A heat shock flash evaporation loop flow ascending heat exchange test system and test method

Abstract

The present application relates to a kind of heat shock flash evaporation loop lift membrane heat exchange test system, including heat exchange pipe, vapor-liquid separator, condenser, metering barrel, vacuum pump, liquid tank, heat shock heater, throttle valve, measurement and control system and high-speed camera, the upper outlet of heat exchange pipe is connected with the import of vapor-liquid separator, the secondary steam outlet of vapor-liquid separator is connected with the hot medium side import of condenser, the hot medium side outlet of condenser is connected with metering barrel and liquid tank respectively, the concentrated liquid outlet of vapor-liquid separator is connected with liquid tank, the outlet of metering barrel is connected with liquid tank, vacuum pump is connected with liquid tank, liquid tank is connected with heat shock heater, heat shock heater is connected with heat exchange pipe, throttle valve is arranged between heat shock heater and heat exchange pipe;High-speed camera is arranged in one side of heat exchange pipe.The present application can realize the experimental test to heat shock flash evaporation loop lift membrane heat exchange technology, and provide support for mechanism research, equipment optimization of heat shock flash evaporation loop lift membrane heat exchange technology.

Description

Technical Field

[0001] This invention relates to the field of rising film heat transfer technology, specifically to a thermally excited flash evaporation circulating rising film heat transfer test system and test method. Background Technology

[0002] Rising film heat transfer, as a highly efficient vapor-liquid two-phase heat transfer method, is widely used in chemical equipment such as evaporators and reboilers. Its core principle is to utilize the drag effect of the vapor phase to form a continuous liquid film along the heat exchange tube wall, achieving efficient phase change heat transfer. Annular flow is considered the optimal flow pattern for rising film heat transfer, characterized by a thin vapor-liquid film, stable flow, and the highest heat transfer efficiency. Thermally stimulated flash circulating rising film heat transfer is a novel technology that involves rapidly increasing the pressure and energy storage of the feed liquid, followed by isenthalpic throttling flash evaporation. The vapor-liquid two-phase flow generated by the throttling directly drives the flow pattern within the heat exchange tube to form a highly efficient annular flow. Because this technology is emerging, there is currently no dedicated testing system for it; conventional rising film heat transfer testing systems can only perform tests on ordinary rising film heat transfer processes.

[0003] For example, Chinese patent CN109855900A discloses a comprehensive testing system for a rising film evaporator, which consists of a cooling medium pipeline unit, a steam pipeline unit, a test heat exchanger unit, and a data measurement and control unit. In the cooling medium pipeline unit, the centrifugal pump inlet is connected to the heating water tank outlet via a threaded ball valve and a Y-type filter; the centrifugal pump outlet is connected to a first parallel pipeline, and a regulating valve controls the flow rate of the first parallel pipeline, allowing the cooling medium to flow through a second parallel pipeline into the tube-side inlet of the main heat exchanger under test. After heat exchange, the medium finally flows back into the heating water tank via a small heat exchanger at the top, forming the cooling medium pipeline unit. The steam pipeline unit includes a steam generator, a pressure stabilizing tank, a steam regulating valve, a vortex flow meter, a condensate tank, various valves, and connecting pipes. In the steam pipeline unit, the steam generator is connected sequentially to a pressure tank, a steam regulating valve, and a vortex flow meter via pipelines. Heating steam is then delivered to the shell-side inlet of the main heat exchanger via a third parallel pipeline. After heat exchange, the steam condenses into liquid and flows into a condensate tank via a fourth parallel pipeline. The condensate is then discharged through a drain pipe via a steam trap, thus forming the steam pipeline unit. The test heat exchanger unit includes a main heat exchanger, a first gas-liquid separator, a second gas-liquid separator, a first plate heat exchanger, a second plate heat exchanger, and connecting pipelines. The main heat exchanger consists of a rising film shell-and-tube heat exchanger and a falling film shell-and-tube heat exchanger, which are connected to the corresponding gas-liquid separators and plate heat exchangers via pipelines to complete the heat exchange process of the hot and cold media and the gas-liquid separation process of the cold media.

[0004] It is known that the small heat exchanger in the aforementioned prior art is set up to supplement the heat of the material in the rising film shell-and-tube heat exchanger. Its temperature is at most the evaporation temperature and will not exceed the evaporation temperature. The regulating valve is only set to control the flow rate of the first parallel pipeline. However, the principle of thermally stimulated flash evaporation circulating rising film heat exchange is to rapidly heat and pressurize the material through a thermally stimulated heat exchanger. The temperature after heating and pressurization is higher than the evaporation temperature. Then, the material is throttled and depressurized through a throttling valve for flash evaporation. The vapor-liquid two-phase flow after flash evaporation can drive the flow pattern in the heat exchange tube to directly form a highly efficient circulating flow. Therefore, the comprehensive test system for rising film evaporators in the aforementioned prior art cannot meet the performance testing requirements of thermally stimulated flash evaporation circulating rising film technology, nor can it obtain accurate experimental data related to this technology. Summary of the Invention

[0005] The present invention aims to provide a thermally stimulated flash evaporation circulating rising film heat transfer testing system and testing method to overcome the shortcomings of the prior art. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0006] A thermally stimulated flash evaporation circulating rising film heat exchange testing system includes heat exchange tubes, a vapor-liquid separator, a condenser, a metering tank, a vacuum pump, a storage tank, a thermally stimulated heater, a throttling valve, a monitoring and control system, and a high-speed camera. The upper outlet of the heat exchange tubes is connected to the inlet of the vapor-liquid separator. The secondary vapor outlet of the vapor-liquid separator is connected to the hot medium side inlet of the condenser. The hot medium side outlet of the condenser is connected to both the metering tank and the storage tank. The concentrated liquid outlet of the vapor-liquid separator is connected to the storage tank. The outlet of the metering tank is connected to the storage tank. The condenser is connected to the metering tank. A shut-off valve is provided between the condenser and the storage tank, and between the metering tank and the storage tank. The vacuum pump is connected to the storage tank. The outlet of the storage tank is connected to the inlet of the cold medium flow channel of the heat shock heater. The outlet of the cold medium flow channel of the heat shock heater is connected to the inlet of the heat exchange tube. A throttling valve is provided between the heat shock heater and the heat exchange tube. The measurement and control system is used to collect parameter data of designated nodes and adjust the parameters of each node. A high-speed camera is provided on one side of the heat exchange tube to capture the evolution process of the rising film flow pattern in the heat exchange tube.

[0007] Preferably, the outlet of the cold medium flow channel of the heat shock heater is connected to the liquid storage tank, and a shut-off valve is provided between the outlet of the cold medium flow channel of the heat shock heater and the liquid storage tank.

[0008] Preferably, the heat exchange tube is a transparent glass jacketed tube.

[0009] Preferably, the upper opening of the jacket of the heat exchange tube is connected to the return port of the thermal oil pot, the lower opening of the jacket of the heat exchange tube is connected to the outlet of the thermal oil pump, and the inlet of the thermal oil pump is connected to the outlet of the thermal oil pot.

[0010] Preferably, the heat exchange tube is a CVD-coated quartz tube.

[0011] Preferably, a shut-off valve is provided between the vacuum pump and the liquid storage tank.

[0012] Preferably, the measurement and control system includes a temperature sensor, a pressure sensor, and a flow sensor disposed between the thermal heater and the throttle valve, a temperature sensor, a pressure sensor, and a flow sensor disposed between the throttle valve and the heat exchange tube, a temperature sensor and a pressure sensor disposed between the vapor-liquid separator and the condenser, and a temperature sensor and a flow sensor disposed between the vapor-liquid separator and the liquid storage tank.

[0013] Preferably, the device also includes an air compressor, the air inlet of which is connected to the inlet of the heat exchange tube, and a flow regulating valve and a flow sensor are provided between the air compressor and the heat exchange tube.

[0014] Preferably, a circulation pump is provided between the liquid storage tank and the heat shock heater.

[0015] A test method based on a thermal flash evaporation circulating rising film heat transfer test system as described above includes the following steps: S1, Cold Model Test: Using water-air as the medium, the vapor-liquid ratio at the inlet of the heat exchange tube is adjusted. The rising film flow pattern in the heat exchange tube under each vapor-liquid ratio is recorded and compared by a high-speed camera. The critical vapor-liquid volume ratio range at the inlet when the heat exchange tube transitions to liquid flow, bubbly flow, slug flow, mixed flow, annular flow, and mist flow is determined, providing basic data for subsequent tests. S2, Thermal shock flash evaporation rising film test; using water as the medium, the effect of the inlet vapor-liquid ratio of the heat exchange tube on the rising film flow pattern inside the tube is determined by adjusting the parameters of thermal shock and flash evaporation; the parameters to be adjusted for thermal shock and flash evaporation include thermal shock completion temperature, throttling pressure, liquid supply rate, and evaporation temperature; by observing and recording the correlation between the flow pattern inside the heat exchange tube and the inlet vapor-liquid ratio, the parameter range of the circulating rising film is determined; S3, Performance test of the thermal flash evaporation rising film system; Adjust the thermal excitation completion temperature and the opening of the throttle valve to ensure that the liquid in the heat exchange tube is in a stable circulating rising film operation state. After stable operation for a period of time, switch the outlet of the heat medium side in the condenser to be connected only to the metering tank, so as to measure the amount of liquid evaporation within a fixed time. Calculate and determine the rising film heat transfer coefficient based on the amount of liquid evaporation, latent heat of liquid, heat transfer temperature difference, and effective heat transfer area parameters of the heat exchange tube. S4, Data Processing and Analysis: Using data collected by the measurement and control system and video recordings of the flow pattern of the liquid in the heat exchange tubes by high-speed cameras, calculate parameters such as the inlet vapor-liquid ratio, gas holdup, rising film heat transfer coefficient, Reynolds number, apparent vapor velocity, and apparent liquid velocity of the heat exchange tubes. Summarize the influence of parameters such as the inlet vapor-liquid ratio, throttling pressure, heat quenching temperature, heat flux density, and heat transfer temperature difference on the formation of the circulating rising film and heat transfer performance, and establish a mathematical model for heat quenching flash evaporation circulating rising film heat transfer.

[0016] The thermal flash evaporation circulating rising film heat transfer testing system and method provided by this invention have the following beneficial effects: The testing system in this invention integrates a cold model and a thermal flash evaporation rising film testing unit. Combined with a measurement and control system and high-speed camera equipment, it can complete the entire process testing, including vapor-liquid ratio control, superheated water flash evaporation, and pipe throttling. It can accurately collect multi-dimensional parameters and record the evolution of the flow pattern within the pipe. Through step-by-step operations—cold model testing, thermal flash evaporation rising film testing, system performance testing, and data comparison and analysis—this invention verifies the promoting effect of thermal flash evaporation on the formation of circulating rising film. It accurately measures key parameters such as the critical vapor-liquid volume ratio and rising film heat transfer coefficient for different flow patterns. By summarizing the influence of these parameters and constructing a matching model, it provides precise experimental testing support for the mechanism research and equipment design optimization of thermal flash circulating rising film heat transfer technology. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the heat exchange tube structure in one embodiment of the present invention; Figure 3 This is a schematic diagram of another embodiment of the present invention; Figure 4 This is a schematic diagram of the heat exchange tube in another embodiment of the present invention.

[0018] The reference numerals in the attached figures are, in order: 1. heat exchange tube, 2. vapor-liquid separator, 3. condenser, 4. metering tank, 5. vacuum pump, 6. liquid storage tank, 7. circulating pump, 8. heat shock heater, 9. throttle valve, 10. thermal oil pump, 11. thermal oil pan, 12. measurement and control system, 13. high-speed camera, 14. air compressor. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] Example 1: Reference Figure 1As shown, a thermally stimulated flash evaporation circulating rising film heat exchange testing system is improved in that it includes a heat exchange tube 1, a vapor-liquid separator 2, a condenser 3, a metering tank 4, a vacuum pump 5, a storage tank 6, a thermally stimulated heater 8, a throttling valve 9, a measurement and control system 12, and a high-speed camera 13. The upper outlet of the heat exchange tube 1 is connected to the inlet of the vapor-liquid separator 2. The secondary vapor outlet of the vapor-liquid separator 2 is connected to the hot medium side inlet of the condenser 3. The hot medium side outlet of the condenser 3 is connected to both the metering tank 4 and the storage tank 6. The concentrated liquid outlet of the vapor-liquid separator 2 is connected to the storage tank 6. The outlet of the metering tank 4 is connected to the storage tank 6. The condenser... A shut-off valve is provided between the condenser 3 and the metering tank 4, between the condenser 3 and the storage tank 6, and between the metering tank 4 and the storage tank 6. The vacuum pump 5 is connected to the storage tank 6. The outlet of the storage tank 6 is connected to the inlet of the cold medium flow channel of the heat-stimulating heater 8. The outlet of the cold medium flow channel of the heat-stimulating heater 8 is connected to the inlet of the heat exchange tube 1. The throttling valve 9 is provided between the heat-stimulating heater 8 and the heat exchange tube 1. The measurement and control system 12 is used to collect parameter data of designated nodes and adjust the parameters of each node. The high-speed camera 13 is provided on one side of the heat exchange tube 1 and is used to capture the evolution process of the rising film flow pattern in the heat exchange tube 1.

[0021] In this embodiment, the vapor-liquid separator 2 is used to separate the vapor-liquid mixture at the outlet of the heat exchange tube 1 to avoid vapor-liquid entrainment affecting the accuracy of evaporation measurement.

[0022] Furthermore, the vapor-liquid separator 2 is a gravity separation type vapor-liquid separator with a cylindrical structure, a non-condensable gas discharge port at the top, a secondary steam outlet on the upper side wall, and an inlet and a concentrate outlet at the bottom.

[0023] The function of condenser 3 is to cool and condense the secondary steam evaporated by heat exchange tube 1, so as to facilitate the measurement of condensate evaporation by heat exchange tube 1.

[0024] Furthermore, the condenser 3 adopts one of the following heat exchangers: shell and tube, plate, or coaxial.

[0025] The metering tank 4 is used to perform cumulative metering of the evaporation condensate of the heat exchange tube 1, and to calculate the heat exchange capacity of the heat exchange tube 1 by measuring the amount of liquid evaporation and the latent heat of the liquid.

[0026] Furthermore, the measuring barrel 4 is a cylindrical glass cylinder with a standard inner diameter and volume scale lines on the side wall.

[0027] Vacuum pump 5 is used to regulate the vacuum level of the system, which facilitates the adjustment of the evaporation temperature by adjusting the gas pressure.

[0028] Furthermore, the vacuum pump 5 is a water ring vacuum pump or a screw vacuum pump.

[0029] The heat shock heater 8 is used to heat the liquid material at high temperature. Further, the heat shock heater 8 is an electric heater or a wall-mounted heater, with the heat source for the wall-mounted heater being high-temperature live steam or heat transfer oil.

[0030] Throttling valve 9 is used to throttle and reduce the pressure of the liquid after thermal shock, so that the liquid will be depressurized and flash evaporated to produce a rapidly expanding vapor-liquid mixture.

[0031] Furthermore, the throttle valve 9 is a manual throttle valve, an electric throttle valve, or a thermal throttle valve.

[0032] The high-speed camera 13 is used to capture the rising film flow pattern inside the heat exchange tube 1 and record and compare the evolution of the rising film flow pattern inside the heat exchange tube 1 under different experimental parameter conditions.

[0033] Furthermore, the cold medium flow channel outlet of the heat shock heater 8 is connected to the liquid storage tank 6 to facilitate heating of the liquid in the liquid storage tank 6 during the initial stage of the heat shock flash film test. A shut-off valve is provided between the cold medium flow channel outlet of the heat shock heater 8 and the liquid storage tank 6.

[0034] Furthermore, a shut-off valve is provided between the vacuum pump 5 and the liquid storage tank 6.

[0035] Furthermore, the measurement and control system 12 includes a temperature sensor, a pressure sensor, and a flow sensor disposed between the thermal heater 8 and the throttle valve 9, a temperature sensor, a pressure sensor, and a flow sensor disposed between the throttle valve 9 and the heat exchange tube 1, a temperature sensor and a pressure sensor disposed between the vapor-liquid separator 2 and the condenser 3, and a temperature sensor and a flow sensor disposed between the vapor-liquid separator 2 and the liquid storage tank 6.

[0036] Furthermore, the measurement and control system 12 includes a programmable controller.

[0037] In this embodiment, various sensors are used to collect raw data such as temperature, pressure, flow rate, and heating power of the system, thereby calculating and determining key parameters of the test system such as heat transfer temperature difference, heat load, vapor-liquid ratio (mass) after throttling, gas holdup (volume) after throttling, throttling pressure drop, throttling temperature drop, heat transfer coefficient, rising film Reynolds number, apparent vapor velocity in the pipe, and apparent liquid velocity in the pipe; together with the shut-off valve, circulating pump, and vacuum pump, the precise control of parameters such as throttling pressure, thermal shock temperature, circulating flow rate, and operating vacuum degree is achieved.

[0038] Furthermore, the system also includes an air compressor 14, the air inlet of which is connected to the inlet of the heat exchange tube 1. A flow regulating valve and a flow sensor are installed between the air compressor 14 and the heat exchange tube 1. The air compressor 14 is used to provide compressed air to the system during cold mold experiments.

[0039] Furthermore, a circulation pump 7 is provided between the liquid storage tank 6 and the heat shock heater 8.

[0040] The circulating pump 7 is used to pressurize the liquid in the storage tank 6 to prevent vaporization during the thermal shock heating process. Furthermore, the circulating pump 7 adopts variable frequency speed control to facilitate the regulation of the system's circulating flow rate.

[0041] Furthermore, temperature sensors are equidistantly attached to the outer wall of the heat exchange tube 1.

[0042] Example 2: A test method based on a thermal flash evaporation circulating rising film heat transfer test system as described in Example 1, the improvement of which includes the following steps: S1, Cold Model Test: Using water-air as the medium, the vapor-liquid ratio at the inlet of heat exchange tube 1 is adjusted. The rising film flow pattern in heat exchange tube 1 under various vapor-liquid ratios is recorded and compared by high-speed camera 13. The critical vapor-liquid volume ratio range at the inlet when the flow changes from liquid phase flow, bubbly flow, slug flow, turbulent flow, annular flow, to mist flow in heat exchange tube 1 is determined to provide basic data for subsequent tests. At this time, the thermal shock heater 8 is not working and is only used as a passage. Heat exchange tube 1 is not heated, and the flow regulating valve between air compressor 14 and heat exchange tube 1 is in the open state. S2, Thermal shock flash film riser test; using water as the medium, the effect of the inlet vapor-liquid ratio of heat exchange tube 1 on the flow pattern of the rising film inside the tube is determined by adjusting the parameters of thermal shock and flash evaporation; the parameters to be adjusted for thermal shock and flash evaporation include thermal shock completion temperature, throttling pressure, liquid supply rate, and evaporation temperature; by observing and recording the correlation between the flow pattern inside heat exchange tube 1 and the inlet vapor-liquid ratio, the parameter range of the circulating rising film is determined; at this time, the shut-off valves between condenser 3 and liquid storage tank 6, between condenser 3 and metering tank 4, and between metering tank 4 and liquid storage tank 6 are all in the open state. At this time, metering tank 4 is only used as a section of pipeline, thermal shock heater 8 is working normally, and the flow regulating valve between air compressor 14 and heat exchange tube 1 is closed; S3, Performance test of the thermal flash evaporation rising film system; Adjust the thermal excitation completion temperature and the opening of the throttle valve 9 to ensure that the liquid in the heat exchange tube 1 is in a stable circulating rising film operation state. After stable operation for a period of time, switch the outlet of the heat medium side in the condenser 3 to be connected only to the metering tank 4. That is, the shut-off valve between the condenser 3 and the metering tank 4 is opened, the shut-off valve between the condenser 3 and the storage tank 6 is closed, and the shut-off valve between the metering tank 4 and the storage tank 6 is closed, so as to measure the amount of liquid evaporation within a fixed time. Based on the amount of liquid evaporation, the latent heat of the liquid, the heat transfer temperature difference, and the effective heat transfer area parameters of the heat exchange tube, calculate and determine the rising film heat transfer coefficient. S4, Data Processing and Analysis: Using data collected by the measurement and control system 12 and video recordings of the flow pattern of the liquid in the heat exchange tube 1 by the high-speed camera 13, calculate parameters such as the inlet vapor-liquid ratio, gas holdup, rising film heat transfer coefficient, Reynolds number, apparent vapor velocity, and apparent liquid velocity of the heat exchange tube 1. Summarize the influence of parameters such as the inlet vapor-liquid ratio, throttling pressure, thermal shock temperature, heat flux density, and heat transfer temperature difference on the formation of the circulating rising film and heat transfer performance, and establish a mathematical model for thermally stimulated flash evaporation circulating rising film heat transfer.

[0043] The testing system in this embodiment integrates the testing functions of cold model and thermal flash evaporation rising film system. Equipped with a dedicated measurement and control system and high-speed camera equipment, it can complete tests on the inlet vapor-liquid ratio of the heat exchange tubes, the thermal flash evaporation of the feed liquid, and the heat transfer performance of the rising film circulation in the thermal flash evaporation circulating film system. Furthermore, it can achieve visualized research on the rising film flow pattern within the heat exchange tubes under different parameter matching conditions. This testing system provides accurate experimental data and testing support for the mechanism research and equipment design optimization of thermal flash evaporation circulating film heat transfer technology.

[0044] Example 3: Based on Example 1 or 2, refer to Figure 1 and Figure 2 As shown, the heat exchange tube 1 is a transparent glass jacketed tube with an inner diameter of 19 mm, a jacket diameter of 32 mm, and a length of 2000 mm. The lower end of the jacket of the heat exchange tube 1 is connected to the outlet of the thermal oil pump 10, and the upper end of the jacket is connected to the return port of the thermal oil pot 11. The thermal oil pot adopts a programmed temperature control method to control and adjust the heat transfer temperature difference of the heat exchange tube. Temperature sensors are attached at equal intervals to the outer wall of the heat exchange tube 1.

[0045] The vapor-liquid separator 2 adopts a gravity-separated cylindrical structure with a diameter of 200 mm and a height of 400 mm. The top of the separator has a non-condensable gas outlet, the upper side wall has a secondary steam outlet, and the bottom has a heat exchange tube inlet and a concentrated liquid outlet. The condenser 3 is a plate heat exchanger with an area of ​​0.5 m². 2The metering cylinder 4 is a glass cylinder with an inner diameter of 100mm and a height of 400mm, and the side wall of the metering cylinder has volume graduation lines; the vacuum pump 5 is a water ring vacuum pump; the circulation pump 7 is used to pressurize the liquid in the storage tank to prevent the liquid from vaporizing during the heat shock heating process; the circulation pump 7 is a variable frequency centrifugal pump with a flow rate of 500L / h and a head of 32m; the function of the heat shock heater 8 is to heat the test liquid at high temperature. In this embodiment, the heat shock heater is a power adjustable pipeline electric heater with a heating power of 5kW; the function of the throttle valve 9 is to throttle and reduce the pressure of the liquid after heat shock heating, so that the liquid will generate a rapidly expanding vapor-liquid mixture after depressurization and flash evaporation; the throttle valve 9 is a manual throttle valve; the air compressor 14 is used to provide compressed air to the system during the cold model experiment.

[0046] Example 4: Based on Example 1 or 2, refer to Figure 3 As shown, the heat exchange tube 1 is a CVD-coated quartz tube. The structure of the CVD-coated quartz tube is shown in the figure. Figure 4 As shown, the CVD (Chemical Vapor Deposition) coated quartz tube involves preparing an extremely thin and dense conductive film on the outer wall of a high-purity quartz tube. This extremely thin conductive film does not affect the light transmittance of the quartz tube and does not interfere with the high-speed camera's recording of the rising film flow pattern within the heat exchange tube. An adjustable voltage is applied to the conductive film on the outer wall via a voltage regulator. The resistive properties of the conductive film generate Joule heating, which is directly transferred to the inner wall of the quartz tube via heat conduction, achieving direct heating of the liquid inside the tube. The input voltage can be precisely adjusted via the voltage regulator to change the heating power. In this embodiment, the CVD coated quartz tube has an inner diameter of 19 mm, a height of 2000 mm, and a heating power range of 0~3.7 kW.

[0047] In this embodiment, the heat exchange tube is a CVD-coated quartz tube. Compared with the indirect heating method of glass-jacketed heat exchange tubes, the heating power and heating temperature of CVD-coated quartz tubes are more convenient and faster to control. In addition, the CVD coating layer does not affect the light transmittance of the quartz tube, providing a clear visualization window for high-speed cameras to observe the rising film flow pattern inside the heat exchange tube, avoiding the problem of the field of view being affected by factors such as steam condensation in the jacketed tube.

[0048] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments described in this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0051] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0052] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0053] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thermally stimulated flash evaporation circulating rising film heat transfer testing system, characterized in that: The system includes a heat exchange tube (1), a vapor-liquid separator (2), a condenser (3), a metering tank (4), a vacuum pump (5), a storage tank (6), a heat-induced heater (8), a throttle valve (9), a monitoring and control system (12), and a high-speed camera (13). The upper outlet of the heat exchange tube (1) is connected to the inlet of the vapor-liquid separator (2). The secondary steam outlet of the vapor-liquid separator (2) is connected to the heat medium side inlet of the condenser (3). The heat medium side outlet of the condenser (3) is connected to the metering tank (4) and the storage tank (6) respectively. The concentrated liquid outlet of the vapor-liquid separator (2) is connected to the storage tank (6). The outlet of the metering tank (4) is connected to the storage tank (6). The condenser (3) is connected to the metering tank (4). A shut-off valve is provided between the condenser (3) and the liquid storage tank (6), and between the metering tank (4) and the liquid storage tank (6). The vacuum pump (5) is connected to the liquid storage tank (6). The outlet of the liquid storage tank (6) is connected to the inlet of the cold medium flow channel of the heat shock heater (8). The outlet of the cold medium flow channel of the heat shock heater (8) is connected to the inlet of the heat exchange tube (1). The throttle valve (9) is provided between the heat shock heater (8) and the heat exchange tube (1). The measurement and control system (12) is used to collect parameter data of designated nodes and adjust the parameters of each node. The high-speed camera (13) is provided on one side of the heat exchange tube (1) and is used to film the evolution process of the rising film flow pattern in the heat exchange tube (1).

2. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: The outlet of the cold medium flow channel of the heat shock heater (8) is connected to the liquid storage tank (6), and a shut-off valve is provided between the outlet of the cold medium flow channel of the heat shock heater (8) and the liquid storage tank (6).

3. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: The heat exchange tube (1) is a transparent glass jacketed tube.

4. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 3, characterized in that: The upper opening of the jacket of the heat exchange tube (1) is connected to the return port of the heat transfer oil pot (11), the lower opening of the jacket of the heat exchange tube (1) is connected to the outlet of the heat transfer oil pump (10), and the inlet of the heat transfer oil pump (10) is connected to the outlet of the heat transfer oil pot (11).

5. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: The heat exchange tube (1) is a CVD coated quartz tube.

6. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: A shut-off valve is provided between the vacuum pump (5) and the liquid storage tank (6).

7. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: The measurement and control system (12) includes a temperature sensor, a pressure sensor, and a flow sensor disposed between the heat-induced heater (8) and the throttle valve (9), a temperature sensor, a pressure sensor, and a flow sensor disposed between the throttle valve (9) and the heat exchange tube (1), a temperature sensor and a pressure sensor disposed between the vapor-liquid separator (2) and the condenser (3), and a temperature sensor and a flow sensor disposed between the vapor-liquid separator (2) and the liquid storage tank (6).

8. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: It also includes an air compressor (14), the air inlet of which is connected to the inlet of the heat exchange tube (1), and a flow regulating valve and a flow sensor are provided between the air compressor (14) and the heat exchange tube (1).

9. The thermal flash evaporation circulating rising film heat transfer testing system according to claim 1, characterized in that: A circulation pump (7) is provided between the liquid storage tank (6) and the heat shock heater (8).

10. A test method based on a thermally stimulated flash evaporation circulating rising film heat transfer test system as described in any one of claims 1-9, characterized in that: Includes the following steps: S1, cold model test; using water-air as the medium, adjust the vapor-liquid ratio at the inlet of the heat exchange tube (1), record and compare the rising film flow pattern in the heat exchange tube (1) under each vapor-liquid ratio using a high-speed camera (13), and determine the critical vapor-liquid volume ratio range at the inlet when the liquid phase flow, bubble flow, slug flow, mixed flow, annular flow and mist flow change in the heat exchange tube (1), so as to provide basic data for subsequent tests; S2, Thermal shock flash film riser test; using water as the medium, by adjusting the parameters of thermal shock and flash evaporation, the effect of the inlet vapor-liquid ratio of the heat exchange tube (1) on the flow pattern of the rising film inside the tube is determined; the parameters of thermal shock and flash evaporation that need to be adjusted include thermal shock completion temperature, throttling pressure, liquid supply, and evaporation temperature; by observing and recording the correlation between the flow pattern inside the heat exchange tube (1) and the inlet vapor-liquid ratio, the parameter range of the circulating rising film is determined; S3, Performance test of the thermal flash evaporation rising film system; Adjust the thermal excitation completion temperature and the opening of the throttle valve (9) to ensure that the liquid in the heat exchange tube (1) is in a stable circulating rising film operation state. After a period of stable operation, switch the outlet of the heat medium side in the condenser (3) to only connect with the metering tank (4) to measure the amount of liquid evaporation within a fixed time. Calculate and determine the rising film heat transfer coefficient based on the amount of liquid evaporation, the latent heat of the liquid, the heat transfer temperature difference, and the effective heat transfer area parameters of the heat exchange tube. S4, Data Processing and Analysis: Using the data collected by the measurement and control system (12) and the video of the flow pattern of the liquid in the heat exchange tube (1) recorded by the high-speed camera (13), calculate the parameters such as the inlet vapor-liquid ratio, gas holdup, rising film heat transfer coefficient, Reynolds number, apparent vapor velocity, and apparent liquid velocity of the heat exchange tube (1), summarize the influence of parameters such as the inlet vapor-liquid ratio, throttling pressure, heat shock temperature, heat flux density, and heat transfer temperature difference on the formation of the circulating rising film and the heat transfer performance, and establish a mathematical model of heat shock flash evaporation circulating rising film heat transfer.

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