Working medium outside-pipe high-temperature-position boiling and condensation heat exchange device and method

Abstract

The invention belongs to the technical field of testing equipment, and provides a working medium outside-pipe high-temperature-position boiling and condensation heat exchange device and method.The device comprises a working medium circulating system, a cooling circulating system and a hot water circulating system, and during working, the cooling circulating system and the hot water circulating system can conduct heat exchange on media in the working medium circulating system; therefore, the medium is changed into steam to rise, and then is condensed and refluxed to simulate the heat exchange condition. Working medium circulation is completed through the height difference between the evaporator and the condenser, power devices such as a compressor or a shield pump are avoided, and the building cost is low; besides, heat exchange states of boiling and condensation outside a working medium pipe under different working conditions can be simulated, the working conditions are convenient to adjust, and construction is convenient; the heat source depends on convective heat transfer of hot water in the pipe, and compared with a test system adopting an electric heating pipe to provide heat, the heat exchange condition of the engineering actual heat exchange pipe can be simulated.

Description

Technical Field

[0001] This disclosure belongs to the field of testing equipment technology, and specifically relates to a heat exchange device and method for boiling and condensing at a high temperature outside the working fluid tube. Background Technology

[0002] Boiling and condensation are widespread in various industrial fields. Against the backdrop of global climate change, the types of organic working fluids are constantly being updated, and the types of enhanced tubes are constantly being iterated. Accurate and convenient determination of the phase change heat transfer coefficient of organic working fluids under different tube types and operating conditions is of great significance for the development and improvement of heat exchangers.

[0003] In existing technologies, to facilitate the control of heat flux density, evaporation often uses electric heating as the input heat source, such as the invention patent CN114544213B entitled "A Test System and Method for Determining the Boiling Heat Transfer Coefficient of a Working Fluid". This type of heat exchange device can only measure the boiling heat transfer coefficient outside the tube and cannot simulate the actual heat transfer process of water flowing inside the tube and the working fluid evaporating outside the tube, nor can it directly obtain the total heat transfer coefficient through experiments. Measurement devices using water as a heat source, such as the invention patent CN201710453004.9 entitled "Horizontal Tube Bundle and Single Tube External Refrigerant Falling Film Evaporation, Pool Boiling and Condensation Phase Change Heat Transfer Device", have an evaporation saturation temperature of -10℃ to -20℃ and a condensation saturation temperature of 30℃ to 50℃. The test conditions are limited to the low-temperature conditions of the refrigeration cycle and cannot simultaneously meet the high-temperature conditions of the organic Rankine cycle.

[0004] Currently, there is a relative lack of technology for measuring heat transfer in phase change experiments of heat exchange tubes. Existing heat exchange devices have a small operating condition adjustment range, are cumbersome, and are difficult to debug. In particular, there is a lack of corresponding measurement methods for the physical process of convective heat transfer inside the tube with water as the medium and boiling and condensation of the high-temperature working medium outside the tube. This seriously hinders the in-depth and detailed experimental research, and there is an urgent need to find a new type of measurement device to solve this problem. Summary of the Invention

[0005] To address the problems in the background art, this invention proposes a heat exchange device and method for boiling and condensing at a high temperature outside the working fluid tube.

[0006] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0007] A heat exchange device for boiling and condensing a working fluid at a high temperature outside the tube includes:

[0008] The working fluid circulation system includes an evaporator shell and a condenser shell with a height difference, wherein the evaporator shell is located below the condenser shell, and a steam pipe and a return pipe are connected between the evaporator shell and the condenser shell;

[0009] The cooling circulation system includes an electric heating wire and a condenser heat exchange tube; the condenser heat exchange tube is installed in the middle region inside the condenser shell; the electric heating wire is located at the bottom of the cooling circulation system.

[0010] A hot water circulation system, including evaporative heat exchange tubes, which are installed inside the evaporator shell.

[0011] Furthermore, in the working fluid circulation system, several temperature sensors are installed on the upper and lower surfaces of the evaporator shell, and a pressure sensor is installed at the center of the upper surface to acquire pressure and temperature data of the evaporator shell in real time.

[0012] Several temperature sensors are installed on the upper surface of the condenser shell, and a pressure sensor is installed at the center of the upper surface to acquire pressure and temperature data of the condenser shell in real time.

[0013] Furthermore, in the working fluid circulation system, an evaporation window is also installed on the surface of the evaporator shell at the position corresponding to the evaporation heat exchange tube. The evaporation window is used to observe the evaporation heat exchange tube inside the evaporator shell.

[0014] A condensing window is installed on the surface of the condenser shell at the position corresponding to the condensing heat exchange tube. The condensing window is used to observe the condensing heat exchange tube inside the condenser shell.

[0015] Furthermore, in the working fluid circulation system, an organic working fluid extraction port is provided on one side of the lower surface of the evaporator shell, and an organic working fluid charging port is provided on the same side of the upper surface of the condenser shell.

[0016] Furthermore, in a hot water circulation system, it includes:

[0017] The outlet of the evaporative heat exchange tube is connected in sequence to the first flow meter, three-way valve, plate heat exchanger, hot water pump and hot water tank through pipelines along the water outlet direction;

[0018] The outlet of the hot water tank, which is away from the hot water pump, is connected to the inlet of the evaporative heat exchange tube via a pipeline.

[0019] The electric heating element is installed at the bottom of the hot water tank;

[0020] An air vent valve is installed on top of the hot water tank;

[0021] One end of the first heat exchange tube of the plate heat exchanger is connected to the first flow meter through a pipeline, and the other end is connected to the hot water pump through a pipeline.

[0022] The water supply pump has two branch connections at its outlet. One branch is connected to the second heat exchange tube of the plate heat exchanger via a pipeline, and the other branch is connected to a three-way valve. The water supply pump inlet is connected to the cooling water tank via a pipeline.

[0023] The inlet of the cooling water tank is connected to the second heat exchange tube of the plate heat exchanger via a pipeline, and a straight-through valve is installed on the pipeline.

[0024] Temperature sensors are installed in the pipes at both the inlet and outlet of the evaporative heat exchange tube.

[0025] Furthermore, in the hot water circulation system, the second heat exchange tube of the plate heat exchanger and the water supply pump are both connected to the pipeline connected to the flow meter.

[0026] Furthermore, the cooling circulation system includes a refrigeration module and a water-cooling module. In the water-cooling module, along the direction of medium flow, the outlet of the condenser heat exchange tube is sequentially connected to a second flow meter, a cold water tank, and a cold water pump via a pipeline. Temperature sensors are installed on the pipelines at the inlet and outlet positions of the condenser heat exchange tube.

[0027] The electric heating wire is installed at the bottom of the cold water tank;

[0028] The outlet of the cold water pump, which is away from the cold water tank, is connected to the inlet of the condenser heat exchange tube via a pipeline;

[0029] A surface cooler is installed on the pipe at the inlet of the cold water tank;

[0030] The refrigeration module is used for refrigeration and heat exchange with the water-cooling module.

[0031] Furthermore, in the refrigeration module, an evaporator coil, a compressor, and a throttling valve are connected sequentially along the direction of medium flow;

[0032] The evaporator coil is located inside the cold water tank, with its inlet connected to a throttle valve via a pipe and its outlet connected to a compressor via a pipe.

[0033] The throttle valve is located outside the cold water tank;

[0034] The compressor is located outside the cold water tank;

[0035] A condenser coil is laid on the pipe between the throttle valve and the compressor.

[0036] A testing method, applied to the above-mentioned high-temperature boiling and condensation heat exchanger outside the working fluid tube, includes the following steps:

[0037] The medium in the evaporator heat exchange tube exchanges heat with the liquid in the evaporator shell, causing the liquid in the evaporator shell to heat up and generate steam.

[0038] During the steam rise process, the steam is introduced into the condenser shell through the steam pipe;

[0039] The medium in the condenser heat exchange tube is adjusted to the target temperature through the cooling circulation system, and at the same time, the medium at the target temperature is exchanged with steam to cool the steam and form a liquid.

[0040] Under the influence of gravity, the liquid is discharged to the evaporator shell through the return pipe.

[0041] Furthermore, heat exchange occurs between the medium in the evaporator heat exchange tubes and the liquid in the evaporator shell, including the following steps:

[0042] The medium inside the evaporative heat exchange tube is heated by a hot water circulation system. If the medium temperature exceeds the target range, heat exchange is performed to cool it down until the medium temperature inside the evaporative heat exchange tube is within the target range. If the medium pressure is less than the target range, water is added by a water pump to bring the medium pressure within the target range.

[0043] The heated medium exchanges heat with the liquid in the evaporator shell until the liquid is converted into steam.

[0044] Furthermore, adjusting the medium within the condenser heat exchanger tubes to the target temperature via the cooling circulation system includes the following steps:

[0045] The electric heating wire assists in heating the medium inside the condenser heat exchange tube, while the refrigeration module in the cooling circulation system exchanges heat with the medium inside the condenser heat exchange tube until the temperature of the medium inside the condenser heat exchange tube is within the target range.

[0046] The beneficial effects of this disclosure are:

[0047] 1. This invention relies on the height difference between the evaporator and the condenser to complete the working fluid circulation, avoiding power devices such as compressors or canned pumps, resulting in low construction costs; in addition, it can simulate the heat exchange state of boiling and condensation outside the working fluid tube under different operating conditions, making it convenient to adjust the operating conditions and easy to build.

[0048] 2. The heat source disclosed herein relies on the convection heat transfer of hot water inside the pipe. Compared with the test system that uses electric heating tubes to provide heat, it can simulate the heat exchange situation of actual heat exchange tubes in engineering.

[0049] 3. The cold water circulation system of this test system incorporates electric heating, which can control the cooling water temperature between 0℃ and 80℃. When the water temperature exceeds 40℃, the compressor shuts down and the surface cooler is switched to lower the temperature, overcoming the high-temperature alarm problem of the compressor refrigeration cycle and providing cooling capacity under high-temperature conditions to maintain a constant cold water circulation temperature. The hot water circulation system relies on a water supply pump to pressurize and increase the water's saturation temperature. The water temperature reaches 120℃ without vaporization and is then added to the cooling water system to maintain a stable water temperature. In industrial organic Rankine cycle power generation, the evaporator and condenser heat exchangers operate at high temperatures. This heat exchange device can not only test the high-temperature conditions of the organic Rankine cycle but also meet the low-temperature conditions of the refrigeration cycle.

[0050] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the disclosure. The objectives and other advantages of this disclosure may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A schematic diagram of the structure of a working fluid external high-temperature boiling and condensation heat exchange device disclosed herein is shown.

[0053] Figure 2 A flowchart of a method for testing boiling and condensation heat exchange at high temperatures outside the working fluid tube, as disclosed in this disclosure, is shown.

[0054] In the diagram: 1. Evaporator shell; 2. Condenser shell; 3. Steam pipe; 4. Return pipe; 5. Temperature sensor; 6. Pressure sensor; 7. Condensation window; 8. Evaporation window; 9. Hot water pump; 10. Electric heating element; 11. Exhaust valve; 12. Flow meter; 13. Make-up water pump; 14. Plate heat exchanger; 15. Hot water tank; 16. Cooling water tank; 17. Evaporation heat exchange tube; 18. Evaporation coil; 19. Throttling valve; 20. Condensation coil; 21. Compressor; 22. Electric heating wire; 23. Cold water tank; 24. Cold water pump; 25. Surface cooler; 26. Condensation heat exchange tube; 27. Organic working fluid inlet; 28. Organic working fluid outlet; 29. ​​Straight-through valve; 30. Three-way valve. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0056] A heat exchange device for boiling and condensing working fluid at a high temperature outside the tube, such as Figure 1 As shown, it includes an organic matter circulation system, a cooling circulation system, and a hot water circulation system.

[0057] The working fluid circulation system includes an evaporator shell 1 and a condenser shell 2 with a height difference. The evaporator shell 1 is located below the condenser shell 2. A steam pipe 3 and a return pipe 4 are connected between the evaporator shell 1 and the condenser shell 2. The steam pipe 3 is used to introduce steam from the evaporator shell 1 into the condenser shell 2, and the return pipe 4 is used to introduce liquid from the condenser shell 2 into the evaporator shell 1.

[0058] In some embodiments, the evaporator shell 1 and condenser shell 2 can be made of 316 stainless steel, with a length of 1000 mm, an inner diameter of 160 mm, and a wall thickness of 8 mm, capable of withstanding a pressure of 2 MPa. This size is sufficient for the evaporation and condensation of the organic working fluid, provided the organic working fluid charge is relatively small. The outlet of the evaporator shell 1 is connected to the inlet of the condenser shell 2 via a steam pipe 3, and the outlet of the condenser shell 2 is connected to the inlet of the evaporator shell 1 via a return pipe 4. The steam pipe 3 and the return pipe 4 are stainless steel flexible hoses, which are heat-resistant, pressure-resistant, and have good ductility. The condenser shell 2 is located above the evaporator shell 1, with a center distance of 500 mm. The organic working fluid evaporates in the evaporator, and the vapor flows to the condenser above due to the pressure difference. After the working fluid condenses, the liquid flows back to the evaporator by gravity to complete the cycle.

[0059] In some embodiments, both the evaporator housing 1 and the condenser housing 2 are equipped with a pressure sensor 6 and several temperature sensors 5. The pressure sensor 6 and temperature sensors 5 can monitor the pressure and temperature data inside the evaporator housing 1 and the condenser housing 2 in real time. By analyzing these data, the state of the medium inside the evaporator housing 1 and the condenser housing 2 can be obtained, thereby facilitating the control of various parameters of the device.

[0060] It should be noted that, in Figure 1 Several temperature sensors 5 are installed on the upper and lower surfaces of the evaporator shell 1, and a pressure sensor 6 is installed at the center of the upper surface. Several temperature sensors 5 are installed on the upper surface of the condenser shell 2, and a pressure sensor 6 is installed at the center of the upper surface.

[0061] In some embodiments, an evaporation viewing window 8 is also installed on the surface of the evaporator shell 1 at a position corresponding to the evaporation heat exchange tube 17. The evaporation viewing window 8 is used to observe the evaporation heat exchange tube 17 inside the evaporator shell 1. A condensation viewing window 7 is installed on the surface of the condenser shell 2 at a position corresponding to the condensation heat exchange tube 26. The condensation viewing window 7 is used to observe the condensation heat exchange tube 26 inside the condenser shell 2.

[0062] It should be noted that the evaporator shell 1 and the condenser shell 2 each have two flange bases welded to the front and back. The condenser viewing window 7 and the evaporator viewing window 8 are both tempered glass. The viewing windows are fastened by flanges and gaskets. The flange pressure is 2 MPa. The viewing window diameter is 18 mm. The front and back viewing windows are symmetrical, with good lighting, and the condition of the heat exchange tubes can be clearly observed.

[0063] In some embodiments, in the working fluid circulation system, an organic working fluid extraction port 28 is provided on one side of the lower surface of the evaporator shell 1, and an organic working fluid charging port 27 is provided on the same side of the upper surface of the condenser shell 2.

[0064] It should be noted that both the organic working fluid inlet 27 and the organic working fluid outlet 28 are made of copper and are connected to the top of the condenser shell 2 and the bottom of the evaporator shell 1 respectively via threaded bases. During the pressure test, the air pump is connected to the organic working fluid outlet 28. The shell pressure is first increased to 0.4 MPa. If there is no leakage, the pressure gauge reading is recorded after half an hour. After maintaining the pressure for 4 hours, if the pressure change is less than 0.001 MPa, the pressure is increased to 0.8 MPa, and the above operation is repeated. If there is still no leakage, the pressure is increased to 1.6 MPa, and the above operation is repeated. If there is no leakage, the pressure is maintained for 24 hours. If the pressure gauge change is less than 0.005 MPa, the airtightness is considered good.

[0065] After the pressure test is successful, refrigerant charging begins. The vacuum pump and working fluid tank are connected to the organic working fluid charging inlet 27. The vacuum pump valve is opened to evacuate the heat exchanger shell to a vacuum. Since an absolute vacuum is impossible, a small amount of non-condensable gas still exists when the pressure gauge shows 0 MPa. At this point, the working fluid tank valve is slightly opened to charge some working fluid gas. The working fluid tank valve is then closed, and the vacuum process continues. This operation is repeated three times to remove the non-condensable gas. Finally, the working fluid tank valve is fully opened, and the evaporation viewing window 8 is observed. The refrigerant completely submerges the evaporator heat exchange tubes 17, indicating that the working fluid charging is complete.

[0066] During the evaporation experiment, the temperature of the organic working medium is controlled by adjusting the temperature of the cold water circulation. During the condensation experiment, the temperature of the organic working medium is controlled by adjusting the temperature of the hot water circulation. When the temperature fluctuation is less than 0.1℃, it is considered that the water temperature is constant. If the saturation pressure and temperature of the organic working medium correspond, it indicates that there is no non-condensable gas in the condenser. The evaporation and condensation effect observed through the window is normal, the test bench is operating normally, the parameters within five minutes are recorded, and one set of test conditions is completed. The circulation water flow rate and temperature are adjusted to conduct the next set of test conditions.

[0067] The cooling circulation system includes an electric heating wire 22 and a condenser heat exchange tube 26; the condenser heat exchange tube 26 is installed inside the condenser shell 2 and is used to cool the steam; the electric heating wire 22 is used to control the temperature of the cooling water in the cooling circulation system within the target range.

[0068] like Figure 1As shown, the hot water circulation system includes an evaporator heat exchange tube 17, which is installed inside the evaporator shell 1 and used to heat the liquid. The outlet of the evaporator heat exchange tube 17 is connected sequentially along the water outlet direction to a first flow meter 12, a three-way valve 30, a plate heat exchanger 14, a hot water pump 9, and a hot water tank 15 via a pipeline. The outlet of the hot water tank 15, away from the hot water pump 9, is connected to the inlet of the evaporator heat exchange tube 17 via a pipeline. An electric heating element 10 is installed at the bottom of the hot water tank 15, and an exhaust valve 11 is installed at the top of the hot water tank 15. One end of the first heat exchange tube of the plate heat exchanger 14 is connected to the first flow meter 12 via a pipeline, and the other end... The water supply pump 13 is connected to the hot water pump 9 via a pipeline. The outlet of the water supply pump 13 has two branches: one branch connects to the second heat exchange tube of the plate heat exchanger 14 via a pipeline, and the other branch connects to the three-way valve 30. The inlet of the water supply pump 13 is connected to the cooling water tank 16 via a pipeline. The inlet of the cooling water tank 16 is connected to the second heat exchange tube of the plate heat exchanger 14 via a pipeline, and a straight-through valve 29 is installed on the pipeline. During use, the opening of the straight-through valve 29 is adjusted to control water supply and pressure regulation. The flow direction of the medium delivered by the water supply pump 13 is controlled by adjusting the valve core of the three-way valve 30.

[0069] In some embodiments, the second heat exchange tube of the plate heat exchanger 14 and the water supply pump 13 are both connected to the pipeline connecting the flow meter 12.

[0070] It should be noted that the electric heating element 10 has a power of 12kW, and the power can be adjusted as needed. The power can be adjusted according to the heat exchange load to heat the high-pressure water in the hot water tank 15 with small temperature fluctuations. The water supply pump 13, plate heat exchanger 14, and cooling water tank 16 are connected in sequence, and the water supply pump 13 is connected to the hot water circulation pipeline. When the heat exchange load is small, the power adjustment of the electric heating element 10 is lagging, and the operation of the water pump does work on the water, which will cause the water temperature to rise and cause water temperature fluctuations. At this time, the straight valve 29 can be opened, and the connection between the water supply pump 13 and the main pipeline (the pipeline where the flow meter 12 is located) can be closed through the three-way valve 30. The medium in the second heat exchange tube of the plate heat exchanger 14 and the first heat exchange tube can exchange heat, which plays a role in balancing excess heat. The water supply pump 13 has a head of 25m and is connected to the hot water circulation system. It starts when the medium temperature is too high. At this time, the three-way valve 30 is fully opened and the straight valve 29 is closed. The water supply pump 13 can supply water from the cooling water tank 16 into the pipeline where the flow meter 12 is located, thereby regulating the water temperature and pressure in the pipeline. It can play the role of constant pressure water supply and maintain the water temperature at 120℃ without boiling.

[0071] It should be further explained that a valve can be installed between the water supply pump 13 and the flow meter 12 to control the flow direction of the medium transported by the water supply pump 13.

[0072] In some embodiments, temperature sensors 5 are installed at both the inlet and outlet of the evaporation heat exchange tube 17 to detect the medium temperature at the inlet and outlet of the evaporation heat exchange tube 17.

[0073] like Figure 1 As shown, the cooling cycle system includes a refrigeration module and a water cooling module.

[0074] The water-cooling module includes an electric heating wire 22, a cold water tank 23, a cold water pump 24, a surface cooler 25, and a condenser heat exchange tube 26. The condenser heat exchange tube 26 is installed in the central region of the condenser shell 2 to cool the steam. The electric heating wire 22 is installed at the bottom of the cold water tank 23 to control the temperature of the cooling water in the cooling circulation system within a target range. Along the flow direction of the medium, the outlet of the condenser heat exchange tube 26 is connected sequentially to a second flow meter 12, the cold water tank 23, and the cold water pump 24 via pipelines. The outlet of the cold water pump 24, away from the cold water tank 23, is connected to the inlet of the condenser heat exchange tube 26 via a pipeline. The surface cooler 25 is laid on the pipeline at the inlet of the cold water tank 23, and the pipeline here can be bent in an S-shape. The refrigeration module is used for refrigeration and exchanges heat with the water-cooling module.

[0075] The refrigeration module, used for cooling and heat exchange with the water-cooling module, includes an evaporator coil 18, a throttling valve 19, a condenser coil 20, a compressor 21, and a chilled water tank 23. Specifically, the evaporator coil 18, compressor 21, and throttling valve 19 are connected sequentially along the direction of medium flow. The evaporator coil 18 is located inside the chilled water tank 23, with its inlet connected to the throttling valve 19 via a pipe, and its outlet connected to the compressor 21 via a pipe. The throttling valve 19 is located outside the chilled water tank 23. The compressor 21 is also located outside the chilled water tank 23. The condenser coil 20 is laid on the pipe between the throttling valve 19 and the compressor 21. Additionally, temperature sensors 5 are installed on the pipes at the inlet and outlet of the condenser heat exchanger tube 26.

[0076] It should be noted that the cooling module has a cooling power of 18kW, and the electric heating wire 22 has a power of 3kW for auxiliary heating. It can control the cold water circulation temperature between 0℃ and 80℃ and maintain it stably. When the cold water circulation temperature is below 40℃, the cooling module provides the cooling capacity; when the cold water circulation temperature is above 40℃, the compressor 21 system is shut down, and the cold water circulation relies on the surface cooler 25 of the water system for heat dissipation to maintain a stable cold water circulation temperature.

[0077] Evaporator shell 1 and condenser shell 2 are welded with threaded bases. Temperature sensor 5 and pressure sensor 6 are connected to these bases via threads of M20*1.5 with a probe insertion depth of 40mm to measure the saturation temperature of the organic working fluid on the shell side. Temperature sensor 5 is installed at the inlet and outlet of evaporator heat exchange tube 17 and condenser heat exchange tube 26 via internally threaded tees with an insertion depth of 10mm to measure the center temperature of the water circulation pipeline. The outputs of all sensors are displayed and recorded by a data acquisition instrument and stored in a computer. The overall heat transfer coefficient is calculated based on the measured temperature and flow rate, and the external heat transfer coefficient is obtained using the thermal resistance separation method.

[0078] The evaporator shell 1 and condenser shell 2 are sealed at both ends by flange plates. Two through holes are opened in the center of the flange plate of condenser shell 2, and two through holes are opened near the lower center of evaporator shell 1 to house two heat exchange tubes. The heat exchange tubes are secured with fasteners and O-rings. The heat exchange tubes are detachable for easy replacement with tubes of different tooth profiles. The condensing heat exchange tube 26 is located at the center of condenser shell 2, and the evaporating heat exchange tube 17 is located 30mm below the center of evaporator shell 1. The organic working fluid is charged halfway into evaporator shell 1 to submerge the evaporating heat exchange tube 17, reducing the amount of working fluid required. The heat exchange tubes are 1000mm long and 19mm in outer diameter to ensure effective heat exchange length.

[0079] like Figure 2 As shown, a test method applied to the above-mentioned high-temperature boiling and condensation heat exchanger outside the working fluid tube includes the following steps:

[0080] S1: The medium in the evaporation heat exchange tube 17 exchanges heat with the liquid in the evaporator shell 1, causing the liquid in the evaporator shell 1 to heat up and generate steam.

[0081] S2: During the steam rise process, the steam is introduced into the condenser shell 2 through the steam pipe 3.

[0082] S3: The medium in the condenser heat exchanger tube 26 is adjusted to the target temperature through the cooling circulation system, and the medium at the target temperature is exchanged with the steam to cool the steam and form a liquid.

[0083] S4: Under the action of gravity, the liquid is discharged to the evaporator shell 1 through the return pipe 4.

[0084] It should be noted that S1-S4 is a cycle. In S4, after the liquid enters the evaporator shell 1, the process of S1-S4 is repeated.

[0085] In some embodiments, S1 includes the following steps:

[0086] S101: The electric heating element 10 heats the medium in the hot water tank 15 and simultaneously discharges excess gas through the exhaust valve 11. After the medium is heated, it is transported to the evaporation heat exchange tube 17 by the hot water pump 9. If the medium temperature exceeds the target temperature, the passage between the three-way valve 30 and the water supply pump 13 is closed, and the straight-through valve 29 is opened, so that the water pumped by the water supply pump 13 passes through the second heat exchange tube of the plate heat exchanger 14 and exchanges heat with the medium in the first heat exchange tube, thereby stabilizing the temperature and keeping the medium temperature in the evaporation heat exchange tube 17 within the target range, ensuring that the water temperature reaches 120℃ without boiling. In addition, if the pressure of the medium is less than the target range, the straight-through valve 29 is closed, the three-way valve 30 is opened, and the water supply pump 13 delivers water from the cooling water tank 16 to the pipeline where the flow meter 12 is located, thereby replenishing water and restoring the pressure of the medium to the target range.

[0087] S102: The heated medium exchanges heat with the liquid in the evaporator shell 1 until the liquid is converted into steam.

[0088] Furthermore, S3 includes the following steps:

[0089] S301: The electric heating wire 22 assists in heating the medium inside the condenser heat exchange tube 26, while simultaneously enabling the refrigeration module in the cooling circulation system to exchange heat with the medium inside the condenser heat exchange tube 26 until the temperature of the medium inside the condenser heat exchange tube 26 is within the target range. Specifically, in the water-cooling module, the cold water pump 24 draws cold water from the cold water tank 23 into the condenser heat exchange tube 26, and the electric heating wire 22 assists in heating the cold water in the cold water tank 23, so that the temperature of the cold water circulation can be controlled and adjusted between 0℃ and 80℃ and maintained stably; at the same time, in the refrigeration module, the cooling medium continuously cools the circulating water through the evaporator coil 18. When the circulating water temperature is below 40℃, the compressor 21 provides cooling capacity; when the circulating water temperature is above 40℃, the refrigeration compressor 21 is turned off, and the cold water circulation relies on the surface cooler 25 of the water-cooling module for heat dissipation to maintain a stable cold water circulation temperature.

[0090] Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A heat exchange device for boiling and condensing a working fluid at a high temperature outside the tube, characterized in that, include: The working fluid circulation system includes an evaporator shell (1) and a condenser shell (2) with a height difference. The evaporator shell (1) is located below the condenser shell (2). A steam pipe (3) and a return pipe (4) are connected between the evaporator shell (1) and the condenser shell (2). The cooling circulation system includes an electric heating wire (22) and a condenser heat exchange tube (26); the condenser heat exchange tube (26) is installed in the middle region inside the condenser housing (2); the electric heating wire (22) is located at the bottom of the cooling circulation system; The hot water circulation system includes an evaporation heat exchange tube (17) installed inside the evaporator shell (1).

2. The working fluid external high-temperature boiling and condensation heat exchanger according to claim 1, characterized in that, In the working fluid circulation system, several temperature sensors (5) are installed on the upper and lower surfaces of the evaporator shell (1), and a pressure sensor (6) is installed at the center of the upper surface to obtain pressure and temperature data of the evaporator shell (1) in real time. Several temperature sensors (5) are installed on the upper surface of the condenser housing (2), and a pressure sensor (6) is installed at the center of the upper surface to obtain pressure and temperature data of the condenser housing (2) in real time.

3. The working fluid external high-temperature boiling and condensation heat exchange device according to claim 1, characterized in that, In the working fluid circulation system, an evaporation window (8) is also installed on the surface of the evaporator shell (1) at the position corresponding to the evaporation heat exchange tube (17). The evaporation window (8) is used to observe the evaporation heat exchange tube (17) inside the evaporator shell (1). A condensing window (7) is installed on the surface of the condenser shell (2) at the position corresponding to the condensing heat exchange tube (26). The condensing window (7) is used to observe the condensing heat exchange tube (26) inside the condenser shell (2).

4. The working fluid external high-temperature boiling and condensation heat exchange device according to claim 1, characterized in that, In the working fluid circulation system, an organic working fluid extraction port (28) is provided on one side of the lower surface of the evaporator shell (1), and an organic working fluid charging port (27) is provided on the same side of the upper surface of the condenser shell (2).

5. The working fluid external high-temperature boiling and condensation heat exchange device according to claim 1, characterized in that, In a hot water circulation system, the following are included: The outlet of the evaporative heat exchange tube (17) is connected in sequence to the first flow meter (12), three-way valve (30), plate heat exchanger (14), hot water pump (9) and hot water tank (15) along the water outlet direction; The outlet of the hot water tank (15) away from the hot water pump (9) is connected to the inlet of the evaporative heat exchange tube (17) through a pipeline; An electric heating element (10) is installed at the bottom of the hot water tank (15); An exhaust valve (11) is installed on top of the hot water tank (15); One end of the first heat exchange tube of the plate heat exchanger (14) is connected to the first flow meter (12) through a pipeline, and the other end is connected to the hot water pump (9) through a pipeline; The water supply pump (13) has two branches at its outlet. One branch is connected to the second heat exchange tube of the plate heat exchanger (14) through a pipeline, and the other branch is connected to the three-way valve (30). The inlet of the water supply pump (13) is connected to the cooling water tank (16) through a pipeline. The inlet of the cooling water tank (16) is connected to the second heat exchange tube of the plate heat exchanger (14) through a pipeline, and a straight valve (29) is installed on the pipeline; Temperature sensors (5) are installed at both the inlet and outlet of the evaporative heat exchange tube (17).

6. The working fluid external high-temperature boiling and condensation heat exchange device according to claim 5, characterized in that, In the hot water circulation system, the second heat exchange tube of the plate heat exchanger (14) and the water supply pump (13) are both connected to the pipeline connecting the flow meter (12).

7. The working fluid external high-temperature boiling and condensation heat exchanger according to claim 5, characterized in that, The cooling cycle system includes a refrigeration module and a water cooling module. In the water cooling module, along the direction of medium flow, the outlet of the condensing heat exchange tube (26) is connected in sequence to a second flow meter (12), a cold water tank (23), and a cold water pump (24) through a pipeline. Temperature sensors (5) are installed on the pipelines at the inlet and outlet positions of the condensing heat exchange tube (26). The electric heating wire (22) is installed at the bottom of the cold water tank (23); The outlet of the cold water pump (24) away from the cold water tank (23) is connected to the inlet of the condenser heat exchange tube (26) through a pipeline; A surface cooler (25) is laid on the pipe at the inlet of the cold water tank (23); The refrigeration module is used for refrigeration and heat exchange with the water-cooling module.

8. The working fluid external high-temperature boiling and condensation heat exchange device according to claim 7, characterized in that, In the refrigeration module, an evaporator coil (18), a compressor (21), and a throttle valve (19) are connected sequentially along the direction of medium flow. The evaporator coil (18) is located inside the cold water tank (23), with the inlet connected to a throttle valve (19) via a pipe and the outlet connected to a compressor (21) via a pipe. The throttle valve (19) is located outside the cold water tank (23); The compressor (21) is located outside the cold water tank (23); A condenser coil (20) is laid on the pipe between the throttle valve (19) and the compressor (21).

9. A test method applied to a high-temperature boiling and condensation heat exchanger for a working fluid outside a tube as described in any one of claims 5-8, characterized in that, Includes the following steps: The medium in the evaporation heat exchange tube (17) exchanges heat with the liquid in the evaporator shell (1), thereby raising the temperature of the liquid in the evaporator shell (1) to generate steam. During the steam rise process, the steam is introduced into the condenser shell (2) through the steam pipe (3); The medium in the condenser heat exchange tube (26) is adjusted to the target temperature by the cooling circulation system, and the medium at the target temperature is exchanged with the steam to cool the steam and form a liquid. Under the influence of gravity, the liquid is discharged to the evaporator shell (1) through the return pipe (4).

10. The test method according to claim 9, characterized in that, The heat exchange between the medium in the evaporator heat exchange tube (17) and the liquid in the evaporator shell (1) includes the following steps: The medium in the evaporative heat exchange tube (17) is heated by a hot water circulation system. If the medium temperature exceeds the target range, heat exchange is performed to cool it down until the medium temperature in the evaporative heat exchange tube (17) is within the target range. If the medium pressure is less than the target range, water is added by a water pump (13) to bring the medium pressure within the target range. The heated medium exchanges heat with the liquid in the evaporator shell (1) until the liquid is converted into steam.

11. The test method according to claim 9, characterized in that, Adjusting the medium in the condenser heat exchanger tube (26) to the target temperature via the cooling circulation system includes the following steps: The electric heating wire (22) assists in heating the medium in the condensing heat exchange tube (26), while the refrigeration module in the cooling cycle system exchanges heat with the medium in the condensing heat exchange tube (26) until the temperature of the medium in the condensing heat exchange tube (26) is within the target range.

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