Solid-liquid phase change material volume expansion rate testing device

Abstract

The embodiment of the invention provides a solid-liquid phase change material volume expansion rate testing device. The solid-liquid phase change material volume expansion rate testing device comprises a sample container, a liquid level sensor, a temperature control assembly and an upper computer. The sample container is suitable for placing a to-be-detected sample, and isolation liquid which is not fused with the to-be-detected sample is arranged above the to-be-detected sample. And the liquid level sensor is arranged in the isolation liquid and is suitable for measuring the liquid level of the isolation liquid. And the temperature control assembly is suitable for adjusting the temperature of the to-be-tested sample, so that the to-be-tested sample is subjected to phase change. The upper computer is configured to obtain the liquid level difference before and after the solid-liquid phase change of the to-be-detected sample based on the liquid level sensor and obtain the volume expansion rate caused by the solid-liquid phase change of the to-be-detected sample. Therefore, the problem that the measuring equipment is easy to damage due to contact between the liquid level sensor and the to-be-measured sample is avoided.

Description

Technical Field

[0001] This disclosure relates to the field of material volume expansion rate testing technology, specifically to a testing device for testing the volume expansion rate of solid-liquid phase change materials. Background Technology

[0002] Phase change materials (PCMs) typically undergo significant volume changes during solid-liquid phase transitions. Accurate measurement of their volume expansion rate is crucial for material formulation optimization, energy storage system structural design, and long-term operational reliability assessment. Currently, the main technical approaches for testing the volume expansion rate of PCMs fall into the following categories:

[0003] Classical hydrostatic methods, such as Archimedes' displacement method, calculate volume changes by measuring the change in buoyancy experienced by the material before and after a phase transition in the immersion liquid. However, this method has significant limitations: the operation is cumbersome, requiring multiple sampling and weighing; it cannot achieve continuous monitoring during the phase transition process; and it introduces significant measurement errors during the dynamic changes at the phase transition interface.

[0004] Optical measurement methods include laser displacement sensor methods and digital image correlation techniques. While these methods enable non-contact measurement, they have extremely high requirements for sample surface condition, optical transmittance, and environmental stability, resulting in high equipment costs. More importantly, for materials undergoing solid-liquid transitions during phase transitions, the specular reflection characteristics of the liquid surface can severely affect the stability of the measurement signal, leading to data distortion.

[0005] Thermomechanical analyzers: As commercial instruments, although they have high measurement accuracy, their sample chamber volume is limited, and they can only process trace samples at the milligram level. This has a significant scale difference from the macroscopic volume effect of phase change materials in practical applications, and the engineering guidance value of the test results is limited.

[0006] It is particularly important to note that the inherent corrosivity of hydrated salt phase change materials, which have significant application value, poses a severe challenge to measuring instruments. In existing contact measurement methods, direct contact between the sensor probe and the material can lead to probe corrosion, signal drift, and even permanent damage, seriously affecting measurement accuracy and equipment lifespan. Although some studies have attempted to use protective coatings, the presence of the coating itself alters the sensor's sensitivity and dynamic response characteristics, introducing non-negligible systematic errors.

[0007] Therefore, developing a device and method for measuring volume expansion rate that can effectively isolate corrosive media, achieve continuous monitoring throughout the entire process, ensure measurement accuracy, and be applicable to macroscopic samples has become a pressing technical challenge in the field of phase change materials research. Summary of the Invention

[0008] In view of this, the embodiments of this disclosure provide a device for testing the volume expansion rate of solid-liquid phase change materials, which can avoid the problem of easy damage to the measuring equipment due to the corrosiveness of phase change materials.

[0009] This disclosure provides an embodiment of a device for testing the volumetric expansion rate of solid-liquid phase change materials, comprising: a sample container, a liquid level sensor, a temperature control component, and a host computer. The sample container is suitable for holding the sample to be tested, and an immiscible insulating liquid is disposed above the sample. The liquid level sensor, disposed in the insulating liquid, is suitable for measuring the liquid level of the insulating liquid. The temperature control component is suitable for adjusting the temperature of the sample to induce a phase change. The host computer is configured to calculate the volumetric expansion rate of the sample caused by the solid-liquid phase change based on the liquid level difference obtained by the liquid level sensor before and after the solid-liquid phase change.

[0010] According to embodiments of this disclosure, a bath is also included, the bath containing a thermally conductive liquid. A sample container is surrounded by the thermally conductive liquid. A temperature control component regulates the temperature of the sample to be tested by adjusting the temperature of the thermally conductive liquid.

[0011] According to embodiments of this disclosure, the bottom of the sample container is in direct contact with the bottom of the bath, so that the heat-conducting liquid only surrounds the periphery of the sample container.

[0012] According to embodiments of this disclosure, the bath tub employs a double-layer insulation structure.

[0013] According to embodiments of this disclosure, the temperature control component includes a heater and a cooler; the heater and cooler are adapted to regulate the temperature of the heat-conducting liquid, thereby indirectly regulating the temperature of the sample to be tested.

[0014] According to embodiments of this disclosure, the temperature control assembly further includes a temperature controller, which includes a second temperature sensor and a controller. The second temperature sensor is disposed within the bath and is suitable for measuring the temperature of the heat-conducting liquid. The controller is configured to accept a preset temperature as input. It is adapted to receive data from the second temperature sensor and control the operation of the heater and cooler based on the preset temperature and the second temperature sensor data.

[0015] According to embodiments of this disclosure, the corrected volume expansion rate of the sample under test due to the solid-liquid phase transition is obtained based on the temperature of the thermally conductive liquid measured by the second temperature sensor, using the following formula:

[0016] ;

[0017] Where β is the volume expansion rate caused by the solid-liquid phase transition of the sample after correction, A is the cross-sectional area of ​​the sample container, Δh is the change in liquid level of the isolation liquid measured by the liquid level sensor, V0 is the initial volume of the sample, and α oil h is the coefficient of thermal expansion of the insulating liquid.oil The initial height of the isolated liquid is given by ΔT, which is the temperature change relative to the initial temperature measured by the second temperature sensor.

[0018] According to embodiments of this disclosure, a first temperature sensor and a multi-channel data logger are also included. The first temperature sensor is disposed in the sample to be tested and is suitable for measuring the temperature of the sample. The multi-channel data logger is suitable for acquiring and recording data from the first temperature sensor and the liquid level sensor. A host computer is communicatively connected to the multi-channel data logger. The host computer is also configured to generate visualization images and test reports based on the data recorded by the multi-channel data logger.

[0019] According to embodiments of this disclosure, the visualized image includes at least one of temperature-time curve, liquid level-time curve, volume change-time curve, and volume expansion rate-temperature curve; the test report includes at least one of test conditions, sample information, raw data table, key curve, maximum volume expansion rate, phase change onset temperature, phase change range, and phase change termination temperature.

[0020] In this embodiment, an isolating liquid separates the level sensor from the sample. A temperature control component regulates the temperature of the sample, causing a solid-liquid phase transition and resulting in a volume change. The level sensor measures the level of the isolating liquid. Then, a host computer calculates the volume expansion rate caused by the solid-liquid phase transition based on the liquid level difference, the sample container cross-sectional area, and the initial volume of the sample. This avoids the problem of measurement equipment being easily damaged due to the corrosiveness of the phase change material. Attached Figure Description

[0021] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0022] Figure 1 The schematic diagram illustrates the principle of a testing device for the volume expansion rate parameter of a phase change material.

[0023] Figure 2 A simplified schematic diagram of a testing apparatus for the volume expansion rate parameter of a phase change material is shown.

[0024] The meanings of the reference numerals in the attached figures are as follows:

[0025] 1. Sample to be tested; 2. Sample container; 3. Isolation liquid; 4. Temperature control component; 41. Heater; 42. Refrigerator; 43. Controller; 5. Thermally conductive liquid; 6. First temperature sensor;

[0026] 7. Liquid level sensor; 8. Bath tank; 9. Multi-channel data logger; 10. Host computer. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0031] Figure 1 The schematic diagram illustrates the principle of a device for testing the volumetric expansion rate parameter of a material.

[0032] Figure 2 A simplified schematic diagram of a testing apparatus for the volume expansion rate parameter of a phase change material is shown.

[0033] To address the corrosion problem of measuring instruments caused by phase change materials, especially hydrated salt phase change materials, in related technologies, this disclosure provides a testing device for the volumetric expansion rate parameter of a material, such as... Figure 1As shown, the system includes: a sample container 2, a liquid level sensor 7, a temperature control component 4, and a host computer 10. The sample container 2 is used to hold the sample 1 to be tested, and a non-miscible insulating liquid 3 is placed above the sample 1. The liquid level sensor 7 is located in the insulating liquid 3 and is used to measure the liquid level of the insulating liquid 3. The temperature control component 4 is used to adjust the temperature of the sample 1 to induce a solid-liquid phase transition. The host computer 10 is configured to calculate the volume expansion rate caused by the solid-liquid phase transition of the sample based on the liquid level difference obtained by the liquid level sensor 7 before and after the solid-liquid phase transition.

[0034] In this implementation, the isolation liquid 3 isolates the sample 1 to be tested from the level sensor 7. The level sensor 7 indirectly obtains the volume change data of the sample 1 to be tested by measuring the liquid level change of the isolation liquid 3. This avoids corrosion that may occur due to direct contact between the level sensor 7 and the sample 1 to be tested, thereby avoiding signal drift or even permanent damage, and improving the accuracy of measurement and the life of the equipment.

[0035] Specifically, the volume expansion rate caused by the solid-liquid phase transition of the sample under test can be calculated using the following formula:

[0036]

[0037] Where β is the volume expansion rate caused by the solid-liquid phase transition of the sample 1, A is the cross-sectional area of ​​the sample container 2 (which is known beforehand), Δh is the change in liquid level of the isolation liquid 3 measured by the liquid level sensor 7, and V0 is the initial volume of the sample 1. The product of A and Δh is equal to the volume change of the sample 1.

[0038] In some illustrative embodiments, the sample container 2 can be cylindrical, cuboid, or similar shapes. Preferably, the sample container 2 is cylindrical, as the cylindrical shape allows for more uniform heating of the sample 1 being tested when heated from all sides.

[0039] In some illustrative embodiments, the sample container 2 is made of corrosion-resistant metals such as glass or stainless steel. This improves the durability of the sample container 2.

[0040] In some illustrative embodiments, the inner wall of the sample container 2 is constructed as a smooth inner wall to reduce liquid adhesion, thereby reducing errors caused by liquid adhesion and improving the accuracy of the testing device.

[0041] In some illustrative embodiments, the sample 1 to be tested is a solid-liquid phase change material, and the measurement process involves a two-phase state of solid and liquid. During the measurement process, the density of the isolating liquid 3 is always less than the density of the sample 1 to ensure that the isolating liquid 3 is always above the sample 1, thereby isolating the level gauge from the sample 1. The isolating liquid 3 needs to be a material that is incompatible with the sample 1 to effectively transmit volume changes and also to isolate corrosion. Silicone oil can be used as the isolating liquid 3.

[0042] In some illustrative embodiments, it is understood that the isolating liquid 3 forms a liquid isolation layer above the sample 1 to be tested. Preferably, the thickness of the liquid isolation layer is 5-20 mm. This reduces the impact of its own mass and convection on the measuring device while ensuring effective isolation. An excessively thick liquid layer may introduce additional interference due to its own heat capacity and possible convection, while an excessively thin layer may lose its isolation effect.

[0043] According to embodiments of this disclosure, the level sensor 7 is selected from a level transmitter to improve testing accuracy. The level transmitter can be of hydrostatic or capacitive type. The measurement accuracy is not less than ±0.1%FS (Full Scale). It is understood that the level sensor 7 is disposed in the isolating liquid 3, which does not undergo phase change. This avoids corrosion of the sensor by the phase change material due to contact between the level sensor and the sample being measured, thus improving the accuracy of the measurement signal.

[0044] In some illustrative embodiments, to further improve durability, the level transmitter probe portion may be made of corrosion-resistant materials, such as 316L stainless steel or a polytetrafluoroethylene coating.

[0045] According to embodiments of this disclosure, the material volume expansion rate testing apparatus further includes a bath 8. The bath 8 contains a thermally conductive liquid 5, and the sample container 2 is disposed inside the bath 8 and surrounded by the thermally conductive liquid 5. A temperature control component 4 adjusts the temperature of the sample 1 to be tested by regulating the thermally conductive liquid 5. The thermally conductive liquid 5 can be an aqueous solution of ethylene glycol.

[0046] In this implementation, a bath 8 is provided, and the sample container 2 is placed inside the bath 8 and surrounded by a thermally conductive liquid 5. The temperature control component 4 indirectly regulates the temperature of the sample 1 to be tested through the thermally conductive liquid 5. The sample container 2 surrounded by the thermally conductive liquid 5 ensures that the sample 1 to be tested is heated evenly.

[0047] According to an embodiment of this disclosure, the bottom of the sample container 2 is in direct contact with the bottom of the bath 8, so that the heat-conducting liquid 5 only surrounds the periphery of the sample container 2.

[0048] In this implementation, the sample 1 under test only transfers heat through its periphery, and neither the upper nor lower side of the sample 1 under test is heated, resulting in more uniform heating.

[0049] In some illustrative embodiments, the bath 8 employs a double-layer insulation structure to isolate ambient heat and avoid interference from external ambient temperature. Furthermore, the bottom of the sample container 2 is in direct contact with the bottom of the bath 8, thus isolating the bottom of the sample container 2 from external ambient heat and preventing interference from the external environment.

[0050] According to embodiments of this disclosure, the temperature control component 4 includes a heater 41 and a cooler 42; the heater 41 and the cooler 42 are adapted to regulate the temperature of the heat-conducting liquid 5, thereby indirectly regulating the temperature of the sample 1 to be tested.

[0051] In this embodiment, heater 41 can conduct heat to the liquid 5, thereby indirectly heating the sample 1 and increasing its temperature. As the temperature rises, the sample 1 changes from a solid to a liquid state. The volume change of the sample 1 during this transition can be measured, and the volume expansion rate resulting from the solid-liquid phase transition can be calculated. Similarly, cooler 42 lowers the temperature of the sample 1, causing it to solidify from a liquid state. The volume change of the sample 1 during this transition can then be measured. The combined action of heater 41 and cooler 42 allows this measuring device to also measure the volume change during the liquid-to-solid transition and calculate the volume expansion rate.

[0052] According to embodiments of this disclosure, the temperature control assembly 4 further includes a temperature controller 43, which includes a second temperature sensor and a controller 43. The second temperature sensor is disposed within the bath 8 and is suitable for measuring the temperature of the heat-conducting liquid 5. The controller 43 is configured to accept a preset temperature as input. It is adapted to receive data from the second temperature sensor and control the operation of the heater 41 and the cooler 42 based on the preset temperature and the data from the second temperature sensor.

[0053] In this implementation, the second temperature sensor in the temperature control component 4 can measure the temperature of the heat-conducting liquid 5 in the bath 8. The controller 43 has a built-in temperature control program, in which the user can preset the temperature, including preset temperature changes and the rate of temperature change. The temperature controller 43 controls the operation of the heater 41 or the cooler 42, while simultaneously monitoring the temperature of the heat-conducting liquid 5 through the second temperature sensor and feeding the temperature back to the controller 43. The controller 43 then compares the measurement data from the second temperature sensor with the preset temperature and adjusts the operating status of the heater 41 and the cooler 42 accordingly. This includes controlling whether the heater 41 and the cooler 42 are operating, as well as controlling the operating power of the heater 41 and the cooler 42.

[0054] Furthermore, the second temperature sensor is a platinum resistance thermometer, preferably Pt100 (Platinum, abbreviated as Pt). The controller 43 incorporates a multi-segment temperature control program based on actual usage, employing a PID (Proportional-Integral-Derivative) control method. This allows for the control of the temperature of the heat-conducting liquid 5 within the bath 8, with a controllable temperature range from -20°C to 150°C and a control accuracy of ±0.1°C, ensuring that the phase change material can undergo a complete phase change temperature cycle at a preset rate.

[0055] According to an embodiment of this disclosure, based on the temperature of the thermally conductive liquid (5) measured by the second temperature sensor, the corrected volume expansion rate caused by the solid-liquid phase transition of the sample 1 to be tested is obtained based on the following formula:

[0056] ;

[0057] Where β is the volume expansion rate caused by the solid-liquid phase transition of the sample 1 after correction, A is the cross-sectional area of ​​the sample container 2, Δh is the change in liquid level of the isolation liquid 3 measured by the liquid level sensor 7, V0 is the initial volume of the sample 1, and α oil h is the coefficient of thermal expansion of the insulating liquid 3. oil Let ΔT be the initial height of the isolation liquid 3, and ΔT be the temperature change of the temperature data measured by the second temperature sensor (5) relative to the initial temperature. In this way, the influence of the volume expansion rate of the test sample 1 caused by the volume change of the isolation liquid 3 itself with temperature change is eliminated by correction, and the accuracy of the measured volume expansion rate of the test sample 1 caused by solid-liquid phase transition is further improved.

[0058] According to embodiments of this disclosure, the material volume expansion rate testing device further includes a first temperature sensor 6 and a multi-channel data logger 9. The first temperature sensor 6 is disposed in the sample 1 to be tested and is suitable for measuring the temperature of the sample 1. The multi-channel data logger 9 is communicatively connected to the first temperature sensor 6 and the liquid level sensor 7 to acquire and record data from the first temperature sensor 6 and the liquid level sensor 7. The host computer 10 is also configured to generate a visualization image and a test report based on the data recorded by the multi-channel data logger (9).

[0059] In some embodiments of this application, the host computer 10 includes a data processing module, a visualization module, and a report generation module. The data processing module is suitable for processing data recorded by the multi-channel data logger 9. The visualization module is suitable for generating visual images from the processed data. The report generation module is suitable for generating test reports.

[0060] In this implementation, the multi-channel data logger 9 has multiple independent acquisition channels, enabling simultaneous acquisition and storage of data from the first temperature sensor 6 and the liquid level sensor 7. This ensures synchronized recording of liquid level and temperature data, and the sampling frequency of the multi-channel data logger 9 is no less than 1 Hz. Furthermore, the multi-channel data logger 9 can export the stored data to the host computer 10 for further processing and analysis. The data processing module in the host computer 10 processes the received data, and after processing, the data is visualized to generate a visual image. The report generation module generates a test report based on the data before and after processing. Thus, the relevant properties of the material under test can be intuitively observed through the visual image, and the test report can be obtained through the report generation module for further research and analysis.

[0061] In some illustrative embodiments, after receiving data from the multi-channel data logger 9, the data processing module first corrects the data using built-in algorithms, including but not limited to thermal expansion compensation. Then, based on a preset physical model and a visualization module, it calculates and plots the volume expansion rate curve in real time, and finally generates a test report with one click.

[0062] According to embodiments of this disclosure, the visualized images include at least one of temperature-time curves, liquid level-time curves, volume change-time curves, and volume expansion rate-temperature curves. The test report includes at least one of test conditions, sample information, raw data tables, key curves, maximum volume expansion rate, phase change onset temperature, and phase change termination temperature.

[0063] In some embodiments of this application, the temperature-time curve is a curve of data collected by the first temperature sensor 6 versus time, reflecting the temperature change of the sample 1 under test over time. The liquid level-time curve is a curve of data collected by the liquid level sensor 7 versus time, reflecting the liquid level change of the isolation liquid 3 over time. The volume change of the sample 1 under test is calculated based on the liquid level change of the isolation liquid 3, and the volume change-time curve is a curve of the volume change of the sample 1 under test versus time, reflecting the volume change of the sample 1 under test over time. The volume expansion rate of the sample 1 under test is calculated based on the volume change rate of the sample 1 under test, and the volume expansion rate-temperature curve is a curve of the volume expansion rate of the sample 1 under test versus time, reflecting the volume expansion rate of the sample 1 under test over time.

[0064] In this embodiment, users can not only intuitively observe direct data such as temperature and liquid level collected by the sensor, but also data that intuitively reflects the performance of the sample 1 under test, such as volume change and volume expansion rate. This facilitates a direct understanding of the performance and state of the sample 1 under test. Preferably, the host computer 10 simultaneously displays the temperature-time curve, liquid level-time curve, volume change-time curve, and volume expansion rate-temperature curve for user observation. Furthermore, through data processing by the built-in program, a test report can be generated with one click, including at least one of the following: test conditions, sample information, raw data table, key curves, maximum volume expansion rate, phase transition initiation temperature, and phase transition termination temperature. Preferably, it includes all of the above. Thus, preliminary data analysis and report generation can be achieved for further analysis and research.

[0065] In some embodiments of this application, the test conditions include the temperatures of the hot and cold sources during the test of volumetric expansion rate. Sample information includes the name and mass of the sample to be tested. The raw data table includes liquid level change data during heating / cooling at different times, and temperature data of the sample to be tested at different times. Key curves include the temperature-time curve, liquid level-time curve, volume change-time curve, and volumetric expansion rate-temperature curve. The maximum volumetric expansion rate is the volumetric expansion rate calculated when the volume change of sample 1 is at its maximum. The phase transition onset temperature is the temperature at which the phase transition begins, i.e., the first inflection point of the temperature-time curve. The phase transition range refers to the temperature region where the material undergoes a near-isothermal phase transition, i.e., the temperature range in the temperature-time curve that is close to horizontal. The phase transition termination temperature is the temperature at which the phase transition ends, i.e., the second inflection point of the temperature-time curve.

[0066] According to embodiments of this disclosure, a method for testing the volumetric expansion rate of materials is also provided, applicable to solid-liquid phase change materials, particularly hydrated salt phase change materials. This method utilizes the material volumetric expansion rate testing apparatus described in the embodiments of this application. The steps are as follows:

[0067] S1: Inject the heat-conducting liquid 5 into the bath 8; place the sample to be tested 1 into the sample container 2;

[0068] S2: Inject isolation liquid 3 into sample container 2; place liquid level sensor 7 into isolation liquid 3;

[0069] S3: Set the preset temperature and start the temperature control component 4;

[0070] S4: Start the first temperature sensor 6, liquid level sensor 7, multi-channel data logger 9 and host computer 10 to continuously record liquid level data and temperature data;

[0071] S5: After the preset temperature program is completed, the multi-channel data logger 9 completes data acquisition, and the host computer 10 processes the data and generates a test report.

[0072] In some illustrative embodiments, step S1 involves injecting a thermally conductive liquid 5 into the bath 8 to a specified height, followed by adding a measured amount of the sample 1 to be tested. The height of the thermally conductive liquid 5 should be higher than the height of the sample 1 to be tested, so that the thermally conductive liquid 5 can surround the sample 1. Typically, the height of the thermally conductive liquid 5 is one-third of the height of the sample container 2.

[0073] In some illustrative embodiments, step S2 involves injecting the isolation liquid 3 slowly to avoid generating air bubbles and to ensure a smooth liquid surface.

[0074] In some illustrative embodiments, in step S3, a preset temperature is set in the program of the temperature control component 4 according to the characteristics of the material to be tested. The preset temperature includes a minimum temperature, a maximum temperature, and heating and cooling rates. Taking hydrated salt materials as an example, the temperature can start 5°C below the phase transition point, be increased at a rate of 0.5°C / min to 10°C above the phase transition point, held at that temperature for a period of time, and then cooled at the same rate to complete a complete phase transition cycle. Then the temperature control component 4 is started. It can be understood that after the temperature control component 4 is started, the changes in sensor data can be observed from the multi-channel data logger 9 and the host computer 10.

[0075] In some illustrative embodiments, step S4 involves activating the first temperature sensor 6, the liquid level sensor 7, and the multi-channel data logger 9 to acquire and record the initial state values.

[0076] In some illustrative embodiments, in step S5, after the preset temperature program is completed, the sample 1 to be tested has also undergone a phase change cycle. At this time, the host computer 10 processes all the data and generates a test report.

[0077] In some illustrative embodiments, the above calculation methods and formulas have been built into the host computer 10 and / or the multi-channel data logger 9.

[0078] The following is an illustrative example:

[0079] The volume expansion rate of hydrated salt phase change materials at phase change temperatures ranging from 28°C to 32°C was tested.

[0080] Device configuration:

[0081] Sample container 2 is a cylindrical glass container with an inner diameter of 50 mm. The level transmitter is a hydrostatic type with an accuracy of ±0.05%FS, and the probe material is 316L stainless steel. The isolating liquid 3 is silicone oil with a layer thickness of 10 mm and a density of 0.96 g / cm³. The multi-channel data logger 9 is an eight-channel type with a sampling frequency of 1 Hz.

[0082] S1: Pour ethylene glycol aqueous solution thermally conductive liquid 5 into bath 8 to a height of 30 mm. Place 150 g of hydrated salt sample to be tested into sample container 2.

[0083] S2: Inject silicone oil isolation liquid 3 into sample container 2 to form a silicone oil isolation layer with a height of 10mm. Place the level transmitter into the silicone oil isolation layer.

[0084] S3: Set temperature program: Increase the temperature from 20℃ to 50℃ at a rate of 0.5℃ / min, hold the temperature for 20 minutes, and then decrease the temperature to 20℃ at a rate of 0.5℃ / min, so that the phase change material undergoes a complete melting and solidification process.

[0085] S4: Start the first temperature sensor 6, level transmitter, multi-channel data logger 9, and host computer 10 to continuously record silicone oil level and temperature data. At this time, the level-time and temperature-time data stored in the data logger are sent to the host computer 10. The data processing module in the host computer 10 processes the data, and the visualization module plots the volume change-time curve and the volume expansion rate-temperature curve.

[0086] S5: After the preset temperature program has been executed, the multi-channel data logger 9 has completed data acquisition, and the host computer 10 processes the data and generates a test report. The test report includes test conditions, sample information, raw data table, key curves, maximum volume expansion rate, phase transition initiation temperature, and phase transition termination temperature.

[0087] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are identified by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0088] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A device for testing the volume expansion rate of solid-liquid phase change materials, characterized in that, include: The sample container (2) is suitable for placing the sample to be tested (1), and an isolation liquid (3) that does not mix with the sample to be tested (1) is placed above the sample to be tested (1). A liquid level sensor (7) is disposed in the isolation liquid (3) and is suitable for measuring the liquid level of the isolation liquid (3); Temperature control component (4) is used to adjust the temperature of the sample to be tested (1) so that the sample to be tested (1) undergoes a solid-liquid phase transition; as well as The host computer (10) is configured to obtain the liquid level difference before and after the solid-liquid phase change of the sample under test based on the liquid level sensor (7), and calculate the volume expansion rate caused by the solid-liquid phase change of the sample under test.

2. The device for testing the volume expansion rate of solid-liquid phase change materials according to claim 1, characterized in that, It also includes a bath (8) containing a thermally conductive liquid (5); the sample container (2) is surrounded by the thermally conductive liquid (5); the temperature control component (4) adjusts the temperature of the sample (1) to be tested by adjusting the temperature of the thermally conductive liquid (5).

3. The solid-liquid phase change material volume expansion rate testing device according to claim 2, characterized in that, The bottom of the sample container (2) is in direct contact with the bottom of the bath (8) so that the heat-conducting liquid (5) only surrounds the periphery of the sample container (2).

4. The solid-liquid phase change material volume expansion rate testing device according to claim 3, characterized in that, The bath tub (8) adopts a double-layer heat insulation structure.

5. The apparatus for testing the volumetric expansion rate of solid-liquid phase change materials according to any one of claims 2-4, characterized in that, The temperature control component (4) includes a heater (41) and a cooler (42); the heater (41) and the cooler (42) are adapted to regulate the temperature of the heat-conducting liquid (5), thereby indirectly regulating the temperature of the sample (1) to be tested.

6. The device for testing the volume expansion rate of solid-liquid phase change materials according to claim 5, characterized in that, The temperature control component (4) further includes a temperature controller (43), the temperature controller (43) comprising: The second temperature sensor is installed inside the bath (8) and is suitable for measuring the temperature of the heat-conducting liquid (5); The controller is configured to input a preset temperature; the controller is adapted to receive data from the second temperature sensor and control the heater (41) and the cooler (42) to operate according to the preset temperature and the second temperature sensor data.

7. The device for testing the volume expansion rate of solid-liquid phase change materials according to claim 6, characterized in that, Based on the temperature of the thermally conductive liquid (5) measured by the second temperature sensor, the corrected volume expansion rate caused by the solid-liquid phase transition of the sample (1) is obtained according to the following formula: ； Wherein, β is the volume expansion rate caused by the solid-liquid phase transition of the sample to be tested (1) after correction, A is the cross-sectional area of ​​the sample container (2), Δh is the liquid level change of the isolation liquid (3) measured by the liquid level sensor (7), V0 is the initial volume of the sample to be tested (1), and α oil h is the coefficient of thermal expansion of the insulating liquid (3). oil ΔT is the initial height of the isolation liquid (3), and ΔT is the temperature change of the temperature data measured by the second temperature sensor (5) relative to the initial temperature.

8. The device for testing the volume expansion rate of solid-liquid phase change materials according to claim 2, characterized in that, Also includes: A first temperature sensor (6) is disposed in the sample to be tested (1) and is suitable for measuring the temperature of the sample to be tested (1); A multi-channel data logger (9) is suitable for acquiring and recording data from the first temperature sensor (6) and the liquid level sensor (7); The host computer (10) is also configured to generate visualization images and test reports based on the data recorded by the multi-channel data logger (9).

9. The device for testing the volume expansion rate of solid-liquid phase change materials according to claim 8, characterized in that, The visualization image includes at least one of the following: temperature-time curve, liquid level-time curve, volume change-time curve, and volume expansion rate-temperature curve; the test report includes at least one of the following: test conditions, sample information, raw data table, key curves, maximum volume expansion rate, phase change onset temperature, phase change range, and phase change termination temperature.

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