Evaporation and condensation convection and phase change heat transfer experimental system and method

Abstract

The application discloses an experimental system for evaporation and condensation convection and phase change heat transfer, which comprises a sealed experimental cavity, an evaporation table and a condensation table arranged in the experimental cavity; the evaporation table is provided with a liquid injection joint, a liquid injection unit can inject liquid experimental working medium into the evaporation table through the liquid injection joint via a liquid pipeline, and liquid drops of the experimental working medium are formed on the upper surface of the evaporation table; the evaporation table is provided with a heating function and can heat and evaporate the liquid drops to generate steam; the evaporation table is provided with a refrigeration function and can condense the steam generated in the evaporation experiment or the steam injected into the experimental cavity from outside; at least one set of observation windows are arranged on the cavity wall of the experimental cavity, so that an observation device arranged outside the experimental cavity can observe the evaporation experiment and the condensation experiment occurring in the experimental cavity through the observation windows. The application further discloses a method for evaporation and condensation convection and phase change heat transfer experiment; the evaporation table is used for the evaporation experiment, after a group of working conditions are completed, waste gas is pumped out, pressure is controlled, a steam injection unit provides steam, and the condensation experiment is carried out on the condensation table.

Description

Technical Field

[0001] This invention relates to the field of evaporation and condensation technology, specifically to an experimental system and method for evaporation and condensation convection and phase change heat transfer. Background Technology

[0002] Evaporation and condensation are common phenomena in nature, and their phase change heat transfer (heat transfer during liquid boiling and steam condensation) process is a classic problem that physics has long studied. The evaporation and condensation cycle is greatly affected by natural (buoyancy) convection caused by gravity at every moment.

[0003] As phase change heat transfer devices continue to become more sophisticated and flexible, dimensional analysis has revealed strong similarities between condensation experiments at microscale and normal scales under microgravity. However, due to limitations of the ground-based experimental environment, it is impossible to conduct relevant experiments accurately on the ground. Therefore, it is necessary to utilize the microgravity conditions in space to conduct experimental research and compare the space experimental data with ground-based numerical simulation data to verify their accuracy.

[0004] Therefore, it is necessary to conduct scientific experiments on space evaporation and condensation phase change heat transfer using the microgravity environment in space, and to study the special phenomena of space phase change heat transfer and understand its special laws through these experiments.

[0005] Due to the unique characteristics of microgravity environments, whether simulating microgravity on the ground or sending experimental devices into space aboard spacecraft, there are certain spatial requirements for the entire experimental setup. The goal is to enable the setup to perform as many experiments as possible within a minimal space; however, existing experimental setups cannot meet this requirement. For example:

[0006] Existing Chinese patent application document 1 (publication number CN113393741A, publication date September 14, 2021) discloses an experimental apparatus for observing the phase transition process of large-sized droplets under microgravity conditions. The apparatus includes: an evaporation droplet experimental stage for forming experimental liquid into large-sized droplets and providing evaporation conditions; a liquid storage and injection unit for supplying experimental liquid to the evaporation droplet experimental stage; an optical observation unit for providing a light source to the evaporation droplet experimental stage and observing the evaporation phase transition process; an environmental monitoring unit for monitoring environmental parameters in the operating environment; and a control unit for controlling the experiment. This scheme is suitable for open evaporation stage experimental systems but cannot perform experiments under shear flow (a flow mode that generates a transverse velocity gradient field), such as in unventilated or gas-circulating conditions. It also cannot perform condensation experiments and supports relatively limited observation methods.

[0007] Existing Chinese patent application document 2 (publication number CN112378948A, publication date February 19, 2021) discloses a comprehensive measurement system and method for accurately determining the starting point of condensate film formation. The system includes a closed experimental chamber, an experimental working fluid injection unit, and an optical observation unit. The closed experimental chamber is equipped with a steam injection port, a vacuum exhaust port, and a non-condensable gas inlet. A condensation stage with controllable surface temperature is installed inside the closed experimental chamber. The experimental working fluid injection unit includes a steam generator, a steam flow controller, and a solenoid valve. The steam generator is connected to the steam injection port via the steam flow controller to inject experimental steam at a certain temperature and pressure into the closed experimental chamber. Non-condensable gas is injected into the closed experimental chamber through the non-condensable gas inlet. The optical observation unit includes a CCD camera, an infrared thermal imager, and a background light source. The background light source is installed on the inner wall of the closed experimental chamber. The CCD camera and the infrared thermal imager are installed on the displacement stage. The CCD camera records the condensate film growth process via video, and the infrared thermal imager instantly records the surface temperature of the condensation stage under the same operating conditions in real time. This method can only be used for condensation experiments, not for evaporation-related experiments. Summary of the Invention

[0008] The purpose of this invention is to provide an experimental system and method for evaporation and condensation convection and phase change heat transfer, so as to solve the technical problems existing in the prior art in which more experimental modules and experimental units can be arranged in an effective space, and evaporation and condensation experiments can be carried out simultaneously.

[0009] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0010] An experimental system for evaporation and condensation convection and phase change heat transfer includes:

[0011] The experimental chamber is a sealed cavity that provides experimental space for evaporation and condensation experiments. An evaporation platform, located inside the experimental chamber, is used for evaporation experiments. The evaporation platform has a liquid injection connector, allowing a liquid injection unit to inject liquid working fluid into the evaporation platform via a liquid pipeline through the connector, causing the working fluid to form droplets on the upper surface of the evaporation platform. The evaporation platform has a heating function, capable of heating and evaporating the droplets to generate steam. A condensation platform, also located inside the experimental chamber, is used for condensation experiments. The evaporation platform has a cooling function, capable of condensing the steam generated during the evaporation experiment or steam injected into the experimental chamber from the outside. At least one set of observation windows is provided on the walls of the experimental chamber, allowing observation equipment located outside the experimental chamber to observe the evaporation and condensation experiments occurring within the experimental chamber through these windows.

[0012] Furthermore, the experimental chamber has a steam inlet on its wall, allowing the steam injection unit to inject vaporized experimental working fluid into the chamber via a gas pipeline through the steam inlet, providing a steam-based experimental environment for the condensation experiment. The experimental chamber also has an air inlet on its wall, allowing the air injection unit to inject air into the chamber via a gas pipeline through the air inlet, thereby altering the experimental environment during evaporation and / or condensation experiments. Finally, the experimental chamber has an exhaust port on its wall, allowing the exhaust unit to extract air from inside the experimental chamber to the outside via a gas pipeline through the exhaust port, thereby adjusting the internal air pressure of the experimental chamber.

[0013] Furthermore, the top plate of the experimental chamber is provided with a top viewing window directly above the evaporation stage and the condensation stage; the experimental chamber is provided with a side viewing window on the side plate parallel to the distribution direction of the evaporation stage and the condensation stage, respectively, at a position directly opposite the evaporation stage and the condensation stage; on the inner side of the side plate on the other side parallel to the side plate, each side viewing window is provided with a set of background light sources.

[0014] Furthermore, the evaporation stage includes an evaporation base, an evaporation seat, and an evaporation base arranged sequentially from top to bottom. The evaporation seat has a droplet cavity inside, and the liquid injection connector is located on the side wall of the evaporation seat for injecting liquid experimental medium into the droplet cavity. The evaporation base has a droplet outlet hole in the vertical direction at its center, and the evaporation seat has a droplet through hole on its surface in contact with the droplet outlet hole, corresponding to the droplet outlet hole and communicating with the droplet cavity. The liquid experimental medium passes sequentially through the droplet cavity, the droplet through hole, and the droplet outlet hole, forming droplets on the evaporation seat. A heating component is provided between the evaporation seat and the evaporation base, and the evaporation seat is in contact with the heating component. Through heat conduction between the evaporation base and the evaporation seat, the droplets at the evaporation seat can be evaporated.

[0015] Furthermore, a first sensor is provided between the evaporation substrate and the evaporation base. The sensing end of the first sensor is located directly below the formed droplet, and the experimental working fluid can pass through the first sensor. The first sensor is used to measure the change in the heat flow of the droplet. At least two second sensors are provided on the evaporation base near the evaporation substrate, such that the sensing ends of the second sensors are located directly below the formed droplet and are not located inside the droplet cavity. The second sensors are used to measure the temperature at different locations of the droplet. A third sensor is also provided on the evaporation base. The third sensor is used to feed back the collected temperature of the evaporation base to the evaporation temperature control module, which adjusts the temperature of the heating component. A fourth sensor is also provided on the evaporation substrate. The fourth sensor is used to measure the temperature of the air near the droplet.

[0016] Furthermore, the evaporation substrate has a disc-shaped structure, and the surface of the evaporation substrate that carries the droplets is provided with at least one annular groove around the periphery of the droplet outlet. The evaporation substrate has a vertically upward protruding edge at the edge position to prevent the experimental working medium from overflowing from the evaporation substrate.

[0017] Furthermore, the condensation stage includes a heat-conducting element and a heat-insulating layer wrapped around the heat-conducting element. The top of the heat-conducting element is exposed in the experimental chamber, and a refrigeration component is provided at the bottom of the heat-conducting element. The heat-conducting element is in contact with the refrigeration component, so that the temperature of the top of the heat-conducting element can be lower than the temperature inside the experimental chamber, thereby allowing the vapor above the heat-conducting element to condense on the top of the heat-conducting element.

[0018] Furthermore, a fifth sensor is provided inside the heat conduction component near the top. The fifth sensor is used to measure the change in heat flow of droplets falling onto the top of the heat conduction component during the condensation process of the steam in the experimental chamber. A sixth sensor and a seventh sensor are also provided inside the heat conduction component. The sixth sensor is used to monitor the temperature of the heat conduction component, and the seventh sensor is used to feed back the temperature of the heat conduction component to the condensation temperature control module of the refrigeration component, which then adjusts the temperature of the refrigeration component.

[0019] To address the aforementioned technical problems, the present invention further provides the following technical solution:

[0020] An experimental method for evaporation and condensation convection and phase change heat transfer experiments, wherein the evaporation and condensation convection and phase change heat transfer experimental system is used to conduct evaporation and condensation experiments;

[0021] The steps of the evaporation experiment include:

[0022] Step 011: Create a sealed experimental chamber environment for the evaporation experiment;

[0023] Step 012: The liquid injection unit injects the experimental working medium into the evaporation platform, so that the experimental working medium overflows from the droplet outlet of the evaporation base and forms droplets that meet the experimental requirements in the evaporation base.

[0024] Step 013: The evaporation temperature control module raises the temperature of the heating component and heats the droplets formed on the evaporation base through heat conduction between the evaporation base and the evaporation substrate until they evaporate to form steam.

[0025] Step 014: During the droplet evaporation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal.

[0026] Step 015: During the droplet evaporation process, adjust the experimental environment inside the experimental chamber to observe the changes in the droplet evaporation rate, temperature, and heat flow.

[0027] The steps of the condensation experiment include:

[0028] Step 021: Create a sealed experimental chamber environment for the condensation experiment, so that the experimental chamber is filled with steam;

[0029] Step 022: The condensation temperature control module lowers the temperature of the heat transfer component, allowing the steam above the heat transfer component to condense at the top of the component and form droplets.

[0030] Step 023: During the steam condensation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal.

[0031] Step 024: During the steam condensation process, steam is injected into the experimental chamber through the steam injection unit to meet the requirements of the condensation experiment for the steam environment.

[0032] Step 025: During the steam condensation process, adjust the experimental environment inside the experimental chamber to observe the changes in the droplet evaporation rate, temperature, and heat flow.

[0033] Furthermore, in the evaporation experiment,

[0034] After multiple evaporation experiments, a saturated vapor pressure is generated inside the experimental chamber. The saturated vapor inside the experimental chamber is extracted by the pumping unit, while fresh air is injected into the experimental chamber by the air injection unit to regulate the pressure inside the experimental chamber.

[0035] In the condensation experiment,

[0036] In step 021, the condensation experiment is carried out using the steam environment generated by the evaporation experiment; or, in an environment where there is no steam in the sealed cavity, steam is injected into the experimental cavity through the steam injection unit to meet the requirements of the condensation experiment for the steam environment.

[0037] In step 025, during the steam condensation process, fresh air is injected through an air injection unit to test the effect of non-condensable gas on the steam condensation process.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] This invention provides an experimental system and method for evaporation, condensation, convection, and phase change heat transfer, which can be applied to various environments such as microgravity or the ground. The experimental chamber integrates an evaporation stage and a condensation stage, which can be used to conduct both evaporation and condensation experiments.

[0040] The experimental chamber is uniformly connected to the liquid injection device, control device, power supply, etc. The monitoring device can observe the morphological changes and temperature distribution of the droplet / liquid layer evaporation process and the vapor condensation process according to the actual situation. It supports a variety of observation methods, including but not limited to laser interferometry morphological observation, infrared observation and high-definition camera observation. In space, it does not require astronaut operation and can be controlled by ground personnel, which reduces the difficulty of conducting experiments in space and saves labor costs. Attached Figure Description

[0041] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0042] Figure 1 This is an external schematic diagram of the experimental system for evaporation, condensation, convection, and phase change heat transfer of the present invention.

[0043] Figure 2 This is a schematic diagram of the internal structure of the experimental chamber;

[0044] Figure 3 This is a schematic diagram of the evaporation platform.

[0045] Figure 4 This is an exploded view of the evaporation platform;

[0046] Figure 5 This is a cross-sectional view of the evaporation platform;

[0047] Figure 6 This is a diagram showing the sensor distribution inside the evaporation base.

[0048] Figure 7 This is a schematic diagram of the condenser platform.

[0049] Figure 8 This is a cross-sectional view of the assembly between the condensation stage and the experimental chamber.

[0050] The labels in the diagram represent the following:

[0051] 1-Experimental chamber, 11-Steam inlet, 12-Air inlet, 13-Evacuation port, 14-Liquid injection hole, 15-Through hole, 16-Connector;

[0052] 2-Evaporation stage, 21-Liquid injection connector, 22-Evaporation substrate, 23-Evaporation base, 24-Evaporation base, 25-Droplet cavity, 26-Droplet outlet, 27-Droplet through hole, 28-Heating component, 291-First sensor, 292-Second sensor, 293-Third sensor, 294 Sensor bracket;

[0053] 231 - First temperature measuring hole, 232 - Second temperature measuring hole;

[0054] 221-Annular groove, 222-Raised edge, 223-Mounting part;

[0055] 3-Condensing platform, 31-Heat conduction component, 32-Insulation layer, 33-Refrigeration component, 341-Fifth sensor, 342-Sixth sensor, 343-Seventh sensor, 344-Differential thermocouple, 35-Third temperature measuring port;

[0056] 41-Top window, 42-Side window, 43-Background light source. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] like Figure 1 and Figure 2 As shown, the present invention provides a specific implementation of an experimental system for evaporation and condensation convection and phase change heat transfer, including an evaporation stage 2 and a condensation stage 3 disposed in an experimental chamber 1.

[0059] Experimental chamber 1 is a sealed chamber that provides experimental space for evaporation and condensation experiments.

[0060] The experimental chamber 1 can be made of metal, including but not limited to aluminum-magnesium alloy or aluminum alloy. Aluminum-magnesium alloy has the advantages of being lightweight, having high tensile strength, good load-bearing capacity, and high dimensional stability. Aluminum alloy has the advantages of being lightweight, having high strength, good corrosion resistance, good processing performance, and being easy to recycle. The materials that can be selected for the experimental chamber 1 include but are not limited to these, and are not restricted here.

[0061] In this embodiment, the experimental chamber 1 is preferably an approximately cuboid structure, using a combination of a panel and reinforcing ribs. This configuration increases the structural strength of the experimental chamber 1, enabling it to withstand negative pressure experimental environments.

[0062] Furthermore, in order to minimize the space occupied by the entire experimental cavity 1 while ensuring the experimental effect, the inventors, after multiple experiments and demonstrations, finally determined that the envelope size of the entire experimental cavity 1 should not exceed 240mm×140mm×100mm, and the inner cavity size should not be less than 180mm×100mm×75mm. This setting ensures that the experimental cavity 1 has sufficient inner cavity space while allowing the entire experimental cavity 1 to occupy a smaller space, thereby improving the space utilization rate of the experimental cavity 1.

[0063] It should be noted that the envelope size refers to the maximum external dimensions of an item, which is the size of the box required to place the item in the smallest possible box.

[0064] Furthermore, the wall thickness of the panels on the four sides of the experimental cavity 1 is preferably 10 mm, the wall thickness of the panels on the top and bottom sides of the experimental cavity 1 is preferably 4 mm, and the thickness of the reinforcing ribs is preferably 6 mm. The above-mentioned size selection is the optimal solution under the premise that the envelope size of the experimental cavity 1 is determined, while keeping the inner cavity size as large as possible and ensuring the structural strength of the entire experimental cavity 1. In other embodiments, the thickness of the panels and reinforcing ribs can be adaptively adjusted according to the actual situation, and is not limited here.

[0065] Evaporation platform 2 is set inside experimental chamber 1 for evaporation experiments. Evaporation platform 2 has a liquid injection connector 21. The liquid injection unit can inject liquid experimental working medium into evaporation platform 2 through liquid pipeline via liquid injection connector 21, so that the experimental working medium forms droplets on the upper surface of evaporation platform 2. Evaporation platform 2 has a heating function, which can heat and evaporate the droplets to generate steam.

[0066] The condensing platform 3 is located inside the experimental chamber 1 and is used for condensation experiments; the evaporating platform 2 has a refrigeration function and can condense the steam generated by the evaporation experiment or the steam injected into the experimental chamber 1 from the outside.

[0067] Evaporation stage 2 can be used to study the evaporation process of droplets with a diameter range of 5mm-10mm and the evaporation process of liquid layers with a thickness of no more than 2mm; condensation stage 3 can be used to study the condensation process of vapor condensing into liquid.

[0068] It should be noted that: 1. The diameter of the droplets and the thickness of the liquid layer studied in the evaporation stage 2 can be set according to the requirements of subsequent scientific experiments on space evaporation and condensation phase change heat transfer. Therefore, they can be adjusted adaptively according to the actual situation. This does not constitute a limitation on the size of the droplets.

[0069] 2. During the experiment, if the diameter of the droplet and the thickness of the liquid layer are too small, the evaporation rate of the droplet will be too fast, and the morphological changes of the droplet and liquid layer cannot be observed in time, so experimental images and data cannot be obtained. If the diameter of the droplet and the thickness of the liquid layer are too large, the evaporation rate of the droplet will be too slow, and the surface tension distribution on the gas-liquid interface will be uneven when there is a temperature gradient at the gas-liquid interface. This will cause the surface tension driven flow phenomenon of the liquid around the interface to be insignificant, and the morphological changes of the droplet and liquid layer cannot be observed, while also wasting reaction time.

[0070] The steam condensed by the condensing platform 3 can be the steam generated during the evaporation experiment on the evaporation platform 2, or the steam supplied to the experimental chamber 1 by the external device. The source of the steam condensed by the condensing platform 3 is not limited here.

[0071] Meanwhile, in order to make the layout of the entire experimental chamber 1 more compact and make reasonable use of the internal space of the experimental chamber 1, in this embodiment, the evaporation stage 2 and the condensation stage 3 are symmetrically distributed along the length of the experimental chamber 1; in order to meet the observation requirements, the condensation stage 3 and the evaporation stage 2 need to be located at the same height.

[0072] The experimental chamber 1 has at least one set of observation windows on its walls, so that observation equipment located outside the experimental chamber 1 can observe the evaporation and condensation experiments that occur inside the experimental chamber 1 through the observation windows.

[0073] This embodiment provides a specific example of the observation window, as shown in the figure:

[0074] The top plate of the experimental chamber 1 is provided with a top viewing window 41 directly above the evaporation platform 2 and the condensation platform 3. The glass embedded in the top viewing window 41 needs to ensure the airtightness between it and the top plate.

[0075] Furthermore, the glass embedded in the top viewing window 41 can be observation glass that can transmit both infrared and visible light. The observation equipment located outside the experimental cavity 1 is not shown in the figure and is located directly above the experimental cavity 1. The observation equipment is preferably an infrared thermal imager and a high-definition camera CCD, but it is not limited to these, and is not limited here.

[0076] This embodiment uses an infrared thermal imager and a high-definition CCD camera as examples to illustrate the morphological changes during the droplet evaporation and vapor condensation processes.

[0077] Furthermore, since the results observed by the infrared thermal imager and the high-definition camera have different focuses, in order to fully obtain different experimental information during the same evaporation and condensation experiment, both the infrared thermal imager and the high-definition camera are connected to a displacement mechanism (not shown in the figure). The displacement mechanism can realize the mutual conversion between the two devices, the infrared thermal imager and the high-definition camera, at a single observation position of evaporation stage 2 or condensation stage 3, and the movement between the two observation positions of evaporation stage 2 and condensation stage 3. During observation, the center of the lens of the infrared thermal imager and the high-definition camera must be coaxial with the center of the liquid droplet in the evaporation experiment, and a certain distance must be maintained between the lens of the infrared thermal imager and the high-definition camera and evaporation stage 2 and condensation stage 3.

[0078] During the experiment, image data, temperature, and heat flow data captured by an infrared thermal imager and a high-definition camera were collected through an external data acquisition system and transmitted to a data terminal for subsequent analysis and processing by the staff at the data terminal.

[0079] On the long side plate of the experimental chamber 1, which is parallel to the distribution direction of the evaporation platform 2 and the condensation platform 3, there are side viewing windows 42 respectively at the positions directly opposite the evaporation platform 2 and the condensation platform 3. The glass embedded in the side viewing windows 42 needs to ensure the airtightness between it and the top plate.

[0080] Furthermore, the glass embedded in the long side plate can be optical-grade glass such as germanium chemical Ge glass or zinc sulfide chemical ZnS glass. These optical-grade glasses have advantages such as good refractive index uniformity and consistency, high transmittance in the mid-infrared band, high hardness, and strong resistance to harsh environments.

[0081] The external observation equipment, not shown in the diagram, can be set near the side window 42. The observation equipment is preferably an infrared thermal imager and a high-definition CCD camera, but is not limited to these.

[0082] This embodiment uses an infrared thermal imager and a high-definition CCD camera as examples to illustrate the morphological changes during the droplet evaporation and vapor condensation processes.

[0083] The side window 42 can function the same as the top window 41. The way the side window 42 works with the infrared thermal imager and the high-definition camera can also be the same as the way the top window 41 works with the infrared thermal imager and the high-definition camera. The processing method of the relevant data collected by the infrared thermal imager and the high-definition camera is also the same, which will not be elaborated here.

[0084] Furthermore, in order to improve the quality of observation, each side window 42 is provided with a set of background light sources 43 on the inner side of the side plate on the opposite side parallel to the side plate, so as to provide light source during the shooting process of the high-definition camera CCD.

[0085] In this embodiment, to ensure the smooth progress of the experiment and to achieve experimental diversity, the following structure is also included:

[0086] The experimental chamber 1 is provided with a steam inlet 11 on its wall. The steam inlet 11 can be located on the top plate or the side plate of the experimental chamber 1, preferably on the side plate. The steam injection unit can inject the steam experimental working medium into the experimental chamber 1 through the steam inlet 11 via a gas pipeline, providing a steam experimental environment for the condensation experiment.

[0087] An air inlet 12 is provided on the wall of the experimental chamber 1. The air inlet 12 can be located on the top plate or the side plate of the experimental chamber 1, preferably on the side plate. The air injection unit can inject air into the experimental chamber 1 through the air inlet 12 via a gas pipeline to change the experimental environment during evaporation and / or condensation experiments.

[0088] The experimental chamber 1 is provided with an air extraction port 13 on its cavity wall. The air extraction port 13 can be located on the top plate or the side plate of the experimental chamber 1, preferably on the side plate. The air extraction unit can extract the air inside the experimental chamber 1 to the outside of the experimental chamber 1 through the air extraction port 13 via the gas pipeline, so as to adjust the air pressure inside the experimental chamber 1.

[0089] The steam injection unit, air injection unit, and air extraction unit located outside the experimental chamber 1 work together to regulate parameters such as the internal environment, gas type, and gas pressure of the experimental chamber 1.

[0090] Furthermore, the experimental chamber 1 is provided with a liquid injection hole 14 on its wall. The liquid injection hole 14 can be located on the top plate of the experimental chamber 1 or on the side plate of the experimental chamber 1, preferably on the side plate near the evaporation stage 2. The liquid pipeline required for liquid injection passes through the liquid injection hole 14, and the sealing between the liquid pipeline and the liquid injection hole 14 must be ensured.

[0091] Furthermore, the liquid pipelines are designed not to obstruct the view of the top viewing window 41 and the side viewing window 42; the arrangement of the liquid pipelines in the experimental chamber 1 and the materials selected for the liquid pipelines can be adapted to the actual situation, and no restrictions are imposed here.

[0092] This embodiment also provides an example of an evaporation platform 2, such as... Figures 3-6 As shown:

[0093] The evaporation platform 2 includes an evaporation base 22, an evaporation base 23, and an evaporation base 24 arranged sequentially from top to bottom. Consideration of space utilization makes the structure of the entire evaporation platform 2 more compact, and the three are set at the same geometric center.

[0094] The evaporation base 23 has a droplet cavity 25 inside, and the liquid injection connector 21 is located on the side wall of the evaporation base 23. The external liquid injection unit is connected to the liquid injection connector 21 through a liquid pipeline, which can inject liquid experimental working fluid into the droplet cavity 25.

[0095] The evaporation base 22 has a droplet outlet hole 26 that penetrates the evaporation base 22 in the vertical direction at the center position. The evaporation base 23 has a droplet through hole 27 that is connected to the droplet cavity 25 on the surface that contacts the evaporation base 23, corresponding to the droplet outlet hole 26. The liquid experimental working medium passes through the droplet cavity 25, the droplet through hole 27 and the droplet outlet hole 26 in sequence to form droplets on the evaporation base 23.

[0096] A heating component 28 is provided between the evaporation base 23 and the evaporation base 24, and the evaporation base 23 is in contact with the heating component 28. Through heat conduction between the evaporation base 22 and the evaporation base 23, the droplets at the evaporation base 22 can be evaporated.

[0097] Meanwhile, in order to create different experimental environments during the evaporation process, the heat received by the droplets needs to be at a fixed temperature or vary within a certain temperature range during the evaporation process; therefore, the heating component 28 is connected to the evaporation temperature control module located outside the experimental chamber 1. The evaporation temperature control module controls the temperature change of the heating component 28 so that the heat received by the droplets can be at a fixed temperature or vary within a certain temperature range.

[0098] The heating component 28 preferably uses a thin-film heating element, specifically a thin-film heating element produced by Beijing Hongyu Aerospace Technology Co., Ltd., which has a military-grade product history and exhibits excellent stability even under special pressure environments.

[0099] Regarding the material selection for the evaporation substrate 22, the evaporation base 23, and the evaporation base 24, the following embodiments are provided:

[0100] Considering the wettability of the liquid and the influence of metal emissivity on infrared radiation, the substrate is made of blackened aluminum.

[0101] The evaporation base 23 needs to conduct the heat from the heating component 28 to the evaporation base 23. Therefore, a metal material is selected. The metal material has a certain strength and thermal conductivity. The metals that can be selected include, but are not limited to, copper or aluminum.

[0102] The evaporation base 24 mainly serves as a heat insulation layer to prevent the heat from the thin film heating element from being conducted downwards, thus avoiding heat loss and providing a heat preservation effect. Therefore, materials with good heat insulation performance should be selected. ABS acrylonitrile-butadiene-styrene plastic can be selected, but it is not limited to this. ABS plastic has the characteristics of high gloss, wear resistance, impact resistance, and being almost unaffected by temperature and humidity.

[0103] To further facilitate the monitoring of heat generated during the evaporation experiment, multiple sensors are installed on evaporation platform 2, as follows:

[0104] A first sensor 291 is provided between the evaporation substrate 22 and the evaporation base 23. The sensing end of the first sensor 291 is located directly below the formed droplet. The experimental working medium can pass through the first sensor 291. The first sensor 291 is used to measure the change in heat flow during the process of droplet evaporation to generate steam, and transmits the collected data to the data terminal for subsequent analysis and processing by the data terminal staff.

[0105] The first sensor 291 is preferably a high-precision ultra-thin heat flow sensor with a measurement input range of ±200kW / m2, an operating temperature range of -180℃~200℃, an accuracy better than 3% of the indicated value, a nominal sensitivity better than 0.3μV / (W / m2), and a response time of 300 milliseconds.

[0106] In addition, its thickness is only 400μm, which makes it easy to fix between the evaporation substrate 22 and the evaporation base 23. In order not to affect the heat conduction efficiency between the evaporation substrate 22 and the evaporation base 23, the side of the evaporation substrate 22 or the evaporation base 23 that contacts the first sensor 291 has a groove. The first sensor 291 can be stuck in the groove, so that the evaporation substrate 22 and the evaporation base 23 can be fitted together.

[0107] Furthermore, a sensor bracket 294 is provided on the evaporation base 23 corresponding to the first sensor 291, for supporting and fixing the first sensor 291.

[0108] The evaporation base 23 is provided with at least two second sensors 292 near the evaporation substrate 22, such that the sensing end of the second sensor 292 is located directly below the formed droplet, and the sensing end of the second sensor 292 is not located inside the droplet cavity 25. The second sensor 292 is used to measure the temperature at different positions of the droplet and transmit the collected data to the data terminal for subsequent analysis and processing by the data terminal staff.

[0109] In this embodiment, three second sensors 292 are provided. The side wall of the evaporation base 23 has three first temperature measuring holes 231 along the horizontal plane, and the second sensors 292 are installed in the first temperature measuring holes 231.

[0110] The second sensor 292 is a temperature sensor or a thermocouple, preferably a thermocouple, with the sensing end of the thermocouple located inside the evaporation substrate 22.

[0111] The data collected by the first sensor 291 and the second sensor 292 help to reflect the effects of evaporation and thermocapillary convection on the heat transfer characteristics inside the droplet.

[0112] The evaporation base 23 is also equipped with a third sensor 293, which is used to feed back the collected temperature of the evaporation base 23 to the evaporation temperature control module, and adjust the temperature of the heating component 28 through the evaporation temperature control module.

[0113] A second temperature measuring hole 232 is opened on the side wall of the evaporation base 23, and a third sensor 293 is installed in the second temperature measuring hole 232.

[0114] The third sensor 293 is a temperature sensor or a thermocouple, preferably a thermocouple, with the sensing end of the thermocouple located inside the evaporation substrate 22.

[0115] A fourth sensor is also installed at the evaporation substrate 22. The fourth sensor is used to measure the temperature of the air near the droplet and transmit the collected data to the data terminal for subsequent analysis and processing by the data terminal staff.

[0116] The fourth sensor is a temperature sensor or a thermocouple, preferably a thermocouple. The sensing end of the thermocouple is located near the droplet. Specifically, the fourth sensor can be set on the evaporation base 23 or on the inner wall of the experimental chamber 1. The specific location is not limited.

[0117] In this embodiment, the following example is provided to prevent the experimental working fluid from overflowing from the evaporation stage 2.

[0118] like Figure 4 As shown: the evaporation substrate 22 has a disc-shaped structure. The surface of the evaporation substrate 22 that carries the droplets has at least one annular groove 221 around the periphery of the droplet outlet 26. The evaporation substrate 22 has a vertically upward protruding edge 222 at the edge position to prevent the experimental working medium from overflowing from the evaporation substrate 22.

[0119] Specifically, the experimental working medium overflows from the droplet outlet 26 at the top of the evaporation substrate 22 to form droplets. If the amount overflowing from the droplet outlet 26 is too large, the edge of the droplet will spread to the surrounding area until the outer edge of the droplet spreads to the annular groove 221. The surface tension of the droplet combined with the annular groove 221 restricts the edge of the droplet, preventing the edge of the droplet from spreading further to the surrounding area, so that the experiment can proceed smoothly.

[0120] Based on the above, if the experimental working medium continues to overflow through the droplet outlet 26, the edge of the droplet will further diffuse to the surrounding area. The protruding edge 222 at the edge of the evaporation substrate 22 can block the edge of the droplet to prevent the experimental working medium from overflowing the evaporation substrate 22.

[0121] An installation part 223 is pre-formed on the outer edge of the evaporation base 22, with bolt holes reserved for assembly and fixation with the evaporation base.

[0122] Furthermore, in this embodiment, the dimensions of the evaporation substrate 22 are limited based on the overall dimensions of the experimental chamber 1, as follows:

[0123] The diameter of the evaporation substrate 22 can be in the range of 10mm-20mm. This setting ensures that the evaporation substrate 22 has enough space to form droplets, and at the same time, it is conducive to the compact design of the evaporation stage 2. In this embodiment, the diameter of the evaporation substrate 22 is preferably 20mm.

[0124] The diameter of the annular groove 221 is half the diameter of the evaporation substrate 22. In this embodiment, the diameter of the annular groove 221 is 10 mm.

[0125] If the diameter of the droplet outlet 26 is too small, it is easily blocked by the experimental working medium, preventing the formation of droplets for the experiment and thus hindering the evaporation experiment. If the diameter of the droplet outlet 26 is too large, the liquid flow rate will be too fast, preventing the formation of droplets of precise size. It will also affect the contact area between the droplets and the evaporation substrate 22, causing interference in the evaporation experiment and affecting the accuracy of the experimental results. Therefore, the diameter of the droplet outlet 26 is 0.5-1 mm. In this embodiment, the diameter of the droplet outlet 26 is preferably 0.7 mm.

[0126] This results in droplets with a diameter of 5-10 mm and a liquid layer height of 2 mm formed at the droplet outlet 26 of the evaporation substrate 22.

[0127] This embodiment also provides an example of the condensation stage 3, such as... Figure 7 and Figure 8 As shown:

[0128] The condensation platform 3 includes a heat conduction element 31 and a heat insulation layer 32 wrapped around the heat conduction element 31. The top of the heat conduction element is exposed in the experimental chamber 1, and a cooling component 33 is provided at the bottom of the heat conduction element 31. The heat conduction element 31 is in contact with the cooling component 33, so that the temperature of the top of the heat conduction element 31 can be lower than the temperature inside the experimental chamber 1, thereby allowing the vapor above the heat conduction element 31 to condense on the top of the heat conduction element 31.

[0129] The heat conduction element 31 has a cylindrical structure. The heat conduction element 31 conducts the heat generated by the cooling component 33 to the top of the heat conduction element 31. Therefore, a metal material is selected. The metal material has a certain strength and thermal conductivity. The metals that can be selected include, but are not limited to, copper or aluminum.

[0130] The insulation layer 32 is made of polytetrafluoroethylene (PTFE) or Teflon, which is a polymer compound formed by the polymerization of tetrafluoroethylene. It has excellent chemical stability, corrosion resistance, sealing performance, high lubricity and non-stickiness, electrical insulation and good anti-aging resistance. The materials that can be selected for the insulation layer 32 include, but are not limited to, these. They can be adjusted according to the actual situation and are not limited here.

[0131] The cooling component 33 uses a semiconductor cooler TEC. The semiconductor cooler TEC has a layered structure, which occupies a small space and is suitable for this experimental device. Due to the characteristics of the semiconductor cooler TEC, one side is the "hot" side and the other side is the "cold" side. The "cold" side of the semiconductor cooler TEC is attached to the bottom of the heat conduction component 31.

[0132] Furthermore, in this embodiment, to avoid the "hot" side of the thermoelectric cooler TEC potentially affecting the temperature inside the experimental chamber 1, as well as the heat conduction of the heat conduction element 31 itself, the thermoelectric cooler TEC is configured as follows:

[0133] At the bottom of the experimental chamber 1, where the condenser platform 3 is located, there is a through hole 15. The through hole 15 is a cylindrical countersunk hole. The bottom of the heat conduction component 31 extends downward to form a boss structure. The heat insulation layer 32 is also set as a boss structure. The entire condenser platform 3 enters the experimental chamber 1 from the outside through the through hole 15. A sealing ring is provided between the through hole 15 and the heat insulation layer 32 of the condenser platform 3. The bottom of the heat conduction component is in contact with the "cold" side of the thermoelectric cooler TEC. The thermoelectric cooler TEC is fixed to the outside of the experimental chamber 1. With this arrangement, the heat from the "hot" side of the thermoelectric cooler TEC will not affect the environment inside the experimental chamber 1. Moreover, the experimental chamber 1 and the heat conduction component 31 are completely isolated by the heat insulation layer 32 to ensure the stability and accuracy of the entire experiment.

[0134] To further facilitate the monitoring of heat generated during the condensation experiment, multiple sensors are installed on condensation stage 3, as follows:

[0135] A fifth sensor 341 is provided inside the heat conduction component 31 near the top. The fifth sensor 341 is used to measure the change in heat flow rate of the droplets that fall to the top of the heat conduction component 31 during the process of steam condensing into droplets in the experimental chamber 1.

[0136] The fifth sensor 341 is preferably a high-precision ultra-thin heat flow sensor with a measurement input range of ±200kW / m2, an operating temperature range of -180℃ to 200℃, an accuracy better than 3% of the indicated value, a nominal sensitivity better than 0.3μV / (W / m2), and a response time of 300 milliseconds. In addition, its thickness is only 400μm. Specifically, a slot is cut along the horizontal plane above the heat conduction element 31 near the top, into which the heat flow sensor can be inserted.

[0137] The heat conduction component 31 is equipped with a sixth sensor 342 and a seventh sensor 343. The sixth sensor 342 is used to monitor the temperature of the heat conduction component 31, and the seventh sensor 343 is used to feed back the temperature of the heat conduction component 31 to the condensation temperature control module of the cooling component 33. The condensation temperature control module then adjusts the temperature of the cooling component 33. The condensation temperature control module is not shown in the figure and is located outside the experimental chamber 1.

[0138] The sixth sensor 342 and the seventh sensor 343 are temperature sensors or thermocouples, preferably thermocouples, with the sensing end of the thermocouple located inside the heat conduction element 31.

[0139] Furthermore, two sets of thermocouples are respectively installed inside the heat conduction component 31 at different heights to form differential thermocouples 344, which can measure the temperature difference at different positions of the heat conduction component 31 and be used to invert the change of heat transfer coefficient during the condensation experiment.

[0140] The sidewall of the heat conduction component 31 has four third temperature measuring holes 35 that penetrate the heat insulation layer 32 at equal intervals from top to bottom, parallel to the horizontal plane. From top to bottom, the first third temperature measuring hole 35 is used to install the seventh sensor 343, the third third temperature measuring hole 35 is used to install the sixth sensor 342, and the remaining two third temperature measuring holes 35 are used to install the differential thermocouple 344.

[0141] The experimental chamber 1 is also equipped with a pressure sensor (not shown in the figure). The pressure sensor is used to monitor the environmental pressure inside the experimental chamber 1 as well as the environmental pressure during evaporation and condensation experiments. As long as this function can be achieved, the installation position of the pressure sensor can be adjusted according to the actual situation. There is no limitation here.

[0142] Specifically, the pressure sensor selected is the CTE8000 series product from SensorTechnics, Germany, with a pressure range of 0-2 bar, an output signal of 0-5 VDC, and an accuracy of ±0.1% FSO.

[0143] In this embodiment, the experimental chamber is assembled and fixed by bolts, and the sealing between the components is achieved by sealing gaskets; each component needs to have bolt holes reserved for assembly (not shown in the figure).

[0144] In this embodiment, multiple sensors and heating components 28 at the evaporation stage 2 and multiple sensors and cooling components 33 at the condensation stage 3 all need to be connected to a power supply module located outside the experimental chamber 1. The data collected by the sensors needs to be fed back to the corresponding data terminal. The evaporation temperature control module and the condensation temperature control module adjust the temperature of the heating components 28 and the cooling components 33, respectively. The relevant power supply lines, data transmission lines and control lines are all integrated on a connector 16. The end of the connector 16 located outside the experimental chamber 1 is provided with multiple sockets. The external module is connected to the corresponding sockets through a plug to ensure the connectivity of the power supply lines, data transmission lines and control lines of the entire experimental device.

[0145] The ground and space evaporation and condensation device provided in this embodiment can perform experiments including but not limited to: droplet evaporation experiments and steam condensation experiments under microgravity conditions and various operating conditions. At the same time, the ground and space evaporation and condensation device provided in this embodiment can also be applied to the ground environment, which can be understood as the Earth environment. The difference between space and the ground is the difference in the gravitational field, which makes the morphology of the droplets different during the experiment. Experiments conducted in space can obtain a more ideal physical model.

[0146] Specifically, the present invention also provides a specific implementation method for an experimental method of evaporation and condensation convection and phase change heat transfer experiment, which uses an evaporation and condensation convection and phase change heat transfer experimental system to conduct evaporation and condensation experiments.

[0147] Specifically, evaporation or condensation experiments can be conducted separately multiple times, or steam and condensation experiments can be conducted sequentially.

[0148] The steps of the evaporation experiment include:

[0149] Step 011: Create a sealed experimental chamber 1 environment for the evaporation experiment.

[0150] Step 012: The liquid injection unit injects the experimental working medium into the evaporation platform 2, so that the experimental working medium overflows from the droplet outlet 26 of the evaporation base 22 and forms droplets that meet the experimental requirements in the evaporation base 23.

[0151] Step 013: The evaporation temperature control module raises the temperature of the heating component 28, and heats the droplets formed on the evaporation base 22 through heat conduction between the evaporation base 23 and the evaporation substrate 22 until they evaporate to form steam.

[0152] Step 014: During the droplet evaporation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal.

[0153] Step 015: During the droplet evaporation process, adjust the experimental environment inside experimental chamber 1 to observe the changes in the droplet evaporation rate, temperature, and heat flow.

[0154] After multiple evaporation experiments, saturated vapor pressure is generated in experimental chamber 1. The saturated vapor in experimental chamber 1 is extracted by the air extraction unit, while fresh air is injected into experimental chamber 1 by the air injection unit to regulate the pressure inside experimental chamber 1.

[0155] The steps of the condensation experiment include:

[0156] Step 021: Create a sealed experimental chamber 1 environment for the condensation experiment, so that the experimental chamber 1 is filled with steam.

[0157] Furthermore, after conducting multiple evaporation experiments, the existing vapor in the experimental chamber can be used for condensation experiments to save on the loss of the experimental liquid working fluid.

[0158] Alternatively, steam can be injected into experimental chamber 1 through a steam injection unit in a steam-free environment within the sealed chamber to meet the steam environment requirements of the condensation experiment.

[0159] Furthermore, after completing a set of condensation experiments, the steam generator provides steam again by extracting waste gas and controlling the pressure, and the next set of condensation experiments is carried out on the condensation platform.

[0160] Step 022: The condensation temperature control module lowers the temperature of the heat transfer element 31, so that the steam above the heat transfer element 31 can condense on the top of the heat transfer element 31 and form droplets.

[0161] Step 023: During the steam condensation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal.

[0162] Step 024: During the steam condensation process, steam is injected into the experimental chamber 1 through the steam injection unit to meet the requirements of the steam environment for the condensation experiment.

[0163] Step 025: During the steam condensation process, adjust the experimental environment inside experimental chamber 1 to observe the changes in the droplet evaporation rate, temperature, and heat flow.

[0164] During the steam condensation process, fresh air is injected through an air injection unit to experimentally study the effect of non-condensable gases on the steam condensation process.

[0165] This invention provides an experimental system and method for evaporation, condensation, convection, and phase change heat transfer, which can be applied to various environments such as microgravity or the ground. The experimental chamber integrates an evaporation stage and a condensation stage, which can perform both evaporation and condensation experiments, as well as various experiments such as droplet evaporation, liquid layer evaporation, and condensation.

[0166] Meanwhile, because the experimental chamber is equipped with a left and a right opening, and the left and right openings work together, it is possible to complete the working conditions under shear flow (including but not limited to no ventilation conditions or gas circulation conditions).

[0167] By integrating the evaporation stage and condensation stage inside the experimental chamber, and connecting the liquid injection device, control device, power supply, etc. to the outside of the experimental chamber, the monitoring device can observe the morphological changes and temperature distribution of the droplet / liquid layer evaporation process and the vapor condensation process according to the actual situation. The observation methods are diverse, including but not limited to laser interferometry morphological observation, infrared observation and high-definition camera observation. In space, no astronaut operation is required, and it can be controlled by ground personnel, which reduces the difficulty of conducting experiments in space and saves labor costs.

[0168] After the experiment, various evaporation and condensation heat transfer experimental data and images can be obtained, which can provide a basis for many aspects such as the basic laws of heat and mass transfer at the gas-liquid interface, theoretical research on the stability of the evaporation interface, and the development of space phase change heat transfer equipment.

[0169] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. An experimental system for evaporation and condensation convection and phase change heat transfer, characterized in that, include: Experimental chamber (1) is a sealed chamber that provides experimental space for evaporation and condensation experiments; An evaporation platform (2) is set inside the experimental chamber (1) for conducting evaporation experiments. The evaporation platform (2) has a liquid injection connector (21). The liquid injection unit can inject liquid experimental working fluid into the evaporation platform (2) through the liquid injection connector (21) via a liquid pipeline, and the experimental working fluid forms droplets on the upper surface of the evaporation platform (2). The evaporation platform (2) has a heating function, which can heat and evaporate the droplets to generate steam. A condensing platform (3) is set inside the experimental chamber (1) for conducting condensation experiments. The condensing platform (3) has a refrigeration function and can condense the steam generated by the evaporation experiment or the steam injected into the experimental chamber (1) from the outside. The experimental chamber (1) is provided with at least one set of observation windows, so that the observation equipment located outside the experimental chamber (1) can observe the evaporation and condensation experiments that occur in the experimental chamber (1) through the observation windows.

2. The experimental system for evaporation, condensation, convection, and phase change heat transfer according to claim 1, characterized in that, The experimental chamber (1) is provided with a steam inlet (11) on its wall. The steam injection unit can inject the steam experimental working medium into the experimental chamber (1) through the steam inlet (11) via a gas pipeline, so as to provide a steam experimental environment for the condensation experiment. The experimental chamber (1) is provided with an air inlet (12) on its cavity wall. The air injection unit can inject air into the experimental chamber (1) through the air inlet (12) via a gas pipeline to change the experimental environment during the evaporation experiment and / or condensation experiment. The experimental chamber (1) has an air extraction port (13) on its wall. The air extraction unit can extract the air inside the experimental chamber (1) to the outside of the experimental chamber (1) through the air extraction port (13) via the gas pipeline, so as to adjust the air pressure inside the experimental chamber (1).

3. The experimental system for evaporation, condensation, convection, and phase change heat transfer according to claim 1, characterized in that, The top plate of the experimental chamber (1) is provided with a top viewing window (41) directly above the evaporation platform (2) and the condensation platform (3). The experimental chamber (1) has side windows (42) on the side plate on the side parallel to the distribution direction of the evaporation stage (2) and the condensation stage (3), respectively, at the position directly opposite the evaporation stage (2) and the condensation stage (3); on the inner side of the side plate on the other side parallel to the side plate, each side window (42) is provided with a set of background light sources (43).

4. The experimental system for evaporation, condensation, convection, and phase change heat transfer according to claim 1, characterized in that, The evaporation platform (2) includes an evaporation base (22), an evaporation base (23), and an evaporation base (24) arranged sequentially from top to bottom. The evaporation base (23) is provided with a droplet cavity (25) inside. The liquid injection connector (21) is provided on the side wall of the evaporation base (23) for injecting liquid experimental working fluid into the droplet cavity (25). The evaporation substrate (22) has a droplet outlet hole (26) penetrating the evaporation substrate (22) in the vertical direction at the center position. The evaporation base (23) has a droplet through hole (27) on the surface in contact with the evaporation base (23) corresponding to the droplet outlet hole (26) and communicating with the droplet cavity (25). The liquid experimental working medium passes through the droplet cavity (25), the droplet through hole (27) and the droplet outlet hole (26) in sequence to form droplets on the evaporation base (23). A heating component (28) is provided between the evaporation base (23) and the evaporation base (24), and the evaporation base (23) is in contact with the heating component (28). Through the heat conduction between the evaporation base (22) and the evaporation base (23), the droplets at the evaporation base (22) can be evaporated.

5. The evaporation and condensation convection and phase change heat transfer experimental system according to claim 4, characterized in that, A first sensor (291) is provided between the evaporation substrate (22) and the evaporation base (23). The sensing end of the first sensor (291) is located directly below the formed droplet. The experimental working medium can pass through the first sensor (291). The first sensor (291) is used to measure the change in the heat flow of the droplet. The evaporation base (23) is provided with at least two second sensors (292) near the evaporation substrate (22), such that the sensing end of the second sensor (292) is located directly below the formed droplet, and the sensing end of the second sensor (292) is not located inside the droplet cavity (25). The second sensor (292) is used to measure the temperature at different positions of the droplet. The evaporation base (23) is also provided with a third sensor (293), which is used to feed back the collected temperature of the evaporation base (23) to the evaporation temperature control module, and adjust the temperature of the heating component (28) through the evaporation temperature control module; A fourth sensor is also provided at the evaporation substrate (22), which is used to measure the temperature of the air near the droplet.

6. The experimental system for evaporation, condensation, convection, and phase change heat transfer according to claim 4, characterized in that, The evaporation substrate (22) has a disc-shaped structure. The surface of the evaporation substrate (22) that carries the droplets is provided with at least one annular groove (221) around the periphery of the droplet outlet (26). The evaporation substrate (22) has a vertically upward protruding edge (222) at the edge position to prevent the experimental working medium from overflowing from the evaporation substrate (22).

7. The evaporation and condensation convection and phase change heat transfer experimental system according to claim 4, characterized in that, The condensation platform (3) includes a heat conduction element (31) and a heat insulation layer (32) wrapped around the heat conduction element (31). The top of the heat conduction element (31) is exposed in the experimental chamber (1). The bottom of the heat conduction element (31) is provided with a refrigeration component (33), and the heat conduction element (31) is in contact with the refrigeration component (33), so that the temperature of the top of the heat conduction element (31) can be lower than the temperature inside the experimental chamber (1), thereby allowing the steam above the heat conduction element (31) to condense on the top of the heat conduction element (31).

8. The experimental system for evaporation, condensation, convection, and phase change heat transfer according to claim 7, characterized in that, The interior of the heat conduction element (31) is provided with a fifth sensor (341) near the top. The fifth sensor (341) is used to measure the change in heat flow rate of the droplets that drip from the vapor in the experimental chamber (1) onto the top of the heat conduction element (31) during the condensation process. The heat conduction component (31) is equipped with a sixth sensor (342) and a seventh sensor (343). The sixth sensor (342) is used to monitor the temperature of the heat conduction component (31), and the seventh sensor (343) is used to feed back the temperature of the heat conduction component (31) to the condensing temperature control module of the refrigeration component (33), and the condensing temperature control module adjusts the temperature of the refrigeration component (33).

9. An experimental method for evaporation and condensation convection and phase change heat transfer experiments, characterized in that, Evaporation and condensation experiments were conducted using the evaporation and condensation convection and phase change heat transfer experimental system according to any one of claims 4-8; multiple evaporation experiments or condensation experiments were conducted separately, or evaporation experiments and condensation experiments were conducted sequentially. The steps of the evaporation experiment include: Step 011: Create a sealed experimental chamber (1) environment for the evaporation experiment; Step 012: The liquid injection unit injects the experimental working medium into the evaporation platform (2), so that the experimental working medium overflows from the droplet outlet (26) of the evaporation base (22) and forms droplets that meet the experimental requirements in the evaporation base (23); Step 013: The evaporation temperature control module raises the temperature of the heating component (28), and heats the droplets formed at the evaporation base (22) through heat conduction between the evaporation base (23) and the evaporation substrate (22) until they evaporate to form steam; Step 014: During the droplet evaporation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal. Step 015: During the droplet evaporation process, adjust the experimental environment inside the experimental chamber (1) to observe the changes in the droplet evaporation rate, temperature and heat flow. The steps of the condensation experiment include: Step 021: Create a sealed experimental chamber (1) environment for the condensation experiment and fill the experimental chamber (1) with steam; Step 022, the condensation temperature control module lowers the temperature of the heat transfer element (31), so that the steam above the heat transfer element (31) can condense on the top of the heat transfer element (31) and form droplets; Step 023: During the steam condensation process, image data, temperature data, and heat flow data of the experiment are collected through observation equipment and sensors, and the relevant data are fed back to the data terminal. Step 024: During the steam condensation process, steam is injected into the experimental chamber (1) through the steam injection unit to meet the requirements of the condensation experiment for the steam environment; Step 025: During the steam condensation process, adjust the experimental environment inside the experimental chamber (1) to observe the changes in the droplet evaporation rate, temperature and heat flow.

10. The experimental method for evaporation and condensation convection and phase change heat transfer experiments according to claim 9, characterized in that, In evaporation experiments, if multiple evaporation experiments are performed individually; After multiple evaporation experiments, saturated vapor pressure will be generated in the experimental chamber (1). The saturated vapor in the experimental chamber (1) is extracted by the pumping unit, and fresh air is injected into the experimental chamber (1) by the air injection unit to regulate the pressure inside the experimental chamber (1). In the condensation experiment, In step 021, the steam environment generated by the evaporation experiment is used to carry out the condensation experiment, or steam is injected into the experimental chamber (1) through the steam injection unit in the absence of steam in the sealed chamber, so as to meet the requirements of the condensation experiment for the steam environment. In step 025, during the steam condensation process, fresh air is injected through an air injection unit to experimentally study the effect of non-condensable gas on the steam condensation process.

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