulating base, and can obtain the same heating conditions and heat transfer conditions as those when the diffuse fuel element is bubbling, and provide a coolant thermal boundary consistent with that when the diffuse fuel element is bubbling, thereby realizing accurate simulation of the heating boundary of the diffuse fuel element and the geometric boundary of the flow channel, and finally, the setting of the temperature measuring hole can conveniently realize the direct measurement of the temperature of the heated plate.

[0035] 3. In the heat transfer simulation experimental device provided in the present application, the temperature measuring element is external, and the temperature measuring element does not need to be continuously in a high-temperature working environment, which is conducive to improving the accuracy of temperature measurement; after the measurement is completed, the elastic sealing cavity compresses the insulating powder inside it through its own elasticity to fill the holes formed by the puncture of the temperature measuring element, thereby avoiding heat loss from the heated plate and ensuring that the thermal boundary of the coolant in the narrow channel is basically consistent with the actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0037] Figure 1 A schematic cross-sectional structure diagram of the insulation structure of the Changdian heating plate provided in the embodiment of the present application;

[0038] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at C in the middle;

[0039] Figure 3 A schematic diagram of the structure of a heat transfer simulation experimental device provided in an embodiment of the present application;

[0040] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at AA in the middle;

[0041] Figure 5 A schematic diagram of a partial structure of the connection between the positioning plate and the first pressure-bearing block provided in an embodiment of the present application;

[0042] Figure 6 A schematic diagram of the cross-sectional structure of a positioning plate provided in an embodiment of the present application;

[0043] Figure 7 This is a schematic diagram of the heated plate structure provided in an embodiment of the present application.

[0044] Marks and corresponding parts names in the attached drawings:

[0045] 1-medium inlet, 2-medium outlet, 3-second pressure-bearing block, 4-cover, 5-heating plate, 51-bubble plate, 52-heating plate, 53-insulating layer, 6-insulating base, 7-narrow slit channel, 8-conductive member, 9-first pressure-bearing block, 10-temperature measuring hole, 11-positioning plate, 111-upper baffle, 112-lower baffle, 113-elastic sealing cavity, 114-insulating powder, 12-temperature measuring pipe, 13-pressure measuring pipe, 14-bonding layer, 15-microporous alumina ceramic layer. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with examples and drawings. The illustrative implementation scheme of the present application and its description are only used to explain the present application and are not intended to limit the present application.

[0047] First, please refer to Figure 1 and Figure 2 An embodiment of the present application provides a long electric heating plate insulation structure, including an insulation base 6, a heating plate 5 and an adhesive layer 14.

[0048] The insulating base 6 is configured as a ceramic resin plate, which means that the overall shape of the insulating base 6 is plate-like. The ceramic resin plate has good heat resistance, wear resistance, impact resistance, and processability, and is suitable for processing long-length plates; a recessed groove is provided on one of the plate surfaces of the insulating base 6.

[0049] The heated plate 5 can be configured as a metal plate that can be electrically conductive. The heated plate 5 is arranged in the sink so that the plate surface of the heated plate 5 is flush with the plate surface of the insulating base 6. A microporous alumina ceramic layer 15 that has been nano-treated using an active coupling agent is arranged on the surface of the heated plate 5 corresponding to the sink wall and the bottom of the sink.

[0050] The adhesive layer 14 is disposed between the heated plate 5 and the insulating base 6 under a high temperature vacuum pressure environment.

[0051] In the embodiment of the present application, the heated plate 5 is a conductive metal plate with a relatively smooth surface. Therefore, if the adhesive is directly bonded to the heated plate 5, there will be problems such as low connection strength and insufficient bonding degree of the connection surface. That is, on the one hand, after the adhesive is cured and formed, there is a small gap between it and the surface of the heated plate 5, which makes the actual heat dissipation area of ​​the heated plate 5 larger. On the other hand, the bonding point between the adhesive and the heated plate 5 may debond under long-term high temperature conditions, so that the gap expands, further increasing the heat dissipation area, which will greatly affect the unilateral heat dissipation effect of the heated plate 5. However, by first bonding the microporous alumina ceramic layer 15 to the heated plate 5, the microporous alumina ceramic layer 15 and the heated plate 5 have a greater bonding strength, and the bonding Tighter, the microporous alumina ceramic layer 15 is nano-processed by an active coupling agent, and the adhesive can enter the micropores of the microporous alumina ceramic layer 15 under a high-temperature vacuum pressure environment to combine with the active coupling agent. The adhesive and the microporous alumina ceramic layer 15 have a stronger bonding strength and a relatively high bonding tightness, so that there are fewer or no tiny gaps between the adhesive and the heated plate 5. After the adhesive is combined with the active coupling agent in the micropores, the adhesive and the microporous alumina ceramic layer 15 will not be easily separated under high temperature (i.e., the operating temperature of the foaming of the dispersed fuel element), thereby ensuring that the heated plate 5 has a good one-sided heat dissipation effect, ensuring the safety of the test, and ensuring the accuracy of the measurement results.

[0052] In the embodiment of the present application, the heated plate 5 can also be configured as a non-metallic conductive plate such as silicon, germanium, silicon carbide, gallium arsenide, carbon fiber, graphite, carbon nano, ceramic fiber, carbon-based composite plate, etc.

[0053] In the embodiment of the present application, the insulating base 6 is configured in a plate shape in order to facilitate processing and reduce the space occupied by the overall insulating structure. In other embodiments, the shape of the insulating base 6 is not limited, and the shape of the insulating base 6 does not affect its insulating performance for the heated plate 5, which means that in the present application, in order to achieve the insulating effect for the heated plate 5, insulating bases 6 of other shapes can be equivalent to the plate-shaped insulating base 6.

[0054] In some optional embodiments, the thickness of the microporous alumina ceramic layer 15 can be configured to be 10 to 50 μm to ensure the connection strength between the microporous alumina ceramic layer 15 and the heated plate 5 and the connection strength between the microporous alumina ceramic layer 15 and the adhesive. At the same time, the smaller microporous alumina ceramic layer 15 can reduce heat loss and ensure the single-sided heat dissipation effect of the heated plate 5.

[0055] In some optional embodiments, the depth-to-diameter ratio of the micropores in the microporous alumina ceramic layer 15 can be configured to be at the micron level, thereby ensuring that the microporous alumina ceramic layer 15 and the bonding layer 14 have a larger bonding surface area, while ensuring that the bonding layer 14 and the microporous alumina ceramic layer 15 have a better mechanical locking effect, thereby ensuring the connection strength between the bonding layer 14 and the microporous alumina ceramic layer 15.

[0056] In some optional embodiments, the groove wall and the groove bottom of the groove are configured as laser-activated surfaces, and the laser-activated surface can further improve the connection strength between the adhesive layer 14 and the insulation base 6.

[0057] Second, please refer to Figure 1 to Figure 4 An embodiment of the present application provides a heat transfer simulation experimental device for simulating the bubbling condition on the surface of a dispersed fuel element. The heat transfer simulation experimental device includes a cover body 4, a medium inlet member 1, a medium outlet member 2, a conductive member 8 and any one of the long electric heating plate insulation structures described in the first aspect.

[0058] One of the surfaces of the heating plate 5 in the long electric heating plate insulation structure has a vacuum bubble, which is manifested as a hollow protrusion on one of the surfaces of the heating plate 5. The vacuum bubble can be formed by casting or by connecting two components. The hollow protrusion is a vacuum cavity. Preferably, the heating plate 5 is formed by welding two plates, one of which is used for connection, and the other plate can be welded to one of the plates after forming a protrusion by casting.

[0059] See also Figure 6The plate surface of the sink groove is provided on the insulation base 6 as the working surface, and an elastic sealing cavity 113 is provided in the insulation base 6. The elastic sealing cavity 113 can be made of rubber or silicone material. The elastic sealing cavity 113 is filled with insulation powder 114. In actual implementation, the insulation powder 114 can be configured as glass fiber powder. The insulation base 6 is also provided with a temperature measuring hole 10 corresponding to the position of the vacuum bubble portion. The thermocouple can pierce the elastic sealing cavity 113 through the temperature measuring hole 10 and contact the heated plate 5. In actual implementation, a puncture hole with a diameter much smaller than that of the thermocouple can be provided on the elastic sealing cavity 113. Due to the material properties of the elastic sealing cavity 113 itself, the thermocouple pierces the elastic sealing cavity 113. After the elastic sealing cavity 113 is formed, the wall of the puncture hole can be tightly attached to the thermocouple due to its own elastic deformation. At the same time, the thermal insulation powder 114 in the elastic sealing cavity 113 is more compact under the pressure of the thermocouple, which means that the thermal insulation powder 114 can also be tightly attached to the thermocouple. Of course, since the thermal insulation powder 114 is compressed, the cavity wall of the elastic sealing cavity 113 will also be compressed by the thermal insulation powder 114 to undergo a certain elastic deformation. After the temperature measurement is completed, the thermocouple is taken out, and the puncture hole of the elastic sealing cavity 113 returns to its original state under the action of the elastic deformation, while the internal thermal insulation powder 114 is compressed under the elastic action of the cavity wall of the elastic sealing cavity 113, which prompts the thermal insulation powder 114 to flow to the thermocouple. The formed hole means that under the elastic action of the elastic sealing cavity 113, the insulating powder 114 can be self-filled, thereby providing a better insulating effect on the heated plate 5, avoiding heat loss of the heated plate 5, and ensuring that the thermal boundary of the coolant in the narrow slit channel 7 is basically consistent with the actual working condition. A ceramic tube can be inserted in the temperature measuring hole 10 to achieve the insulation function. The extension direction of the temperature measuring hole 10 can be unlimited, such as a straight line, a broken line, a curve or a combination of any two / three of the above. In order to reduce the length of the temperature measuring hole 10 in its extension direction, the extension direction of the temperature measuring hole 10 can be a straight line, wherein the extension direction of the temperature measuring hole 10 can be perpendicular to the plate surface of the heated plate 5 or form an angle. In actual implementation It is preferred that the extension direction of the temperature measuring hole 10 is set to be perpendicular to the plate surface of the heated plate 5, so as to ensure that the length of the temperature measuring hole 10 in the extension direction is short enough, so that the temperature measurement of the heated plate 5 can be carried out in the temperature measuring hole 10. When the temperature measuring hole 10 is not working, it can be isolated. The shorter temperature measuring hole 10 can ensure that there is less heat exchange medium inside in the isolated state, such as air, so as to reduce the influence of the air on the local temperature of the heated plate 5 during the test. The cross-sectional shape of the temperature measuring hole 10 can be unlimited, such as triangle, rectangle, square, circle, heart, star or other special shapes. In actual implementation, the temperature measuring hole 10 can be set to a circular straight hole.

[0060] The cover body 4 has a circulation groove, and the cover body 4 is connected to the insulating base 6 so that the insulating base 6 seals the circulation groove to form a narrow slit channel 7, and the heated plate 5 is located in the narrow slit channel 7, that is, for the cover body 4 and the heated plate 5, the heated plate 5 can be placed in the circulation groove; the specific form of the circulation groove is not limited, it can be a closed groove body on the cover body 4, that is, there is only one groove, or it can be an open groove body, that is, the circulation groove can penetrate the cover body 4 to form two / three grooves; in actual implementation, the circulation groove can be set as a closed groove body, so that after the cover body 4 is connected to the insulating base 6, the insulating base 6 can easily seal the circulation groove through the working surface to form a narrow slit channel 7. Of course, in other embodiments, if the circulation groove is set as an open groove body, then after the cover body 4 is connected to the insulating base 6, other grooves can be sealed separately or other grooves can be connected to it. The other components are sealed and connected; the specific shape of the circulation groove may not be limited, such as triangle, rectangle, square, circle or other special shapes; since a narrow slit channel 7 for the medium to flow will be formed between the circulation groove and the insulating base 6, it is preferred to set the circulation groove to a trough shape with a certain length, such as a rectangular trough body, a square trough body, a prismatic trough body, preferably, the circulation groove is set to a rectangular trough body or a square trough body, that is, from the perspective of the length direction of the circulation groove, the contour shape of the circulation groove is square or rectangular, wherein, when the circulation groove is set to a rectangular trough body or a square trough body, its extension direction can be a straight line or a curve, in actual implementation, the extension direction of the circulation groove can be set to a straight line to ensure that the medium has a stable flow state in the narrow slit channel 7, and in other embodiments, as needed, the extension direction of the circulation groove can also be set to a curve or a combination of a curve and a straight line. When the circulation groove is set as a rectangular groove body or a square groove body, the heated plate 5 can be set as a rectangular plate body, that is, the thickness of the heated plate 5 is uniform except for the position of the vacuum bubble portion. At this time, the overall shape of the narrow slit channel 7 formed by the circulation groove and the insulating base 6 is a rectangular parallelepiped, which is conducive to the centering of the heated plate 5 in the narrow slit channel 7, ensuring that the heat can be evenly diffused in the narrow slit channel 7, and ensuring that the medium is evenly heated in the flow direction.

[0061] The medium introduction member 1 is connected to one end of the narrow slit channel 7; when the circulation slot is set as a closed slot body, the medium introduction member 1 can pass through the insulation base 6 to communicate with the narrow slit channel 7, and the medium introduction member 1 is sealed and connected to the insulation base 6; when the circulation slot is set as an open slot body, the medium introduction member 1 can be directly sealed and connected to the unclosed slot in the circulation slot. The medium introduction member 1 is usually used for injecting coolant.

[0062] The medium outlet component 2 is connected to the other end of the narrow slit channel 7; when the circulation slot is set as a closed slot body, the medium outlet component 2 can pass through the insulating base 6 to be connected to the narrow slit channel 7, and the medium outlet component 2 is sealed to the insulating base 6; when the circulation slot is set as an open slot body, the medium outlet component 2 can be directly sealed to the unclosed slot in the circulation slot.

[0063] The two conductive members 8 are respectively connected to the two ends of the heated plate 5. The conductive members 8 can be configured as copper bars, aluminum bars, stainless steel bars, zinc alloy bars, copper alloy bars, plastic conductive bars, etc. In actual implementation, the two conductive members 8 can be the same or different. Preferably, the two conductive members 8 can be configured as copper bars. Copper bars have excellent electrical conductivity, can reduce heat loss, and have good mechanical strength, corrosion resistance, high flexibility and good welding performance; the vacuum bubble portion is located between the two conductive members 8, that is, when the heated plate 5 is set as a rectangular plate body, the two conductive members 8 can be connected at both ends of the heated plate 5 in the length direction, and in the length direction of the heated plate 5, the vacuum bubble portion can be located in the middle position of the two conductive members 8. Of course, in other embodiments, the vacuum bubble portion can also be located at other positions between the two conductive members 8.

[0064] The heat transfer simulation experimental device provided in the embodiment of the present application is a heat transfer simulation experimental device. The vacuum bubble portion on the heated plate 5 can simulate the structural state of the dispersed fuel element under the bubbling condition. After connecting the two conductive parts 8 to the power supply and connecting the medium inlet part 1 and the medium outlet part 2 to the medium circulation system, the heated plate 5 can be electrically conducted to generate heat, thereby achieving a temperature increase. Due to the insulation effect of the insulation base 6, most of the heat of the heated plate 5 is dissipated to the narrow slit channel 7 on one side to heat the medium in the narrow slit channel 7, thereby simulating the working state of the fluid in the dispersed fuel element. The experimenter can measure the temperature field of the medium near the vacuum bubble portion, and directly measure the temperature of the heated plate 5 at the corresponding position of the vacuum bubble portion through the temperature measuring hole 10, and combine the parameters such as the medium pressure and medium flow rate in the medium circulation system to obtain the flow heat transfer characteristics near the vacuum bubble portion. The flow heat transfer characteristics can provide technical support for the precise formulation of thermal hydraulic design and safety criteria of dispersed fuel elements.

[0065] Compared with the existing three-dimensional numerical simulation method, the heat transfer simulation experimental device provided in the embodiment of the present application can perform direct measurement, has relatively less calculation amount, is relatively more convenient to implement, the data is more intuitive and easier to obtain, and the measurement results are quite credible.

[0066] There are various ways of sealing the connection between the cover body 4 and the insulating base 6, for example, adhesive sealing, welding sealing, magnetic sealing, and threaded sealing can be used. Considering the maintainability of the entire device, in some optional embodiments, the cover body 4 is sealed and connected to the insulating base 6 through a static sealing ring. The static sealing ring can be configured as a rubber sealing ring, a metal sealing ring, a polytetrafluoroethylene sealing ring, a graphite sealing ring, etc. In actual implementation, a suitable static sealing ring can be selected according to the thermal conductivity of the cover body 4. For example, if the thermal conductivity of the cover body 4 is low, a static sealing ring with average heat resistance, such as a rubber sealing ring, can be selected. When the thermal conductivity of the cover body 4 is high, a static sealing ring with high heat resistance, such as a graphite sealing ring, can be selected. In actual implementation, it is usually expected that the thermal conductivity of the cover body 4 is low. In order to avoid a large amount of heat loss in the narrow slit channel 7, that is, in the working state, the temperature of the cover body 4 will not be too high, and the static sealing ring can be configured as a low-cost static sealing ring such as a rubber sealing ring; wherein, the static sealing ring is arranged around the circulation groove, and the shape of the static sealing ring can be not limited. For example, the static sealing ring can be such as rectangular, circular, triangular, diamond, etc., and can be specifically designed according to the adaptability of the notch of the circulation groove to avoid a large slit space after the cover body 4 is connected to the insulating base 6; for example, when the circulation groove is a rectangular groove body, its notch is rectangular, and the static sealing ring can be configured as a rectangle. Of course, in other embodiments, according to needs, such as different installation conditions and different processing accuracy, the shape of the static sealing ring can also be other special shapes.

[0067] The cover 4 can be configured as a transparent or opaque material, and both can realize the measurement of parameters such as the temperature of the medium in the narrow slit channel 7. Of course, if the cover 4 has a certain degree of transparency, it can realize the visual measurement of the velocity field and two-phase flow of the medium in the narrow slit channel 7. Therefore, in some optional embodiments, the light transmittance of the cover 4 is configured to be not less than 98%. Preferably, the cover 4 can be configured as optical quartz glass. On the basis of having good light transmittance performance, optical quartz glass also has low thermal conductivity, which can reduce the heat loss of the medium in the narrow slit channel 7.

[0068] The conductive member 8 is usually connected to other devices with conductive requirements by welding. The heated plate 5 in the embodiment of the present application has a relatively high temperature in the working state, so the welding between the conductive member 8 and the heated plate 5 should have a certain heat resistance. In some optional embodiments, the conductive member 8 is connected to the heated plate 5 by silver brazing. The thermal expansion coefficient of silver is smaller than that of copper, which means that when the temperature changes, the thermal stress generated by the silver brazing connection point is relatively small, which helps to reduce the risk of loose connection, and silver has good corrosion resistance, especially in high temperature environment, which helps to extend the service life of the welding part and ensure the conductive performance of the conductive member 8 and the heated plate 5.

[0069] In order to conveniently obtain the temperature field characteristics of the vacuum bubble and its surroundings, in some optional embodiments, the number of the temperature measuring holes 10 is configured to be multiple, and in the normal viewing angle of the surface of the heated plate 5, the spacing between the multiple temperature measuring holes 10 and the vacuum bubble is not greater than 10 mm; it includes the temperature measuring holes 10 corresponding to the edge of the vacuum bubble, and in the medium flow direction, the bubble is 10 mm away from the vacuum bubble, and at least one temperature measuring hole 10 corresponds to the center position of the vacuum bubble.

[0070] For different heated plates 5, the positions and sizes of the vacuum bubble portions thereon are different. In view of this situation, in some optional embodiments, the insulating base 6 has a detachable positioning plate 11, and the positioning plate 11 can be configured as a polytetrafluoroethylene plate. The positioning plate 11 can specifically include a lower baffle 112 and an upper baffle 111, and the upper baffle 111 is embedded in the lower baffle 112. The overall shape of the lower baffle 112 is roughly a multi-diameter shaft body, and a matching groove is provided in the small diameter section of the lower baffle 112. The overall shape of the upper baffle 111 is similar to a circular cover body, and the upper baffle 111 is adapted to the shape of the matching groove so that the upper baffle 111 can be embedded in the matching groove, wherein the open end of the upper baffle 111 is located in the matching groove, and the closed end is located outside the matching groove, and the space in the upper baffle 111 serves as an installation cavity, and the installation cavity is adapted to the shape of the elastic sealing cavity 113 so that the outer wall of the elastic sealing cavity 113 can fit the cavity wall of the installation cavity, and the positioning plate 11 has There are temperature measuring holes 10, which means that some of the temperature measuring holes 10 among the multiple temperature measuring holes 10 are distributed on the positioning plate 11. Specifically, coaxial holes are respectively opened on the upper baffle 111 and the lower baffle 112, and every two coaxial holes on the upper baffle 111 and the lower baffle 112 serve as temperature measuring holes 10. The distribution forms of the temperature measuring holes 10 on different positioning plates 11 are different. According to the difference in the position and size of the vacuum bubble, the size and position of the temperature measuring holes 10 on the positioning plate 11 are different, which means that according to the position and size of the vacuum bubble, different positioning plates 11 can be replaced to facilitate the thermocouple to measure the heated plate 5; wherein the positioning plate 11 corresponds to the position of the vacuum bubble; in actual implementation, the specific shape of the positioning plate 11 may not be limited, and it may be constructed as a cylinder to adapt to the detection range around the vacuum bubble. In other embodiments, the positioning plate 11 may also be constructed as a prism, a hemispherical or other special-shaped shapes. The positioning plate 11 can also be removed, and the bubble position on the heated plate 5 is exposed, which is convenient for measuring the wall temperature field by an infrared thermometer.

[0071] See also Figure 5It can be understood that the projection area of ​​the positioning plate 11 in the normal direction of the heated plate 5 may be much larger than the vacuum bubble portion. At this time, temperature measuring holes 10 can also be set on the positioning plate 11 at positions corresponding to the surroundings of the vacuum bubble portion. These temperature measuring holes 10 correspond one-to-one to the temperature measuring holes 10 on the insulating base 6 and are coaxially arranged.

[0072] In some optional embodiments, the heat transfer simulation experimental device further includes a pressure measuring pipe 13, and the pressure measuring pipe 13 is connected to the narrow slit channel 7. In actual implementation, the pressure measuring pipe 13 passes through the insulation base 6 and is connected to the narrow slit channel 7. The number of the pressure measuring pipes 13 can be configured as two. In the flow direction of the medium, the two pressure measuring pipes 13 are respectively located on both sides of the vacuum bubble. Preferably, the two pressure measuring pipes 13 are respectively arranged close to the medium inlet 1 and the medium outlet 2. Through the arrangement of the pressure measuring pipe 13, the medium pressure in the narrow slit channel 7 can be measured, and the change characteristics of the medium pressure on both sides of the vacuum bubble can be obtained, which is conducive to the study of the influence of the vacuum bubble on the medium pressure under the heat generation state.

[0073] In some optional embodiments, the medium inlet 1 and / or the medium outlet 2 are provided with a temperature measuring pipe 12. In actual implementation, the temperature measuring pipe 12 can be provided on both the medium inlet 1 and the medium outlet 2. The temperature measuring pipe 12 can be conveniently provided to measure / monitor the medium temperature before the medium enters the narrow slit channel 7 and after the medium flows out of the narrow slit channel 7, which can bring convenience to the measurement process and facilitate the acquisition of the dynamic change characteristics of the medium temperature under long-term operation.

[0074] In some optional embodiments, the heat transfer simulation experimental device also includes a first pressure block 9 and a second pressure block 3 arranged at intervals, and the first pressure block 9 is connected to the second pressure block 3, wherein the first pressure block 9 abuts against the base, and the second pressure block 3 abuts against the cover body 4.

[0075] In the embodiment of the present application, by setting the first pressure-bearing block 9 and the second pressure-bearing block 3, the cover body 4 and the insulating base 6 can be pressed together, so as to ensure the stability of the sealing performance between the cover body 4 and the insulating base 6. The first pressure-bearing block 9 and the second pressure-bearing block 3 can be constructed as a rectangular parallelepiped, the first pressure-bearing block 9 can form a cover on the insulating base 6, the second pressure-bearing block 3 can form a cover on the cover body 4, and the first pressure-bearing block 9 and the second pressure-bearing block 3 can be fastened and connected by bolts. Among them, the temperature measuring pipe 12, the conductive part 8, the pressure measuring pipe 13, the medium inlet 1, the medium outlet 2 and the positioning plate 11 can all pass through the first pressure-bearing block 9 and the insulating base 6 in sequence to communicate with the narrow slit channel 7 or connect with the heated plate 5; when the cover body 4 has a light transmittance of not less than 98%, an observation window can be opened on the second pressure-bearing block 3, and in the normal direction of the plate surface of the heated plate 5, the vacuum bubble portion is located within the range covered by the observation window.

[0076] Among them, Figure 5 As shown, when the first pressure block 9 and the second pressure block 3 are set, the positioning plate 11 can be connected to the first pressure block 9 by bolts, so that there is no need to set a connecting structure corresponding to the positioning plate 11 on the insulating base 6. When installing the positioning plate 11, it is only necessary to perform relative positioning of the temperature measuring hole 10 and the vacuum bubble portion. The insulating base 6 does not participate in connecting the positioning plates, and the risk of structural damage to the insulating base 6 is greatly reduced, thereby ensuring that it has long-term stable thermal insulation and / or insulation performance.

[0077] In some optional embodiments, see Figure 7 The heated plate includes a blister plate 51, a heating plate 52 and an insulating layer 53; the blister plate 51 is formed with a groove through a casting process; the heating plate 52 and the blister plate 51 are arranged in parallel and spaced apart; the insulating layer 53 is located between the blister plate 51 and the heating plate 52, the insulating layer 53 is connected to the heating plate 52, and the insulating layer 53 is connected to the blister plate 51 through vacuum diffusion welding to enclose a vacuum bubble portion with the blister plate 51.

[0078] When the heated plate provided in the present application is used in an experimental device for simulating the heat transfer characteristics under the condition of bubbling on the surface of a diffuse fuel element, since the heating plate 52 relies on power to generate heat to simulate the heating of the diffuse fuel element, through the setting of the insulating layer 53, the current only passes through the heating plate 52 and does not pass through the bubbling plate 51, thereby truly simulating the distribution of heat sources in the prototype fuel element. It can avoid the situation where the self-heating of the bubbling plate 51 affects the temperature field near the vacuum bubble portion, that is, reduces the influencing factors of the temperature field near the vacuum bubble portion, facilitates subsequent theoretical analysis, and ensures the accuracy and credibility of the experimental results; and the insulating layer 53 is connected to the bubbling plate 51 by vacuum diffusion welding, and the connecting part has the characteristic of high temperature resistance, which is suitable for the bubbling temperature environment on the surface of the diffuse fuel element.

[0079] In actual implementation, the bubble plate 51 is configured as an Inconel625 plate, so that the thermal conductivity of the bubble plate 51 can be close to the parameters of the zirconium alloy cladding in the dispersed fuel element, and the thickness of the bubble plate 51 is configured to be no more than 1 / 10 of the thickness of the heating plate 52; the portion of the heating plate 52 used for conduction is configured as an S32168 plate to ensure better resistance to intergranular corrosion and high temperature strength, wherein the heating plate 52 as a whole can be configured as an S32168 plate; the insulating layer 53 can be formed by coating an aluminum nitride ceramic layer on the surface of the heating plate 52 using a PVD process, and the insulating layer 53 can be formed by coating an aluminum nitride ceramic layer on the surface of the heating plate 52 using a PVD process. The thickness of layer 53 is 30 to 50 μm to meet the requirement of not exceeding 1 / 10 of the thickness of the blister plate 51, so as to achieve effective insulation under the operating conditions of the maximum voltage of 50V in the experiment; the resistivity of the blister plate is much higher than that of the heating plate. In this way, if cracks appear in the insulating layer 53 during the diffusion welding process or during use, the heat generated by the blister plate 51 will not exceed 5% of the total heat generated by electrical conduction. The heat generated by the blister plate 51 affects the temperature field of the vacuum bubble part within an acceptable range, so that the experimental device has a certain ability to resist abnormalities, thereby ensuring the success rate of the experiment.

[0080] In summary, the heat transfer simulation experimental device provided in the embodiment of the present application can simulate the gap thermal resistance of the bubble area of ​​the diffuse fuel element, the cooling boundary shape of the narrow channel 7 and its heat transfer conditions; it is conducive to the measurement of experimental data such as the wall temperature near the vacuum bubble part, the fluid temperature field and velocity field in the narrow channel 7, and the visualization measurement of the boiling two-phase flow type in the narrow channel 7, so as to obtain the flow heat transfer characteristics near the vacuum bubble part, and then provide a reference basis for the actual study of the heat transfer characteristics of the diffuse fuel element in the bubble state.

[0081] The above specific embodiments illustrate the implementation methods of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation methods. On the contrary, the purpose of introducing the application in conjunction with the implementation methods is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide an in-depth understanding of the present application, the above description contains many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0082] It should be noted that in this specification, similar numbers and letters represent similar items in the above drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of this application, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A long electric heating plate insulation structure, characterized in that: include: A heat-insulating base (6), wherein the heat-insulating base (6) is configured as a ceramic resin plate, and a sink groove is provided on one plate surface of the heat-insulating base (6); A heat receiving plate (5), the heat receiving plate (5) being arranged in the sink trough so that the plate surface of the heat receiving plate (5) is flush with the plate surface of the heat insulating base (6), and a microporous alumina ceramic layer (15) nano-processed with an active coupling agent is arranged on the surface of the heat receiving plate (5) corresponding to the wall and bottom of the sink trough; An adhesive layer (14), wherein the adhesive layer (14) is disposed between the heated plate (5) and the insulating base (6) under a high-temperature vacuum pressure environment.

2. The long electric heating plate insulation structure according to claim 1 is characterized in that: The thickness of the microporous alumina ceramic layer (15) is configured to be 10 to 50 μm.

3. The long electric heating plate insulation structure according to claim 1 or 2, characterized in that: The aspect ratio of the micropores in the microporous alumina ceramic layer (15) is configured to be in the micrometer level.

4. The long electric heating plate insulation structure according to claim 1 is characterized in that: The groove wall and the groove bottom of the sink are configured as laser activated surfaces.

5. A heat transfer simulation experimental device for simulating the bubbling condition on the surface of a dispersed fuel element, characterized in that: include: The long electric heating plate insulation structure according to any one of claims 1 to 4, wherein the plate surface of the heating plate (5) facing away from the insulation base (6) has a vacuum bubble portion, an elastic sealing cavity (113) is provided in the insulation base (6), and the elastic sealing cavity (113) is filled with insulation powder (114), and a temperature measuring hole (10) corresponding to the position of the vacuum bubble portion is also provided on the insulation base (6), so that the thermocouple can pierce the elastic sealing cavity (113) through the temperature measuring hole (10) and contact the heating plate (5); A cover body (4), the cover body (4) having a flow slot, the cover body (4) being connected to the heat-insulating base (6) so that the heat-insulating base (6) seals the flow slot to form a narrow slit channel (7), and the heated plate (5) is located in the narrow slit channel (7); A medium introduction member (1), the medium introduction member (1) being in communication with one end of the narrow slit channel (7); A medium outlet (2), the medium outlet (2) being in communication with the other end of the narrow slit channel (7); Conductive members (8), two of the conductive members (8) are respectively connected to two ends of the heated plate (5), and the vacuum bubble portion is located between the two conductive members (8).

6. The heat transfer simulation experimental device according to claim 5, characterized in that: The cover body (4) is sealedly connected to the thermal insulation base (6) via a static sealing ring, wherein the static sealing ring is arranged around the flow groove.

7. The heat transfer simulation experimental device according to claim 5, characterized in that: The light transmittance of the cover body (4) is configured to be no less than 98%.

8. The heat transfer simulation experimental device according to claim 7, characterized in that: The cover body (4) is configured as optical quartz glass.

9. The heat transfer simulation experimental device according to claim 5, characterized in that: The conductive member (8) is connected to the heated plate (5) by silver brazing.

10. The heat transfer simulation experimental device according to claim 5, characterized in that: The number of the temperature measuring holes (10) is configured to be multiple, and in the normal viewing angle of the surface of the heated plate (5), the distance between the multiple temperature measuring holes (10) and the vacuum bubble portion is no more than 10 mm.

11. The heat transfer simulation experimental device according to claim 10, characterized in that: At least one temperature measuring hole (10) corresponds to the central position of the vacuum bubble portion.

12. The heat transfer simulation experimental device according to claim 5, characterized in that: The insulating base (6) has a detachable positioning plate (11), wherein the positioning plate (11) includes a lower baffle (112) and an upper baffle (111) embedded in the lower baffle (112), and an installation cavity suitable for accommodating the elastic sealing cavity (113) is formed between the upper baffle (111) and the lower baffle (112), and the temperature measuring hole (10) is located on the positioning plate (11); wherein the positioning plate (11) corresponds to the position of the vacuum bubble portion.

13. The heat transfer simulation experimental device according to claim 5, characterized in that: It also comprises a pressure measuring pipe (13), wherein the pressure measuring pipe (13) is in communication with the narrow slit channel (7).

14. The heat transfer simulation experimental device according to claim 5, characterized in that: The medium inlet (1) and / or the medium outlet (2) are provided with a temperature measuring pipe (12).

15. The heat transfer simulation experimental device according to claim 5 or 12, characterized in that: It also comprises a first pressure-bearing block (9) and a second pressure-bearing block (3) arranged at intervals, wherein the first pressure-bearing block (9) is connected to the second pressure-bearing block (3), wherein the first pressure-bearing block (9) abuts against the base, and the second pressure-bearing block (3) abuts against the cover body (4).

16. The heat transfer simulation experimental device according to claim 5, characterized in that: The heated plate (5) comprises: A blister plate (51), wherein the blister plate (51) is formed with a groove through a casting process; A heating plate (52), the heating plate (52) and the bubbling plate (51) are arranged in parallel and at intervals; An insulating layer (53), the insulating layer (53) is located between the blister plate (51) and the heating plate (52), the insulating layer (53) is connected to the heating plate (52), and the insulating layer (53) is connected to the blister plate (51) by vacuum diffusion welding so as to enclose a vacuum bubble portion with the groove on the blister plate (51).

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