Measuring device and method for phase interface of composite phase change material melting/solidifying process based on thermochromic liquid crystal

Abstract

The invention discloses a measuring device and method for a phase interface of a composite phase change material melting / solidifying process based on a thermochromic liquid crystal. The device is applied to the field of thermal storage of a composite phase change material with high thermal conductivity and is composed of a hot end, a cold end, a testing main body and a data acquisition system, wherein the testing main body is internally provided with a thermal storage cavity, a thermochromic liquid crystal layer, an isolation layer and a vacuum glass layer. The visualized measurement of the wall surface temperature of the thermal storage cavity and a solid liquid interface of the composite phase change material is realized by utilizing the characteristics of reversible thermochromism, hightemperature resolution, high spatial resolution and high response speed of the thermochromic liquid crystal layer; by utilizing the isolation layer, the response speed of the thermochromic liquid crystal is increased, and influences to thermal transfer in a thermal storage body are reduced; the conflict between visualized measurement and device thermal insulation is solved by utilizing the vacuumglass layer; and the temperature of the hot end / the cold end is monitored by utilizing the data acquisition system. The measuring device and method are used for realizing the visualized measurement of a composite phase change material melting / solidifying phase interface and a temperature field change process while realizing thermal insulation and is conductive to the research of a thermal transfer process of the composite phase change material in a differential thermal square cavity.

Description

technical field [0001] The invention belongs to the field of heat storage of high thermal conductivity composite phase change materials, and in particular relates to a phase interface measurement device and method for the melting / solidification process of composite phase change materials based on thermochromic liquid crystals. Background technique [0002] Thermal energy not only widely exists in nature in the form of solar energy and geothermal energy, but also is produced in low-grade forms in high-energy industries such as iron and steel metallurgy, cement building materials, and petrochemical industries. Therefore, if thermal energy can be effectively stored and utilized, it is an effective means to realize energy source and improve utilization rate. [0003] Solid-liquid phase change materials have the advantages of low cost, constant temperature during heat storage and heat release, small thermal expansion rate, stable physical and chemical properties, etc., and are wi...

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Problems solved by technology

[0004] However, in the study of the actual heat transfer performance of the composite phase change material in the heat storage cavity, it was found that the addition of nanoparticles made the solid-liquid two-phase interface of the composite phase change material during the melting / solidification process invisible, so it was impossible to use traditional direct observation. A visualization method to determine the phase interface position and quantitatively analyze the heat transfer performance of the thermal storage cavity

Most of the current experimental devices use the method of arranging a large number of thermocouples in the cavity to measure the position of the phase interface, but this dense and intrusive measurement method will seriously interfere with the melting / solidification process of the composite phase change material, and it is very dependent on the quality of the thermocouples

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