Design method, test system and test method of supercritical carbon dioxide heat exchanger

Abstract

The present invention discloses a supercritical carbon dioxide heat exchanger and a design method, a test system and a test method, which belong to the technical field of heat exchange equipment. In order to solve the problem of low existing heat exchange efficiency, the supercritical carbon dioxide heat exchanger (1) comprises a heat exchange core (11), a head portion (12) and a connecting pipe portion (13), and the heat exchange core (11) contains a microchannel (111). The supercritical carbon dioxide heat exchanger uses the close-packed idea to arrange a large number of microchannels in a "J" shape, which has the characteristics of increasing length and reducing width. The supercritical carbon dioxide heat exchanger and the design method provide design ideas for microchannel supercritical carbon dioxide heat exchangers in different application scenarios; the test system and the test method use modularization ideas and multi-physics coupling ideas to integrate a variety of performance test methods, opening up problem-solving ideas for improving the performance test efficiency of supercritical carbon dioxide heat exchangers.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange equipment, and in particular to a design method of a supercritical carbon dioxide heat exchanger, a multi-physics coupling test system of the supercritical carbon dioxide heat exchanger, and a test method of the multi-physics coupling test system. Background Art

[0002] Heat exchangers are general process equipment for allocating energy between different logistics and completing heat transfer. They are widely used in a large number of industries such as power generation, chemical industry, power, metallurgy, etc., especially in power circulation systems with supercritical carbon dioxide as the working fluid. Heat exchangers play an important role in transferring and allocating energy between working fluids.

[0003] With the continuous improvement of science and technology, people pay more and more attention to the special application scenarios of power systems involved in nuclear power plants, thermal power plants, and aircraft engines. Reducing the size of equipment, improving efficiency, reducing equipment manufacturing and operating costs, and natural resource consumption are one of the future development directions of heat exchangers. At present, the heat exchangers used in conventional industrial fields mainly include shell and tube heat exchangers, sleeve and tube heat exchangers, plate heat exchangers, plate-fin heat exchangers, etc. They cannot simultaneously meet the requirements of large heat transfer specific surface area, high welding strength, and small size. In recent years, with the improvement of industrial manufacturing level, microchannel heat exchangers with high-precision chemical etching and vacuum diffusion welding as the core process have gradually entered the application stage. Their microchannels are small in size, highly compact, and the welding method has no welding slag. The strength of the joints is close to the strength of the parent material, which has obvious advantages.

[0004] However, the typical structure of this type of heat exchanger is unidirectional flow in the microchannel. The flow length on the heat exchange plate of the same size is limited, and the flow width is too large, resulting in a low flow rate, which makes the design of this type of heat exchanger have the problem of low heat exchange efficiency. At the same time, the performance tests of this type of heat exchanger need to be carried out separately and independently. For example, the mechanical properties are first obtained through water pressure testing, and then the heat transfer performance is obtained through thermal hydraulic testing, and finally the anti-corrosion performance is obtained through long-term testing. Summary of the invention

[0005] In order to solve the problem of low heat exchange efficiency of existing supercritical carbon dioxide heat exchangers, embodiments of the present invention provide a supercritical carbon dioxide heat exchanger and a design method thereof, a multi-physics coupling test system and a test method. The supercritical carbon dioxide heat exchanger utilizes the idea of ​​close packing to arrange a large number of microchannels in a "J-shape", which has the characteristics of increasing length and reducing width. The supercritical carbon dioxide heat exchanger and the design method provide design ideas for microchannel supercritical carbon dioxide heat exchangers for different application scenarios; the multi-physics coupling test system and the test method utilize modularization ideas and multi-physics coupling ideas to integrate a variety of performance testing methods, thereby opening up problem-solving ideas for improving the performance testing efficiency of supercritical carbon dioxide heat exchangers.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A supercritical carbon dioxide heat exchanger comprises a heat exchange core, a head portion and a connecting pipe portion, wherein the heat exchange core contains microchannels, the microchannels include a plurality of first microchannels and a plurality of second microchannels, the head portion includes a first inlet head, a first outlet head, a second inlet head and a second outlet head, and the connecting pipe portion includes a first inlet connecting pipe, a first outlet connecting pipe, a second inlet connecting pipe and a second outlet connecting pipe; the first inlet connecting pipe, the first inlet head, the first microchannel, the first outlet head and the first outlet connecting pipe are connected in sequence, and the second inlet connecting pipe, the second inlet head, the second microchannel, the second outlet head and the second outlet connecting pipe are connected in sequence.

[0008] The heat exchange core contains a plurality of stacked heat exchange plates, and the heat exchange plates are welded, and the welding is diffusion welding, brazing or fusion welding.

[0009] The heat exchange core and the end portion are welded, and the end portion and the connecting pipe are welded, and the welding is argon arc welding, brazing or ion welding.

[0010] The heat exchange core contains a plurality of stacked heat exchange plates, the heat exchange plates include a primary side heat exchange plate and a secondary side heat exchange plate, the first microchannel is located in the primary side heat exchange plate, and the second microchannel is located in the secondary side heat exchange plate; the stacking arrangement of the heat exchange plates in the heat exchange core is: one primary side heat exchange plate and one secondary side heat exchange plate are alternately arranged, or one primary side heat exchange plate and two secondary side heat exchange plates are alternately arranged, or two primary side heat exchange plates and one secondary side heat exchange plate are alternately arranged.

[0011] The heat exchange core contains a plurality of stacked heat exchange plates, the thickness of the heat exchange plates is 1mm-5mm, and the cross-sectional size of the microchannel is 1mm-10mm.

[0012] The microchannels are linear or folded, rib walls are arranged between the microchannels, and the width of the rib walls is 0.5 mm-10 mm.

[0013] The inner surface of the microchannel is a rough surface, the inner surface of the microchannel is connected with attachments, or the inner surface of the microchannel is connected with a vortex generator.

[0014] The microchannels are arranged in a "J" shape for rotational flow, and the number of times the microchannel turns 180° plus one is the rotation number M, and the microchannels are divided into N groups of "J" shaped microchannels parallel to each other, where M and N are both natural numbers. If M is an odd number, the inlet and outlet of the microchannel are on the same side of the supercritical carbon dioxide heat exchanger, and if M is an even number, the inlet and outlet of the microchannel are on the opposite sides of the supercritical carbon dioxide heat exchanger.

[0015] A fillet transition is provided at the turning point of the microchannel.

[0016] The microchannel is in a shape of a figure '几', and rib walls are provided between the microchannels. Transverse communication holes can be provided in the rib walls, and the shapes include circular, semi-circular or square.

[0017] The microchannel further includes a third microchannel, the sealing head portion further includes a third inlet sealing head and a third outlet sealing head, and the connecting pipe portion further includes a third inlet connecting pipe and a third outlet connecting pipe; the third inlet connecting pipe, the third inlet sealing head, the third microchannel, the third outlet sealing head and the third outlet connecting pipe are connected in sequence.

[0018] The length and width of the heat exchange plate are L x and L y , respectively. The heat exchange plate contains a blank area and a heat exchange area, where the width of the blank area is p, and the length and width of the heat exchange area are and , respectively. The microchannel and the rib wall are both located in the heat exchange area.

[0019] The flow width W and the flow length S of the microchannel at the inlet or outlet position are respectively: and .

[0020] On the premise that the microchannel is semi-circular, the single-plate flow area A h and the single-plate heat exchange area S h of the supercritical carbon dioxide heat exchanger are respectively: and .

[0021] A design method of the above-mentioned supercritical carbon dioxide heat exchanger, the design method sequentially includes the following steps:

[0022] Step 1a: Obtain the input parameters of the working fluids on both sides;

[0023] Step 2a: Initially select the size L x , L y of the heat exchange plate and the width p of the blank area according to the process limitations, and calculate the size l x and l y of the supercritical carbon dioxide heat exchanger;

[0024] Step 3a: Select the width d of the microchannel of the working fluids on both sides and the width t of the rib wall according to the processing limitations of the microchannel and the mechanical strength criterion;

[0025] Step 4a: Initially set the rotation number M = 1 and the number of microchannel groups N = 1 of the microchannels of the working fluids on both sides;

[0026] Step 5a: According to the values of M and N, the l x and ly As a result, W is estimated by looking up the table, and then based on the formula Calculate S, and finally calculate the single board flow area A based on W and S h and heat exchange area S h ;

[0027] Step 6a, carry out thermal hydraulic design calculations, and adjust M and N according to whether the results meet the design input, until the requirements of flow and heat transfer characteristics are met at the same time;

[0028] Step 7a: Re-calculate W and S, carry out thermal hydraulic verification calculations, and compare again whether the requirements of flow and heat transfer characteristics are met. If not, return to the previous step until the design requirements are met, and then proceed to the next step;

[0029] Step 8a: Draw the construction drawings of the heat exchange plates on both sides.

[0030] A multi-physics coupling test system for a supercritical carbon dioxide heat exchanger includes a plurality of functional modules, wherein the plurality of functional modules are:

[0031] The module to be tested is used to install the supercritical carbon dioxide heat exchanger to be tested;

[0032] A cooling module, used for cooling the test working fluid flowing out of the supercritical carbon dioxide heat exchanger to be tested;

[0033] A heating module, used to preheat the test working fluid to the designed temperature value to reach the inlet of the supercritical carbon dioxide heat exchanger to be tested;

[0034] A modification module, used for adding different types of substances into the multi-physics coupling test system to achieve working fluid modification;

[0035] A driving module, used to drive the test working fluid to operate;

[0036] A pressure module, used to increase the pressure of the working fluid in the multi-physics coupling test system;

[0037] The charging and discharging module is used to charge or discharge the working fluid into the multi-physics coupling test system.

[0038] The module shell of each of the functional modules is a container or a pressure vessel, the module shell of each of the functional modules is the same, and each of the functional modules includes an interface flange.

[0039] The multi-physics coupling test system can test a variety of different supercritical carbon dioxide heat exchangers to be tested, and the heat exchange working fluids that can be tested by the multi-physics coupling test system include carbon dioxide, water and helium.

[0040] The cooler in the cooling module is a serpentine tube heat exchanger or a shell-and-tube heat exchanger, and the cooling liquid used in the cooling module is water or oil.

[0041] The driving module contains a driving pump, which is a centrifugal pump or a magnetic pump.

[0042] The charging and discharging module contains a regulator, and the regulator uses nitrogen or helium as the pressure-stabilizing gas.

[0043] A variety of measuring components are installed on the supercritical carbon dioxide heat exchanger to be tested, and the various measuring components include a temperature measuring component, a pressure measuring component, a strain measuring component and a corrosion measuring component.

[0044] The temperature measuring component includes a temperature measuring joint, a first cap nut, a first perforated copper pad, a temperature measuring instrument, a fastening nut, a rubber pad and a temperature measuring screw hole. The temperature measuring instrument can be fixed by adjusting the relative position of the temperature measuring joint and the first cap nut and adjusting the pressure state of the first perforated copper pad.

[0045] The pressure measuring assembly includes a pressure measuring joint, a second cap nut, a second perforated copper pad, a pressure measuring tube and a pressure measuring screw hole. The pressure measuring tube can be fixed by adjusting the relative position of the pressure measuring joint and the second cap nut to adjust the pressure state of the second perforated copper pad.

[0046] The strain measuring component comprises a strain measuring joint, a strain column, a strain measuring screw hole and a measuring wire, and measures the strain characteristics of the surface of the supercritical carbon dioxide heat exchanger to be measured through the tension or compression state of the strain column.

[0047] The corrosion detection component includes a corrosion detection joint, a third cap nut, a blind copper pad and a collecting side hole. By adjusting the relative position of the corrosion detection joint and the third cap nut and adjusting the pressure state of the blind copper pad, it is possible to adjust whether the testing fluid flows out of the corrosion detection component to detect the working fluid composition.

[0048] A test method for the multi-physics coupling test system comprises the following steps:

[0049] Step 1b, building the multi-physics coupling test system according to the design parameter range of the supercritical carbon dioxide heat exchanger to be tested;

[0050] Step 2b, charging a quantitative operating medium and a pressure-stabilizing gas into the multi-physics coupling test system through a charging and discharging module, starting and adjusting a cooling module and a heating module until the inlet parameters of the supercritical carbon dioxide heat exchanger to be tested meet the design requirements;

[0051] Step 3b, collecting different parameters on the supercritical carbon dioxide heat exchanger to be tested through the multiple measurement components, and calculating and obtaining the multi-physical coupling characteristics of the supercritical carbon dioxide heat exchanger to be tested;

[0052] Step 4b: Adjust the parameters to the next measurement point and repeat step 3b above.

[0053] The beneficial effects of the present invention are: the efficient and compact supercritical carbon dioxide heat exchanger proposed in the present invention increases the flow length of the microchannel by using a "J-shaped" arrangement, and can flexibly change the flow length and width of the microchannel during the design process according to project requirements, thereby improving the flow and heat exchange capacity of the working fluid; the heat exchanger test system currently used mainly adopts the idea of ​​a dedicated system to test a single performance, and the multi-physics coupling test system proposed in the present invention can simultaneously test the flow, heat transfer, strength and anti-corrosion characteristics of the supercritical carbon dioxide heat exchanger, has strong applicability, can be widely used in thermal management scenarios, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0055] Figure 1 Schematic diagram of the supercritical carbon dioxide heat exchanger of the present invention.

[0056] Figure 2 Schematic diagram of the first type of primary side heat exchange plate.

[0057] Figure 3 Schematic diagram of the second type of primary side heat exchange plate.

[0058] Figure 4 Schematic diagram of the first type of secondary side heat exchange plate.

[0059] Figure 5 for Figure 4 Enlarged schematic diagram of the middle right part.

[0060] Figure 6 for Figure 5 Schematic diagram of the structure of the first type of microchannel in part A.

[0061] Figure 7 for Figure 5 Schematic diagram of the structure of the second microchannel in part A.

[0062] Figure 8 for Figure 5 Schematic diagram of the structure of the third microchannel in part A.

[0063] Fig. 9 Flowchart of the design method for a supercritical carbon dioxide heat exchanger.

[0064] Fig.10 Schematic diagram of the circulation width under different M and N values.

[0065] Fig.11 Layout diagram of the multi-physics coupling test system.

[0066] Fig.12 This is the structural diagram of the temperature measurement component.

[0067] Fig.13 This is a schematic diagram of the working status of the temperature measurement component.

[0068] Fig.14 This is a structural diagram of the pressure measuring component.

[0069] Fig.15 This is a schematic diagram of the working status of the pressure measuring component.

[0070] Fig.16 Schematic diagram of the top view of the strain measurement component.

[0071] Fig.17 This is the structural diagram of the strain measurement component.

[0072] Fig.18 Structural diagram of the corrosion test component.

[0073] Fig.19 Schematic diagram of the working status of the corrosion detection component.

[0074] Fig. 20 Flowchart of the test method for the multi-physics coupled test system.

[0075] Description of reference numerals:

[0076] 1. Supercritical carbon dioxide heat exchanger; 2. Multi-physics coupling test system; 4. Temperature measurement component; 5. Pressure measurement component; 6. Strain measurement component; 7. Corrosion measurement component;

[0077] 11. Heat exchange core; 12. End portion; 13. Pipe connection portion;

[0078] 111, microchannel; 112, heat exchange plate; 113, cover plate; 114, blank area; 115, heat exchange area; 116, rib wall;

[0079] 1111, first microchannel; 1112, second microchannel;

[0080] 1121, primary side heat exchange plate; 1122, secondary side heat exchange plate;

[0081] 121, first inlet end cap; 122, first outlet end cap; 123, second inlet end cap; 124, second outlet end cap;

[0082] 131, first inlet pipe; 132, first outlet pipe; 133, second inlet pipe; 134, second outlet pipe;

[0083] 21. Module to be tested; 22. Cooling module; 23. Heating module; 24. Modification module; 25. Driving module; 26. Pressurization module; 27. Charging and exhausting module; 28. Module housing; 29. ​​Interface flange;

[0084] 211, supercritical carbon dioxide heat exchanger to be tested; 212, sports table; 221, cooler; 231, preheater; 241, mixing tank; 242, modification interface; 251, driving pump; 252, regulating valve; 261, booster pump; 262, booster interface; 271, regulator; 272, gas bottle;

[0085] 41. Temperature measuring joint; 42. First cap nut; 43. First perforated copper pad; 44. Temperature measuring instrument; 45. Fastening nut; 46. Rubber pad; 47. Temperature measuring screw hole;

[0086] 51. pressure measuring joint; 52. second cap nut; 53. second copper washer with holes; 54. pressure measuring tube; 55. pressure measuring screw hole;

[0087] 61. Strain measuring joint; 62. Strain column; 63. Strain measuring screw hole; 64. Measuring wire;

[0088] 71. Corrosion test joint; 72. Third cap nut; 73. Blind copper pad; 74. Collecting side hole. DETAILED DESCRIPTION

[0089] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0090] A supercritical carbon dioxide heat exchanger, the supercritical carbon dioxide heat exchanger 1 comprising a heat exchange core 11, a head portion 12 and a pipe portion 13, the heat exchange core 11 contains a plurality of microchannels 111, the plurality of microchannels 111 include a plurality of first microchannels 1111 and a plurality of second microchannels 1112, the head portion 12 includes a first inlet head 121, a first outlet head 122, a second inlet head 123 and a second outlet head 124, the pipe portion 13 includes a first inlet pipe 131, a first outlet pipe 132, a second inlet pipe 133 and a second outlet pipe 134; the first inlet pipe 131, the first inlet head 121, the first microchannel 1111, the first outlet head 122 and the first outlet pipe 132 are connected in sequence, and the second inlet pipe 133, the second inlet head 123, the second microchannel 1112, the second outlet head 124 and the second outlet pipe 134 are connected in sequence.

[0091] like Figure 1As shown, the supercritical carbon dioxide heat exchanger 1 includes a heat exchange core 11, a head portion 12 and a pipe portion 13, wherein the heat exchange core 11 is used to complete the flow heat exchange process between multiple working fluids, and the head portion 12 and the pipe portion 13 are used to guide and constrain multiple working fluids to independently enter and exit the supercritical carbon dioxide heat exchanger. For example, the endothermic working fluid g flows through the first inlet pipe 131, the first inlet head 121, the first microchannel 1111, the first outlet head 122 and the first outlet pipe 132 in sequence, and the exothermic working fluid q flows through the second inlet pipe 133, the second inlet head 123, the second microchannel 1112, the second outlet head 124 and the second outlet pipe 134 in sequence, and the endothermic working fluid g absorbs heat in the heat exchange core 11, and the exothermic working fluid q absorbs heat and releases heat in the heat exchange core 11.

[0092] The heat exchange core 11 is composed of a heat exchange plate 112 and a cover plate 113. A plurality of heat exchange plates 112 are stacked. The heat exchange plates 112 include a primary side heat exchange plate 1121 and a secondary side heat exchange plate 1122. That is, the heat exchange core 11 is composed of three types of plates: the primary side heat exchange plate 1121, the secondary side heat exchange plate 1122 and the cover plate 113. The three types of plates are all metal mirror plates, and their lengths and widths are equal, but their thicknesses are not necessarily equal. Generally, the cover plate 113 is thicker than the other two types of plates.

[0093] The material of the supercritical carbon dioxide heat exchanger 1 includes metal materials such as stainless steel, carbon steel, titanium alloy, or non-metallic materials such as ceramics. The connection between the heat exchange plates 112 of the supercritical carbon dioxide heat exchanger 1 can be made using methods that can weld over a large area, such as diffusion welding, brazing, or fusion welding. The connection between the heat exchange core 11 and the head 12 can be made using various electric welding methods, such as argon arc welding, brazing, and ion welding. In addition to a semicircular shape, the head 12 of the supercritical carbon dioxide heat exchanger 1 can also be in a variety of shapes, including circular, rectangular, square, etc., and the shape of the connecting pipe must adopt a corresponding shape, as long as the wall thickness of the connecting pipe meets the pressure requirements.

[0094] The surface of the cover plate 113 is not subjected to additional processing. Both the primary side heat exchange plate 1121 and the secondary side heat exchange plate 1122 can be divided into two areas: a blank area 114 and a heat exchange area 115. The blank area 114 is an unprocessed area. A large number of semicircular grooves (i.e., microchannels 111) are processed in the heat exchange area 115 by chemical etching, mechanical cutting and other means. The microchannels 111 are only located in the heat exchange area 115 and not in the blank area 114. The microchannels 111 of the two heat exchange plates (the primary side heat exchange plate 1121 and the secondary side heat exchange plate 1122) may not be the same. The unprocessed metal wall between the microchannels 111 is the rib wall 116. The size of the microchannels 111 and the width of the rib wall 116 of the two plates (the primary side heat exchange plate 1121 and the secondary side heat exchange plate 1122) may not be the same.

[0095] The cover plate 113 should be placed on the top and bottom layers of the heat exchange core 11, and the two types of heat exchange plates in the middle (primary heat exchange plate 1121 and secondary heat exchange plate 1122) should be stacked periodically according to a certain order, for example, the primary heat exchange plate 1121 and the secondary heat exchange plate 1122 are stacked alternately one layer at a time. Finally, the stacked multiple plates are welded by vacuum diffusion welding or other welding methods to form a heat exchange core 11. At this time, the inlet and outlet end faces formed by the aggregation of a large number of microchannels 111 will appear on the four sides of the heat exchange core 11, and the fluid enters and exits from here.

[0096] When the design requires a larger heat exchange power, multiple heat exchange cores 11 can be further stacked into one body, and adjacent heat exchange cores 11 can be fixed together by fusion welding, electron beam welding or other connection methods.

[0097] The end cap 12 is a semi-cylindrical metal shell obtained by rolling or material reduction processing of forgings. The size of the end cap 12 can just cover the inlet and outlet end faces of the corresponding side working fluid on the heat exchange core 11. The connecting pipe 13 is a metal seamless pipe, with a hole opened in the center of the arc surface of the end cap 12, the size of which is the same as the outer diameter of the connecting pipe 13, the connecting pipe 13 can be inserted into it and connected as a whole by fusion welding, electron beam welding, etc., and finally welded as a whole to the inlet and outlet end faces of the heat exchange core to realize the independent entry and exit of each fluid in the supercritical carbon dioxide heat exchanger. Generally, the inlet and outlet end caps 12 and connecting pipes 13 of the working fluid on the same side are arranged on a set of opposite surfaces of the heat exchange core 11.

[0098] like Figures 2 to 8 As shown in FIG. 1 , they are respectively structural diagrams of the primary side heat exchange plate 1121 and the secondary side heat exchange plate 1122 in the supercritical carbon dioxide heat exchanger of the present invention. The two heat exchange plates (primary side heat exchange plate 1121 and secondary side heat exchange plate 1122) are substantially the same except for the end faces of the heat exchange core 11 where the inlet and outlet are located. Figure 2 Take this as an example for detailed introduction.

[0099] Figure 2 The microchannel 111 arrangement structure on the heat exchange plates 112 (primary side heat exchange plate 1121 and secondary side heat exchange plate 1122) of a general supercritical carbon dioxide heat exchanger is such that the working fluid enters from one end and flows directly to the other end, and finally flows out of the heat exchange core 11, which is a unidirectional flow; Figure 2 The structure shown is a "J-shaped" arrangement of the microchannel 111. After the working fluid enters the heat exchange zone, it turns repeatedly, which increases the flow length on the heat exchange plate 112. At the same time, the increase in the number of turns can effectively reduce the axial heat conduction problem of the fluid due to the long turning distance, which causes the direct heat conduction of the metal to be stronger than the convective heat transfer. Through a large number of small turns, the influence of the axial heat conduction problem on the performance deviation of the supercritical carbon dioxide heat exchanger is reduced.

[0100] The thickness of the heat exchange plate 112 may be about 1 mm to 5 mm, and the cross-sectional size (such as diameter) of the microchannel 111 may be in the range of 1 mm to 10 mm. Although the microchannel is arranged in a "J" shape according to the present invention, the flow shape in the length direction may include different flow shapes such as straight line, broken line, and airfoil (such as Figures 6 to 8 As shown in the figure, the width of the rib wall between each microchannel is in the range of 0.5mm-10mm. The surface flow heat transfer characteristics of the microchannel 111 can be changed by changing the roughness, adding attachments, adding vortex generators, etc., to improve the heat exchange effect.

[0101] The supercritical carbon dioxide heat exchanger 1 can be supported by I-beam brackets, modular profile racks or directly buried in the ground. The "J-shaped" microchannel of the microchannel heat exchange plate can use a rounded transition at the 90° turn to reduce flow resistance, and the rounded radius can be 0mm-10mm; the "J-shaped" microchannel of the microchannel heat exchange plate can add connecting holes at the lateral gap by drilling, etching, etc., to connect different microchannel groups, promote the exchange of fluids between microchannel organizations, and improve the uniformity of flow distribution.

[0102] The number of revolutions M of the microchannel heat exchange plate 112 may also be an even number. In this case, the working fluid on this side enters and exits the supercritical carbon dioxide heat exchanger on the same side, and needs to be multiplied by the correction factor φ in the heat exchange design calculation and the process of calculating the convective heat transfer coefficient h. This can reduce the volume occupied by the supercritical carbon dioxide heat exchanger and improve its compactness.

[0103] The number of types of flow heat exchange working fluids in the supercritical carbon dioxide heat exchanger is not limited to 2, and can be 3 or more. The corresponding number of types of microchannel heat exchange plates will increase to be equal to the number of working fluid types. At this time, the inlet and outlet heads of the working fluid can be arranged from both ends of the supercritical carbon dioxide heat exchanger to the center, and the working fluid flow distance at the two ends is the longest, and the opposite is true at the center.

[0104] For example, the microchannel 111 also includes a third microchannel, the head portion 12 also includes a third inlet head and a third outlet head, and the connecting pipe portion 13 also includes a third inlet connecting pipe and a third outlet connecting pipe; the third inlet connecting pipe, the third inlet head, the third microchannel, the third outlet head and the third outlet connecting pipe are connected in sequence.

[0105] Table 1 below defines the names, symbols and relationship between variables on the heat exchange plate 112. Figure 2 Take an example to explain in detail.

[0106] Depend on Figure 2It can be seen that, limited by the processing size of the heat exchange plate 112 (the primary side heat exchange plate 1121 and the secondary side heat exchange plate 1122) and the welding size of vacuum diffusion welding, the length and width of the heat exchange plate 112 are L x and L y Considering that the strength of vacuum diffusion welding must meet the design pressure of the working fluid, the width of the blank area 114 is p, so the length of the heat exchange area 115 is l x and width l y As follows:

[0107] Formula 1

[0108] Formula 2

[0109] In the heat exchange area 115, the width of a microchannel 111 is d. If its cross-sectional shape is semicircular, then the width of the microchannel is its diameter. According to engineering test experience, d is generally in the range of 1mm-10mm. The width of the metal rib wall 116 between adjacent microchannels 111 is t. According to the processing accuracy requirements, t is generally not less than 0.4mm.

[0110] In the heat exchange area 115, a large number of microchannels 111 are arranged in a "J" shape to rotate and flow. The number of times the working fluid makes a 180° turn on the heat exchange plate 112 plus one is defined as the number of rotations M (in this embodiment, M=9); a large number of microchannels 111 are divided into a number of groups parallel to each other and flow and exchange heat synchronously on the heat exchange plate. The microchannels 111 in each group are nested and extended in a "J" shape. The "J"-shaped microchannels 111 between the groups do not overlap with each other. The number of microchannel groups is defined as N (in this embodiment, N=2), the number of microchannels in a microchannel group is defined as n, and there are gaps between the microchannel groups to prevent fluid cross-flow. The lateral gap and the longitudinal gap of the microchannel 111 are defined as w respectively. x and w y , and stipulate that within the same microchannel group, the gap of the "J" bend is also w x . According to engineering design experience and processing technology, w x and w y Generally greater than t and less than (1 to 5) d.

[0111] In order to make the lengths of all microchannels 111 in a microchannel group equal, the inlet and outlet of the working fluid on the same side are required to be on the opposite side of the heat exchange plate, so M is an odd number and N is a natural number. It can be obtained that the width W0 of a microchannel group is calculated as follows:

[0112] Formula 3

[0113] The height H of a microchannel group can be calculated by l y、w y It can be obtained after other variables such as , N, etc. are known.

[0114] Further, the flow width W is defined as the width of the area where the microchannel 111 is located at the inlet or outlet position, and the flow length S is defined as the length of the microchannel 111, that is, the flow heat exchange distance of the working fluid in the supercritical carbon dioxide heat exchanger. According to the geometric relationship, it can be deduced that W and S are calculated as follows:

[0115] Formula 4

[0116] Formula 5

[0117] Furthermore, under the premise that the microchannel is semicircular, the single plate flow area A of the supercritical carbon dioxide heat exchanger h And the single plate heat exchange area S h Calculated as follows:

[0118] Formula 6

[0119] Formula 7

[0120] Now change the angle and recalculate the length and width of the heat exchange zone 115. The former is composed of the width of multiple microchannel groups and the lateral gaps of multiple microchannel groups. Therefore, the length l of the heat exchange zone is x Which is equal to:

[0121] Formula 8

[0122] Similarly, the width of the heat exchange zone is composed of the longitudinal gaps between multiple microchannel groups, so the width of the heat exchange zone l y Which is equal to:

[0123] Formula 9

[0124] The above calculation formula is shown in Table 1.

[0125]

[0126] The units of the above parameters are all mm. According to the design results of microchannel supercritical carbon dioxide heat exchangers in a large number of references, it is found that w x and w y Generally in the millimeter range, compared to l x and l y Generally, it is in the order of meters, so the former is a small amount of the latter. Then the present invention also proposes another method for approximate calculation of W and S, that is, ignoring w x and w y, then the entire heat exchange area is completely composed of N closely packed microchannel groups. Through the geometric relationship, we can get:

[0127] Formula 10

[0128] At the same time, since the area is constant, that is, , then we can get:

[0129] Formula 11

[0130] Observation A h and S h From the definition of N n is their independent variable. According to the definition of W and W0 in the above table, N can be obtained after processing. n expression and put it into A h and S h The definition of can be obtained:

[0131]

[0132] Formula 12

[0133]

[0134] Because A h and S h It is the core parameter of the design of the supercritical carbon dioxide heat exchanger and is a function of W and S, which means that W and S are also important parameters of the design of the supercritical carbon dioxide heat exchanger. Under the premise that the size of the heat exchange plate is determined, when M and N are determined, the ratio of the flow width to the heat exchange zone width W / l can be estimated. x , and then calculate the flow length and determine the flow parameters of the entire supercritical carbon dioxide heat exchanger microchannel. The following table shows the W / l under the commonly used M and N value combinations in industry. x The specific size of the Fig.10 As shown in the figure, different flow areas and heat exchange areas can be achieved by selecting different flow widths W, thereby achieving different designs. The flow widths under different M and N values ​​are shown in Table 2.

[0135]

[0136] In order to ensure the accuracy of the above estimation, the following conditions must be met:

[0137] Formula 13

[0138] Combine the following Fig. 9The design method of the high-efficiency and compact supercritical carbon dioxide heat exchanger of the present invention is further explained as follows:

[0139] Step 1a, obtaining the input parameters of the working fluids on both sides, including inlet and outlet temperatures, inlet pressure, mass flow rate and allowable pressure drop, etc., and calculating the flow heat transfer characteristics of the supercritical carbon dioxide heat exchanger, wherein the heat transfer characteristic is the heat transfer amount, which can be calculated based on the above parameters, and the flow characteristic is the allowable pressure drop;

[0140] Step 2a: According to the welding process limitations of this type of microchannel supercritical carbon dioxide heat exchanger, the size of the heat exchange core 11 is preliminarily selected, that is, the L of the heat exchange plate 112. x and L y And the width of the blank area p, based on which the size of the heat exchange area l can be calculated x and l y .

[0141] Step 3a: Preliminarily select the size d and rib wall width t of the microchannel of the supercritical carbon dioxide heat exchanger based on the microchannel processing technology limitations of this type of microchannel supercritical carbon dioxide heat exchanger and the mechanical strength criteria (such as national standards, ASME standards, etc.) for ensuring the integrity of the pressure boundary of the microchannel supercritical carbon dioxide heat exchanger under the inlet working pressure.

[0142] Step 4a: According to the structure proposed by the present invention, the degree of rotation M and the number of microchannel groups N are preliminarily selected and all are set to 1 without units.

[0143] Step 5a: Estimate W / l by the estimation method proposed by the present invention according to Formula 10, Formula 11 and Table 2. x and S / l y , and then estimate the single plate flow area A of the supercritical carbon dioxide heat exchanger according to formula 6 and formula 7 h And the single plate heat exchange area S h .

[0144] Step 6a: According to the structural parameters of the single heat exchanger plate, thermal hydraulic design calculation is carried out, that is, according to the flow area A of the single plate h And the single plate heat exchange area S h , set the number of heat exchange plates, obtain the flow area and heat exchange area of ​​the supercritical carbon dioxide heat exchanger, and calculate the flow velocity v of the working fluid on both sides based on the mass flow rate, calculate the turbulence degree of the working fluid on both sides, that is, the Reynolds number Re, based on the flow velocity v, calculate the Nusselt number Nu=f'(Re, P, T) and Fanning friction factor f=g'(Re) based on the public flow heat transfer relationship, and calculate h=Nu λ / d, calculate the heat transfer coefficient h, and finally according to Q=h A ΔT calculates the actual heat transfer Q, where A is the heat transfer area of ​​the supercritical carbon dioxide heat exchanger, and compares it with the heat transfer characteristics obtained by formula 1; according to ΔP=f S / d ρ v 2 / 2 calculates the pressure drop of the supercritical carbon dioxide heat exchanger, where f is the Fanning friction factor, S is the flow length, d is the microchannel size, ρ is the working fluid density, and v is the working fluid flow rate, and compares it with the flow characteristics obtained by formula 1. If all the flow and heat transfer characteristics of the working fluids on both sides meet the requirements, the design is completed. If not, the discussion is classified according to whether the heat transfer characteristics or flow characteristics are not satisfied. If it is the former, it means that W is too large and S is too small. If it is the latter, it means that S is too large and W is too small. Both M and N need to be adjusted to redesign the calculation.

[0145] Step 7a: After the design calculation is passed, a verification calculation needs to be carried out: According to the M and N set in the previous step and the process processing experience, select w x and w y The specific value of is taken, and W and S are recalculated accurately based on this. According to the number of heat exchanger plates set in the previous step, the flow area and heat exchange area of ​​the supercritical carbon dioxide heat exchanger are recalculated, and the structure of the supercritical carbon dioxide heat exchanger is adjusted considering parameters such as the design margin. Finally, thermal-hydraulic verification calculations are performed to ensure that the design still meets the design requirements.

[0146] Step 8a: Based on the above design results, draw the structural design drawings of the heat exchange plates and cover plates on both sides and send them to the manufacturer for processing.

[0147] Combine the following Fig.11 The composition principle and contents of a multi-physics (parameter) coupling test system for a supercritical carbon dioxide heat exchanger of the present invention are further explained. The multi-physics coupling test system for a supercritical carbon dioxide heat exchanger is only one but not the only embodiment of the present invention.

[0148] like Fig.11 As shown, the multi-physics coupling test system 2 can be mainly divided into seven (functional modules), namely, a test module 21, a cooling module 22, a heating module 23, a modification module 24, a driving module 25, a pressure module 26 and a charging and discharging module 27. Their uses are: measuring the supercritical carbon dioxide heat exchanger to be tested, cooling the operating working fluid, heating the operating working fluid, adjusting the operating working fluid composition, driving the operating working fluid, adjusting the operating working fluid pressure and stabilizing the system pressure.

[0149] The test module 21 will be used to provide a variety of high-efficiency and compact supercritical carbon dioxide heat exchanger test prototypes with different structures to measure the inlet and outlet thermal parameters of the supercritical carbon dioxide heat exchanger to be tested; the cooling module 22 will be used to cool the test working fluid flowing out of the supercritical carbon dioxide heat exchanger to be tested to maintain the normal operation of the system; the heating module 23 will be used to preheat the test working fluid to reach the inlet of the supercritical carbon dioxide heat exchanger to be tested at the designed temperature value, providing a wide parameter test range; the modification module 24 will be used to add different types of substances to the test system to achieve working fluid modification, complete performance tests of different working fluid physical properties or long-term corrosion tests; the driving module 25 will be used to drive the test working fluid to operate at a fixed flow rate to ensure the stable operation of the system; the pressure module 26 will be used to increase the working fluid pressure in the test system to carry out water pressure tests and mechanical strength tests on the supercritical carbon dioxide heat exchanger to be tested; the charging and discharging module 27 will be used to charge or discharge the working fluid into the test system, absorb the small pressure fluctuations caused by heating or cooling in the test device, and maintain the stability of the test platform and the measurement accuracy.

[0150] Each functional module includes a module housing 28 and an interface flange 29. The module housing 28 may be a shell including a container, a pressure vessel, etc., and the specifications are exactly the same, so as to facilitate modular disassembly and transportation. The interface flange 29 may be a flat flange, a butt-weld flange, etc.

[0151] The connection sequence of each functional module in the test system can be changed, increased or decreased without affecting normal use, such as changing the heating module or cooling module to change the heat load and cooling capacity of the test system, such as increasing the number of modules to be tested to simultaneously measure multiple supercritical carbon dioxide heat exchangers to be tested;

[0152] Measuring instruments or regulating valves can be added arbitrarily between the various functional modules in the test system. For example, thermocouples and pressure transmitters can be added before and after the measuring module to measure the inlet and outlet temperature pressure of the supercritical carbon dioxide heat exchanger to be tested, or regulating valves can be added to the test branch to control the flow rate. Connecting pipes including metal, non-metal and other structural materials can be used between the various functional modules. The supercritical carbon dioxide heat exchanger 211 to be tested can include various types of heat exchange equipment such as microchannel compact supercritical carbon dioxide heat exchangers with various internal structures and sizes, plate supercritical carbon dioxide heat exchangers, and shell-and-tube supercritical carbon dioxide heat exchangers. The measurable heat exchange working fluids include different fluids such as carbon dioxide, water, and helium.

[0153] The module to be tested 21 is composed of a supercritical carbon dioxide heat exchanger 211 to be tested, a moving platform 212, a module housing 28 and an interface flange 29, wherein the supercritical carbon dioxide heat exchanger 211 to be tested is a heat exchange device with four interfaces, namely, inlet and outlet on both the cold and hot sides. The module housing 28 and the interface flange 29 are unified standardized components of the entire test system. The former packages all the main equipment and the latter connects all the main equipment to provide quick connection between each module.

[0154] The supercritical carbon dioxide heat exchanger 211 to be tested is integrally fixed on the moving platform 212 by the bottom angle bolts of the equipment, and can shake with the shaking of the moving platform 212. The inlet and outlet of the working fluid to be tested of the supercritical carbon dioxide heat exchanger 211 to be tested are connected to the two interface flanges 29 of the module through high-pressure hoses, and the inlet and outlet on the other side are connected to the cold source providing cooling water through a pipeline. The working fluid to be tested enters the supercritical carbon dioxide heat exchanger 211 to be tested, and flow heat transfer occurs between the working fluid on the other side.

[0155] The cooling module 22 is composed of a cooler 221, a module housing 28 and an interface flange 29, wherein the cooler 221 is a heat exchange device with four interfaces, namely, inlet and outlet on both the hot and cold sides. The inlet and outlet on the hot side are fixed to the two interface flanges 29 of the module by welding, and the inlet and outlet on the cold side are connected to a cold source providing cooling water through a pipeline. The working fluid to be tested with a higher temperature enters the cooler through the hot side and is cooled to a temperature close to the ambient temperature before flowing out of the module. The form of the cooler in the cooling module includes a variety of cooling devices such as a serpentine heat exchanger and a shell-and-tube heat exchanger, and the cooling liquid includes a variety of liquids such as water and oil.

[0156] The heating module 23 is composed of a preheater 231, a module housing 28 and an interface flange 29, wherein the inlet and outlet ends of the preheater 231 are respectively connected to the two interface flanges 29 of the module for fixing, and the preheater 231 adopts double-end power supply for direct heating, and the electrodes at both ends are connected to the power supply outside the module through cables. The preheater in the heating module includes various forms of heating equipment such as direct heating and indirect heating.

[0157] The modification module 24 consists of a mixing tank 241, a modification interface 242, a module housing 28 and an interface flange 29, wherein the inlet and outlet ends of the mixing tank 241 are respectively connected to the two interface flanges 29 of the module for fixation, and the modification interface 242 on the top of the mixing tank 241 can be used to add modification agents or impurities, which are fully mixed through the large space of the mixing tank 241 and enter the entire test system.

[0158] The driving module 25 is composed of a driving pump 251, a regulating valve 252, a module housing 28 and an interface flange 29, wherein the driving pump 251 and the regulating valve 252 are connected in parallel through a pipeline to form a test system bypass. During the test, most of the flow passes through the regulating valve 252 and is regulated by it to accurately adjust the flow of the entire test system. The two ends after parallel connection are respectively fixed to the two interface flanges 29 of the module by welding. The driving pump in the driving module includes various devices for driving fluids such as centrifugal pumps and magnetic pumps.

[0159] The pressurization module 26 consists of a boosting pump 261, a boosting interface 262, a module housing 28 and an interface flange 29, wherein the outlet of the boosting pump 261 is connected to the interface flange 29 by pipe welding to complete the fixation, and the boosting interface 262 is connected to an external device to realize the working fluid pressurization in the test system.

[0160] The charging and discharging module 27 is composed of a pressure regulator 271, a gas bottle 272, a module housing 28 and an interface flange 29, wherein the bottom interface of the pressure regulator 271 is welded to the interface flange 29 of the module through a pipeline, and the top interface is connected to the gas bottle 272 through a high-pressure hose. The pressure-stabilizing gas used by the pressure regulator in the charging and discharging module can use a variety of inert gases including nitrogen, helium, etc.

[0161] The module to be tested 21, the cooling module 22, the heating module 23, the modification module 24 and the driving module 25 are sequentially connected to form a loop through pipes and interface flanges 29, wherein the charging and discharging module 27 is connected between the module to be tested 21 and the heating module 23 through pipes and tees, and the pressurizing module 26 is connected between the module to be tested 21 and the cooling module 22 through pipes and tees.

[0162] The dimensions of all module housings 28 are exactly the same, which is convenient for processing and modular assembly, and greatly reduces the footprint of the test system. For the cooling modules 22 and heating modules 23, they can be increased or decreased according to the requirements of the parameter range measured by the test system, that is, the cooling capacity or heating capacity of the test system can be increased by connecting the cooling modules 22 or heating modules 23 in series through pipelines.

[0163] Four measurement components can be installed on the supercritical carbon dioxide heat exchanger 211 to be tested, including a temperature measurement component 4, a pressure measurement component 5, a strain measurement component 6 and a corrosion measurement component 7. The first three components can be installed on the heat exchange core 11, the end portion 12 or the connecting pipe 13, and the corrosion measurement component 7 can only be installed on the end portion 12 or the connecting pipe 13.

[0164] like Fig.12 and Fig.13 As shown, the temperature measuring component 4 is composed of a temperature measuring joint 41, a first cap nut 42, a first perforated copper pad 43, a temperature measuring instrument 44, a fastening nut 45, a rubber pad 46 and a temperature measuring screw hole 47.

[0165] Among them, the temperature measuring joint 41 is provided with an external thread adapted to the temperature measuring screw hole 47, and the temperature measuring instrument 44 is arranged in the temperature measuring screw hole 47. The temperature measuring joint 41 needs to connect the first cap nut 42 and the surface of the supercritical carbon dioxide heat exchanger, so the temperature measuring joint 41 is divided into a two-section structure, including a cylindrical section and a round rod section. The top of the first cap nut 42 is provided with a first through hole adapted to the temperature measuring instrument 44, and the inside of the temperature measuring joint 41 is provided with a second through hole coaxial with the first through hole.

[0166] The temperature measuring instrument 44 can be a thermocouple, a thermal resistor, an optical fiber probe or other temperature measuring device. A preferred option is a practical thermocouple thermometer. A thermometer made using the thermoelectric properties of a thermocouple is called a thermocouple thermometer. In general, a thermocouple thermometer is made by welding (or twisting) one end of two conductors A and B made of different materials. The two unwelded ends of the conductors are connected to the display instrument through connecting wires to form a temperature measurement system. When measuring temperature, the welding end of the thermocouple is brought into contact with the object to be measured, and the temperature of the object to be measured is converted into a corresponding electrical signal using the thermoelectric properties of the thermocouple and transmitted to the display instrument.

[0167] The temperature measuring joint 41, the first cap nut 42 and the first perforated copper pad 43 fix the temperature measuring instrument 44, and an external thread is set on the round rod section of the temperature measuring joint 41, which is fixedly connected to the temperature measuring surface through the external thread, so that the temperature measuring instrument 44 is placed in the temperature measuring screw hole 47 to achieve the purpose of temperature measurement.

[0168] Before installing the temperature measuring instrument 44, the temperature measuring joint 41 and the first cap nut 42, it is necessary to first drill a hole on the surface of the supercritical carbon dioxide heat exchanger using a drilling machine and tap it to form a temperature measuring screw hole 47. The temperature measuring instrument 44 can pass through the first through hole of the first cap nut 42 and be inserted into the second through hole of the temperature measuring joint 41. Therefore, it is necessary to ensure that the first through hole and the second through hole are coaxially arranged when the first cap nut 42 is connected to the temperature measuring joint 41.

[0169] The cylindrical section has a first end and a second end, and the outer side surface of the cylindrical section is provided with an external thread that is compatible with the first cap nut 42; the round rod section has a first end and a second end, the first end of the round rod section is coaxial with the second end face of the cylindrical section and is vertically fixedly connected, the second end of the round rod section is the temperature measuring point, and the round rod section is provided with an external thread that is compatible with the temperature measuring screw hole 47; that is, the second through hole is provided inside the cylindrical section and the round rod section, and the two-section structure can be a welded structure or an integrally formed structure.

[0170] The first perforated copper pad 43 is arranged in the first cap nut 42 and is located between the top inner side surface of the first cap nut 42 and the first end surface of the cylindrical section. A center hole is arranged in the center of the first perforated copper pad 43. The first perforated copper pad 43 has a certain elasticity, and whether to apply pressure to the first perforated copper pad 43 can be controlled by changing the position of the cylindrical section in the first cap nut 42. In order to better fix and apply pressure to the first perforated copper pad 43, the first cap nut 42 in this embodiment has a threaded section and a non-threaded section, the first end of the non-threaded section is connected to the top of the first cap nut 42, the second end of the non-threaded section is connected to the first end of the threaded section, the second end of the threaded section is connected to the end surface of the connecting end of the first cap nut 42, and the length of the cylindrical section is not less than the length of the threaded section.

[0171] When the first perforated copper pad 43 is in a compressed state, the thickness of the first perforated copper pad 43 is equal to the length of the non-threaded section, that is, the first perforated copper pad 43 is located in the non-threaded section. The diameter of the center hole of the first perforated copper pad 43 becomes smaller due to compression, so that the center hole and the temperature measuring instrument 44 have an interference fit, so that the first perforated copper pad 43 fixes the position of the temperature measuring instrument 44, so that the first cap nut 42, the first perforated copper pad 43, the temperature measuring joint 41 and the temperature measuring instrument 44 form a whole.

[0172] When the first perforated copper pad 43 is in a non-compressed state, the thickness of the first perforated copper pad 43 is greater than the length of the non-threaded section, that is, the first perforated copper pad 43 is located in the non-threaded section and the threaded section. At this time, the diameter of the center hole of the first perforated copper pad 43 does not change, and it is greater than the diameter of the temperature measuring instrument 44. The center hole and the temperature measuring instrument 44 are clearance-matched, so that the temperature measuring instrument 44 can be taken out.

[0173] In order to achieve free installation of the temperature measuring instrument 44, it is necessary to set the inner diameter of the first through hole to be larger than the diameter of the temperature measuring instrument 44, and the inner diameter of the second through hole to be larger than the diameter of the temperature measuring instrument 44; in order for the temperature measuring instrument 44 to be able to normally penetrate into the temperature measuring screw hole 47 after installing the temperature measuring instrument 44 on the surface of the supercritical carbon dioxide heat exchanger to be measured, the length of the temperature measuring instrument 44 is greater than the sum of the lengths of the first cover nut 42 and the temperature measuring joint 41.

[0174] In the above embodiment, the external thread of the cylindrical section is directly connected to the temperature measuring screw hole 47. Therefore, in general, the diameter of the temperature measuring screw hole 47 is small. Therefore, there may be a situation where the connection between the temperature measuring component 4 and the surface of the supercritical carbon dioxide heat exchanger 211 to be measured is unstable. This embodiment provides auxiliary fixing components, namely, a fastening nut 45 and a rubber pad 46. The interior of the fastening nut 45 is provided with an internal thread that is compatible with the external thread of the cylindrical section; the rubber pad 46 is arranged between the fastening nut 45 and the surface of the supercritical carbon dioxide heat exchanger to be measured.

[0175] By applying a force toward the surface of the supercritical carbon dioxide heat exchanger to be tested to the rubber pad 46 through the fastening nut 45, the fastening nut 45 applies an outward pulling force to the cylindrical section, so that the cylindrical section is more tightly connected to the surface of the supercritical carbon dioxide heat exchanger to be tested, achieving the purpose of self-locking. At the same time, through the friction between the rubber pad 46 and the surface of the supercritical carbon dioxide heat exchanger to be tested, the clamped temperature measuring instrument 44 is fixed on the surface of the supercritical carbon dioxide heat exchanger to be tested, preventing the measuring point from sliding.

[0176] In addition, because the screw-in position needs to be determined, scales are provided on the outer sides of the cylindrical segment, the round rod segment and the fastening nut 45. By observing the scales, the length of the round rod segment screwed into the temperature measuring screw hole 47, the length of the cylindrical segment screwed into the first cover nut 42, and the position of the fastening nut 45 on the round rod segment can be determined.

[0177] The first cap nut 42, the temperature measuring joint 41 and the fastening nut 45 can be made of any machinable material including stainless steel, iron, aluminum, etc. The first perforated copper pad 43 can also be made of any material other than copper that is easy to produce plastic deformation, and the rubber pad 46 can also be made of any material other than rubber that is easy to produce elastic deformation.

[0178] like Fig.14 and Fig.15 As shown, the pressure measuring assembly 5 is composed of a pressure measuring joint 51, a second cap nut 52, a second perforated copper washer 53, a pressure measuring tube 54 and a pressure measuring screw hole 55.

[0179] The pressure measuring joint 51 is provided with an external thread adapted to the pressure measuring screw hole 55, and the pressure measuring tube 54 is arranged in the pressure measuring screw hole 55. The pressure measuring joint 51 needs to connect the second cap nut 52 and the surface of the supercritical carbon dioxide heat exchanger to be tested, so the pressure measuring joint 51 is divided into a two-section structure, including a cylindrical section and a round rod section. The top of the second cap nut 52 is provided with a first through hole adapted to the pressure measuring tube 54, and the inside of the pressure measuring joint 51 is provided with a second through hole coaxial with the first through hole.

[0180] The pressure measuring tube 54 can be made of seamless stainless steel tube or capillary tube. The pressure measuring system is formed by connecting an external pressure transmitter. When measuring pressure, the pressure measuring screw hole is connected to the microchannel of the supercritical carbon dioxide heat exchanger 211 to be measured and the pressure measuring tube 54. The working fluid to be measured flows out of the equipment through the pressure measuring tube 54 and enters the pressure transmitter and other instruments. The pressure of the measured object is converted into a corresponding electrical signal by using the characteristics of the transmitter and transmitted to the display instrument.

[0181] The pressure measuring joint 51, the second cap nut 52 and the second perforated copper pad 53 fix the pressure measuring tube 54, and an external thread is set on the round rod section of the pressure measuring joint 51, which is fixedly connected to the pressure surface to be measured through the external thread, so that the pressure measuring tube 54 is placed in the pressure measuring screw hole 55 to achieve the purpose of temperature measurement.

[0182] Before installing the pressure measuring tube 54, the pressure measuring joint 51 and the second cap nut 52, it is necessary to first use a drilling machine to drill a hole on the surface of the supercritical carbon dioxide heat exchanger to be tested to connect the microchannel, and tap it to form a pressure measuring screw hole 55. The pressure measuring tube 54 can pass through the first through hole of the second cap nut 52 and insert it into the second through hole of the pressure measuring joint 51. Therefore, it is necessary to ensure that the first through hole and the second through hole are coaxially arranged when the second cap nut 52 is connected to the pressure measuring joint 51.

[0183] The cylindrical section has a first end and a second end, and the outer side surface of the cylindrical section is provided with an external thread that is compatible with the second cap nut 52; the round rod section has a first end and a second end, the first end of the round rod section is coaxial with the second end face of the cylindrical section and is vertically fixedly connected, the second end of the round rod section is a pressure measuring point, and the round rod section is provided with an external thread that is compatible with the pressure measuring screw hole 55; that is, the second through hole is provided inside the cylindrical section and the round rod section, and the two-section structure can be a welded structure or an integrally formed structure.

[0184] The second perforated copper pad 53 is arranged in the second cap nut 52 and is located between the top inner side surface of the second cap nut 52 and the first end surface of the cylindrical section. A center hole is arranged in the center of the second perforated copper pad 53. The second perforated copper pad 53 has a certain elasticity, and whether to apply pressure to the second perforated copper pad 53 can be controlled by changing the position of the cylindrical section in the second cap nut 52. In order to better fix and apply pressure to the second perforated copper pad 53, the second cap nut 52 in this embodiment has a threaded section and a non-threaded section, the first end of the non-threaded section is connected to the top of the second cap nut 52, the second end of the non-threaded section is connected to the first end of the threaded section, the second end of the threaded section is connected to the end surface of the connecting end of the second cap nut 52, and the length of the cylindrical section is not less than the length of the threaded section.

[0185] When the second perforated copper pad 53 is in a compressed state, the thickness of the second perforated copper pad 53 is equal to the length of the non-threaded section, that is, the second perforated copper pad 53 is located in the non-threaded section. The diameter of the center hole of the second perforated copper pad 53 becomes smaller due to compression, so that the center hole and the pressure measuring tube 54 have an interference fit, so that the second perforated copper pad 53 fixes the position of the pressure measuring tube 54, so that the second cap nut 52, the second perforated copper pad 53, the pressure measuring joint 51 and the pressure measuring tube 54 form a whole.

[0186] When the second perforated copper pad 53 is in a non-compressed state, the thickness of the second perforated copper pad 53 is greater than the length of the non-threaded section, that is, the second perforated copper pad 53 is located in the non-threaded section and the threaded section. At this time, the diameter of the center hole of the second perforated copper pad 53 does not change, and it is greater than the diameter of the pressure measuring tube 54. The center hole and the pressure measuring tube 54 are clearance-matched, so that the pressure measuring tube 54 can be taken out.

[0187] In order to achieve free installation of the pressure measuring tube 54, it is necessary to set the inner diameter of the first through hole to be larger than the diameter of the pressure measuring tube 54, and the inner diameter of the second through hole to be larger than the diameter of the pressure measuring tube 54; in order for the pressure measuring tube 54 to be able to normally penetrate into the pressure measuring screw hole 55 after the pressure measuring tube 54 is installed on the surface of the supercritical carbon dioxide heat exchanger to be tested, the length of the pressure measuring tube 54 is greater than the sum of the lengths of the second cover nut 52 and the pressure measuring joint 51.

[0188] like Fig.16 and Fig.17 As shown, the strain measuring assembly 6 is composed of a strain measuring joint 61 , a strain column 62 , a strain measuring screw hole 63 and a measuring wire 64 .

[0189] The strain measuring joint 61 is provided with an external thread adapted to the strain measuring screw hole 63, and the strain columns 62 are evenly arranged around the circumference of the strain measuring joint 61. The strain measuring joint 61 needs to connect the strain columns 62 and the surface of the supercritical carbon dioxide heat exchanger to be measured, so the strain measuring joint 61 is divided into a two-section structure, including a cylindrical section and a round rod section. The strain measuring joint 61 is a solid structure without internal through holes.

[0190] The strain column 62 may be made of an integral deformable material or a thick and thin two-stage sleeve structure, and can change resistance through its own deformation, thereby transmitting the strain change at the measuring point to the display instrument through the electrical signal of the measuring wire 64.

[0191] The round rod section of the strain measuring joint 61 is provided with an external thread, which is fixedly connected to the strain surface to be measured through the external thread, thereby achieving relative fixation of the strain measuring component 6 and the surface of the supercritical carbon dioxide heat exchanger to be measured. However, when local deformation occurs on the surface of the supercritical carbon dioxide heat exchanger to be measured, the strain measuring component 6 may have local relative rotation with the surface of the supercritical carbon dioxide heat exchanger to be measured. At this time, the strain columns 62 in all directions will show tension or compression, thereby achieving the purpose of strain measurement.

[0192] Before installing the strain measuring assembly 6, it is necessary to first drill a hole on the surface of the supercritical carbon dioxide heat exchanger to be measured by a drilling machine, and then tap the hole to form a strain measuring screw hole 63. One end of the strain column 62 is on the cylindrical section of the strain measuring joint 61, and the other end is bonded to the surface of the supercritical carbon dioxide heat exchanger to be measured, ensuring that the strain column 62 is evenly arranged circumferentially around the strain measuring joint 61.

[0193] The cylindrical segment has a first end and a second end, and the first end of the cylindrical segment is connected to the measuring wire 64; the round rod segment has a first end and a second end, and the first end of the round rod segment is coaxial with the second end face of the cylindrical segment and is vertically fixedly connected, the second end of the round rod segment is the strain measuring point, and the round rod segment is provided with an external thread that is compatible with the strain measuring screw hole 63; the two-section structure can be a welded structure or an integrally formed structure.

[0194] like Fig.18 and Fig.19 As shown, the corrosion detection assembly 7 is composed of a corrosion detection joint 71, a third cap nut 72, a blind copper gasket 73 and a collecting side hole 74.

[0195] Among them, the corrosion detection joint 71 needs to connect the third cap nut 72 and the surface of the supercritical carbon dioxide heat exchanger to be tested, so the corrosion detection joint 71 is divided into a two-section structure, including a cylindrical section and a round rod section. The third cap nut 72 needs to connect an external detection instrument and the corrosion detection joint 71, so the third cap nut 72 is also divided into a pipe section and an internal thread section. The third cap nut 72 is provided with a first through hole adapted to the external detection instrument, and the interior of the corrosion detection joint 71 is provided with a second through hole coaxial with the first through hole.

[0196] Before installing the corrosion detection assembly 7, it is necessary to first drill a hole on the surface of the end cap 12 or the connecting pipe 13 by a drilling machine, the hole diameter of which is equal to the outer diameter of the round rod segment, and then insert the corrosion detection joint 71 for welding. The working fluid to be detected can pass through the first through hole of the connecting pipe segment of the third cap nut 72 and flow into the second through hole of the corrosion detection joint 71, so it is necessary to ensure that the first through hole and the second through hole are coaxially arranged when the third cap nut 72 is connected to the corrosion detection joint 71.

[0197] The cylindrical section has a first end and a second end, and the outer side surface of the cylindrical section is provided with an external thread adapted to the third cover nut 72; the round rod section has a first end and a second end, and the first end of the round rod section is coaxial with and vertically fixed to the second end face of the cylindrical section, and a large number of evenly arranged collecting side holes 74 are drilled on the second end of the round rod section; that is, the second through hole is provided inside the cylindrical section and the round rod section, and the two-section structure can be a welded structure or an integrally formed structure.

[0198] The blind copper pad 73 is arranged in the third cap nut 72 and is located between the inner side surface of the top of the third cap nut 72 and the first end surface of the cylindrical section; the blind copper pad 73 has a certain elasticity, and whether to apply pressure to the blind copper pad 73 can be controlled by changing the position of the cylindrical section in the third cap nut 72. In order to better fix and apply pressure to the blind copper pad 73, the third cap nut 72 in this embodiment has a threaded section and a non-threaded section, the first end of the non-threaded section is connected to the top of the third cap nut 72, the second end of the non-threaded section is connected to the first end of the threaded section, the second end of the threaded section is connected to the end surface of the connecting end of the third cap nut 72, and the length of the cylindrical section is not less than the length of the threaded section;

[0199] When the blind copper pad 73 is in a compressed state, the thickness of the blind copper pad 73 is equal to the length of the non-threaded section, that is, the blind copper pad 73 is located in the non-threaded section. The blind copper pad 73 is compressed, resulting in an interference fit between the corrosion testing joint 71, the third cap nut 72 and the blind copper pad 73, thereby preventing the working fluid to be tested from flowing out of the corrosion testing component 7 through the collecting side hole 74.

[0200] When the blind copper pad 73 is in a non-compressed state, the thickness of the blind copper pad 73 is greater than the length of the non-threaded section, that is, the blind copper pad 73 is located inside the non-threaded section and the threaded section. At this time, the size of the blind copper pad 73 does not change, and it is clearance-matched with the corrosion detection joint 71 and the third cap nut 72, so that the working fluid to be detected can flow out of the corrosion detection component 7 through the collecting side hole 74.

[0201] Combine the following Fig. 20 A test method of a multi-physics coupling test system for a supercritical carbon dioxide heat exchanger of the present invention is further explained. The test method comprises the following steps in sequence:

[0202] Step 1b: According to the design parameter range of the supercritical carbon dioxide heat exchanger 211 to be tested, the required number of cooling modules 22 and heating modules 23 are selected, holes are drilled on the supercritical carbon dioxide heat exchanger 211 to be tested, and various components (temperature measurement component 4, pressure measurement component 5, strain measurement component 6 and corrosion measurement component 7) are installed and fixed on the motion table 212, and all equipment is fixed in the module housing 28 through metal brackets, and the corresponding interfaces are connected to the interface flange 29 of uniform size. After connecting the necessary measuring instruments, each module is connected to the corresponding interface flange 29 through pipes, and the electrical, measurement and control, charging and exhaust, cooling pipelines and other lines are connected to the corresponding external equipment to complete the construction of the test system.

[0203] Step 2b, charge a quantitative operating fluid into the test system through the charging and discharging module 27, and then charge the pressure-stabilizing gas to stabilize the system to the design pressure, start and adjust the driving module 25, and adjust the cooling module 22 and the heating module 23 to make the inlet temperature, pressure and flow of the supercritical carbon dioxide heat exchanger 211 to be tested reach the design values; according to the requirements of the corrosion characteristic test of the supercritical carbon dioxide heat exchanger 211 to be tested, add a certain amount of other substances into the system through the modification module 24 until the test requirements are met; according to the requirements of the strength characteristic test of the supercritical carbon dioxide heat exchanger 211 to be tested, increase the pressure in the system through the pressurization module 26 until the test requirements are met.

[0204] Step 3b, start all the measurement and control instruments on the supercritical carbon dioxide heat exchanger 211 to be tested, collect the flow, heat transfer, strain and corrosion parameters of the supercritical carbon dioxide heat exchanger 211 to be tested, and calculate the multi-physics coupling performance of the supercritical carbon dioxide heat exchanger 211 to be tested.

[0205] Step 4b, after completing the measurement of the parameter, continue to adjust each module to reach the next measurement point, and repeat the above step 3b. If you want to change the structure of the supercritical carbon dioxide heat exchanger 211 to be tested, you only need to remove the interface flange 29 to disconnect the module 21 to be tested, cut off the inlet and outlet pipelines of the supercritical carbon dioxide heat exchanger 211 to be tested, and reconnect the module after replacement.

[0206] The supercritical carbon dioxide heat exchanger is used for two or more working fluids to flow and exchange heat therein. The supercritical carbon dioxide heat exchanger uses high-precision microchannel forming technologies such as etching and machining and vacuum diffusion welding technologies, and uses the idea of ​​close arrangement to arrange a large number of microchannels in a "J" shape on a microchannel heat exchange plate of limited size, thereby realizing an efficient and compact supercritical carbon dioxide heat exchanger with the advantages of efficient operation and compact equipment. The multi-physics coupling test system for coupling the flow, heat transfer, strength and corrosion resistance characteristics of the supercritical carbon dioxide heat exchanger uses the idea of ​​modular construction to modularly disassemble the large test system, thereby realizing a multifunctional, high-precision, fast-response performance test system and test method for the supercritical carbon dioxide heat exchanger.

[0207] The test system includes a module to be tested, a cooling module, a driving module, a heating module, a charging and discharging module, a modification module, and a pressure module. The supercritical carbon dioxide heat exchanger has the characteristics of wide-range adjustable working fluid flow rate and weakened axial heat conduction and other adverse effects. Compared with the traditional shell and tube heat exchanger, the present invention can significantly reduce the system volume while achieving the same heat exchange requirements; the test system has the characteristics of easy module assembly and modification and multi-function. Compared with traditional thermal hydraulic or other single test systems, the present invention can continuously carry out wide-parameter, multi-physics coupled heat exchanger performance tests on one test system, and has broad application prospects.

[0208] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A design method for a supercritical carbon dioxide heat exchanger, characterized in that: The supercritical carbon dioxide heat exchanger (1) comprises a heat exchange core (11), a head portion (12) and a connecting portion (13); the heat exchange core (11) contains a microchannel (111); the microchannel (111) comprises a plurality of first microchannels (1111) and a plurality of second microchannels (1112); the head portion (12) comprises a first inlet head (121), a first outlet head (122), a second inlet head (123) and a second outlet head (124); the connecting portion (13) comprises a first inlet head (121), a first outlet head (122), a second inlet head (123) and a second outlet head (124); The first inlet pipe (131), the first inlet end cap (121), the first microchannel (1111), the first outlet end cap (122) and the first outlet pipe (132) are connected in sequence, and the second inlet pipe (133), the second inlet end cap (123), the second microchannel (1112), the second outlet end cap (124) and the second outlet pipe (134) are connected in sequence; The design method of the supercritical carbon dioxide heat exchanger comprises the following steps in sequence: Step 1a, obtaining input parameters of working fluids on both sides; Step 2a: Preliminary selection of the size L of the heat exchange plate (112) x , L y and the width p of the blank area (114), calculate the size l of the supercritical carbon dioxide heat exchanger x and l y ; ； ； L x is the length of the heat exchange plate (112), in mm; L y is the width of the heat exchange plate (112), in mm; l x is the length of the heat exchange zone (115), in mm; l y is the width of the heat exchange area (115), in mm; the width p of the blank area (114) is in mm; Step 3a, selecting the width d of the microchannel (111) and the width t of the rib wall (116) of the working fluid on both sides according to the processing restrictions and mechanical strength criteria of the microchannel (111), wherein the unit of the width d of the microchannel (111) is mm, and the unit of the width t of the rib wall (116) is mm; Step 4a, preliminarily setting the number of revolutions M of the microchannels (111) of the working fluid on both sides to be 1 and the number of microchannel groups N to be 1; the number of revolutions M has no unit, and the number of microchannel groups N has no unit; Step 5a: Based on the values ​​of M and N and the l calculated in the above steps x and l y The result is to look up the table to estimate W, and then based on the formula Calculate S, and finally calculate the single board flow area A based on W and S h and heat exchange area S h ; ； ； W is the flow width, in mm; S is the flow length, in mm; n is the number of microchannels, without unit; Step 6a, carry out thermal hydraulic design calculations, and adjust M and N according to whether the results meet the design input, until the requirements of flow and heat transfer characteristics are met at the same time; Step 7a: Re-calculate W and S, carry out thermal hydraulic verification calculations, and compare again whether the requirements of flow and heat transfer characteristics are met. If not, return to the previous step until the design requirements are met, and then proceed to the next step; Step 8a: Draw the construction drawings of the heat exchange plates (112) on both sides.

2. The design method of the supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The heat exchange core (11) comprises a plurality of heat exchange plates (112) arranged in a stacked manner, and the heat exchange plates (112) are welded to each other, wherein the welding is diffusion welding, brazing or fusion welding.

3. The design method of the supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The heat exchange core (11) and the end portion (12) are welded, and the end portion (12) and the connecting pipe portion (13) are welded, and the welding is argon arc welding, brazing or ion welding.

4. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The heat exchange core (11) contains a plurality of stacked heat exchange plates (112), wherein the heat exchange plates (112) include a primary side heat exchange plate (1121) and a secondary side heat exchange plate (1122), wherein the first microchannel (1111) is located in the primary side heat exchange plate (1121), and the second microchannel (1112) is located in the secondary side heat exchange plate (1122); the stacked arrangement of the heat exchange plates (112) in the heat exchange core (11) is as follows: one primary side heat exchange plate (1121) and one secondary side heat exchange plate (1122) are alternately arranged, or one primary side heat exchange plate (1121) and two secondary side heat exchange plates (1122) are alternately arranged, or two primary side heat exchange plates (1121) and one secondary side heat exchange plate (1122) are alternately arranged.

5. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The heat exchange core (11) comprises a plurality of stacked heat exchange plates (112), the thickness of the heat exchange plates (112) is 1 mm to 5 mm, and the cross-sectional dimension of the microchannel (111) is 1 mm to 10 mm.

6. The design method of a supercritical carbon dioxide heat exchanger according to claim 5, characterized in that: The microchannels (111) are linear or folded, and rib walls (116) are provided between the microchannels (111). The width of the rib walls (116) is 0.5 mm to 10 mm.

7. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The inner surface of the microchannel (111) is a rough surface, the inner surface of the microchannel (111) is connected to an attachment, or the inner surface of the microchannel (111) is connected to a vortex generator.

8. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The microchannels (111) are arranged in a "X" shape for rotational flow, and the number of times the microchannel (111) turns 180 degrees plus one is the number of rotations M, and the microchannels (111) are divided into N groups of microchannels (111) arranged in parallel with each other, wherein M and N are both natural numbers, wherein if M is an odd number, the inlet and outlet positions of the microchannel (111) are on the same side of the supercritical carbon dioxide heat exchanger, and if M is an even number, the inlet and outlet positions of the microchannel (111) are on opposite sides of the supercritical carbon dioxide heat exchanger.

9. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: A rounded transition is provided at the turning point of the microchannel (111).

10. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The microchannels (111) are in the shape of a cross. Rib walls (116) are provided between the microchannels (111). Transverse communication holes are provided in the rib walls (116). The shapes of the transverse communication holes include circular, semicircular or square.

11. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The microchannel (111) further comprises a third microchannel, the end portion (12) further comprises a third inlet end portion and a third outlet end portion, and the pipe portion (13) further comprises a third inlet pipe and a third outlet pipe; the third inlet pipe, the third inlet end portion, the third microchannel, the third outlet end portion and the third outlet pipe are connected in sequence.

12. The design method of a supercritical carbon dioxide heat exchanger according to claim 1, characterized in that: The heat exchange plate (112) contains a blank area (114) and a heat exchange area (115), and the microchannel (111) and the rib wall (116) are both located in the heat exchange area (115).

13. The design method of a supercritical carbon dioxide heat exchanger according to claim 12, characterized in that: The flow width W and flow length S of the microchannel (111) at the inlet or outlet position are respectively: ； ； W0 is the width of the microchannel group, in mm; W x is the lateral gap, in mm; H is the height of the microchannel group, in mm; W y It is the longitudinal gap in mm.

14. The design method of a supercritical carbon dioxide heat exchanger according to claim 13, characterized in that: Under the premise that the microchannel (111) is semicircular, the single plate flow area A of the supercritical carbon dioxide heat exchanger is h And the single plate heat exchange area S h They are: and .

15. A multi-physics coupling test system for a supercritical carbon dioxide heat exchanger, wherein the supercritical carbon dioxide heat exchanger is a supercritical carbon dioxide heat exchanger designed by the design method according to any one of claims 1 to 14, characterized in that: The multi-physics coupling test system (2) comprises a plurality of functional modules, wherein the plurality of functional modules are: A module to be tested (21), used for installing a supercritical carbon dioxide heat exchanger to be tested (211); A cooling module (22) for cooling the test working fluid flowing out of the supercritical carbon dioxide heat exchanger (211) to be tested; A heating module (23) is used to preheat the test working fluid to a designed temperature value so that the working fluid reaches the inlet of the supercritical carbon dioxide heat exchanger (211) to be tested; A modification module (24) is used to add different types of substances to the multi-physics coupling test system (2) to achieve working fluid modification; A driving module (25), used for driving the test working fluid to operate; A pressure module (26) for increasing the pressure of the working fluid in the multi-physics coupling test system (2); The charging and discharging module (27) is used to charge or discharge working fluid into the multi-physics coupling test system (2).

16. The multi-physics coupling test system according to claim 15, characterized in that: The module housing (28) of each functional module is a container or a pressure vessel, the module housing (28) of each functional module is the same, and each functional module contains an interface flange (29).

17. The multi-physics coupling test system according to claim 15, characterized in that: The multi-physics coupling test system is capable of testing a variety of different supercritical carbon dioxide heat exchangers (211) to be tested, and the heat exchange working fluids that can be tested by the multi-physics coupling test system include carbon dioxide, water and helium.

18. The multi-physics coupling test system according to claim 15, characterized in that: The cooler (221) inside the cooling module (22) is a serpentine tube heat exchanger or a shell-and-tube heat exchanger, and the cooling liquid used in the cooling module (22) is water or oil.

19. The multi-physics coupling test system according to claim 15, characterized in that: The driving module (25) contains a driving pump (251), and the driving pump (251) is a centrifugal pump or a magnetic pump.

20. The multi-physics coupling test system according to claim 15, characterized in that: The charging and discharging module (27) contains a pressure stabilizer (271), the pressure stabilizer (271) adopts a non-contact pressure container, and the pressure stabilizing gas is nitrogen or helium.

21. The multi-physics coupling test system according to claim 15, characterized in that: A plurality of measurement components are installed on the supercritical carbon dioxide heat exchanger (211) to be measured, wherein the plurality of measurement components include a temperature measurement component (4), a pressure measurement component (5), a strain measurement component (6) and a corrosion measurement component (7).

22. The multi-physics coupling test system according to claim 21, characterized in that: The temperature measuring assembly (4) comprises a temperature measuring joint (41), a first cap nut (42), a first perforated copper pad (43), a temperature measuring instrument (44), a fastening nut (45), a rubber pad (46) and a temperature measuring screw hole (47). The temperature measuring instrument (44) can be fixed by adjusting the relative position of the temperature measuring joint (41) and the first cap nut (42) to adjust the pressure state of the first perforated copper pad (43).

23. The multi-physics coupling test system according to claim 21, characterized in that: The pressure measuring assembly (5) comprises a pressure measuring joint (51), a second cap nut (52), a second copper washer with holes (53), a pressure measuring tube (54) and a pressure measuring screw hole (55). The pressure measuring tube (54) can be fixed by adjusting the relative position of the pressure measuring joint (51) and the second cap nut (52) to adjust the pressure state of the second copper washer with holes (53).

24. The multi-physics coupling test system according to claim 21, characterized in that: The strain measuring assembly (6) comprises a strain measuring joint (61), a strain column (62), a strain measuring screw hole (63) and a measuring wire (64), and measures the strain characteristics of the surface of the supercritical carbon dioxide heat exchanger (211) to be measured through the tension or compression state of the strain column (62).

25. The multi-physics coupling test system according to claim 21, characterized in that: The corrosion detection assembly (7) comprises a corrosion detection joint (71), a third cap-shaped nut (72), a blind copper gasket (73) and a collecting side hole (74). By adjusting the relative position of the corrosion detection joint (71) and the third cap-shaped nut (72) and adjusting the pressure state of the blind copper gasket (73), it is possible to adjust whether the working fluid flows out of the corrosion detection assembly (7) to detect the working fluid composition.

26. A test method for the multi-physics coupling test system according to claim 21, characterized in that: The test method comprises the following steps in sequence: Step 1b, constructing the multi-physics coupling test system according to the design parameter range of the supercritical carbon dioxide heat exchanger (211) to be tested; Step 2b, charging a quantitative operating fluid and a pressure-stabilizing gas into the multi-physics coupling test system through a charging and discharging module (27), starting and adjusting a cooling module (22) and a heating module (23) until the inlet parameters of the supercritical carbon dioxide heat exchanger (211) to be tested meet the design requirements; Step 3b: collecting different parameters on the supercritical carbon dioxide heat exchanger (211) to be tested by means of the multiple measurement components, and calculating and obtaining the multi-physical coupling characteristics of the supercritical carbon dioxide heat exchanger (211) to be tested; Step 4b: Adjust the parameters to the next measurement point and repeat step 3b above.

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