Method and device for detecting heat conductivity near melting point of phase change energy storage material

A phase change energy storage material and detection method technology, applied in the direction of material thermal development, etc., can solve problems such as difficulty in measuring heat flow, errors in thermal parameter values ​​of phase change materials, and inability to measure thermal conductivity of viscous liquids and solids, etc., to ensure authenticity effect

Inactive Publication Date: 2012-01-04
CENT SOUTH UNIV
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Problems solved by technology

Among them, the thermal calorimeter method can directly measure the thermal parameters of the material, but it is difficult to measure the heat flow during the test process, the accuracy is poor, and it cannot measure the phase change material under the condition of liquid convection; DTA and DSC technology can only measure the trace material (1 -10mg) for measurement, but there is a certain error between the trace test value and the thermal parameter value of the phase change material in practical applications; the transient hot wire method can simultaneously measure the thermal conductivity and thermal diffusivity of liquid substances, and the errors are not more than 5% and 50% respectively. %, but it is difficult to measure the thermal conductivity of conductive liquids, nor can it measure the thermal conductivity of viscous liquids and solids

Method used

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  • Method and device for detecting heat conductivity near melting point of phase change energy storage material
  • Method and device for detecting heat conductivity near melting point of phase change energy storage material
  • Method and device for detecting heat conductivity near melting point of phase change energy storage material

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Embodiment 1

[0057] Sodium nitrate test: In order to solve the error introduced by the difference between the experimental boundary conditions and the theoretical boundary conditions, this study introduces the "reverse-positive two-step calculation method". The first step is to obtain the "simple" experimental data of thermophysical properties according to the inverse problem of heat transfer and the analytical solution of the ideal model, and complete the experimental test part.

[0058] Experimental device such as figure 1 and figure 2 shown.

[0059] The sodium nitrate sample used in the test was analytically pure sodium nitrate produced by Tianjin Kemiou Chemical Reagent Co., Ltd., with a purity of ≥99.0% and a melting point of 307°C. The phase change chamber (double-layer quartz tube) is filled with solid sodium nitrate, and the sample is repeatedly melted and solidified to eliminate the holes in the solid sodium nitrate; before the test starts, the salt bath control system is conn...

Embodiment 2

[0070] Zinc bromide test: the sample is analytically pure zinc bromide produced by Tianjin Kemiou Chemical Reagent Co., Ltd., with a purity of ≥99.0% and a melting point of 394°C. Experimental device such as figure 1 and figure 2 shown.

[0071] In the first step, the phase change chamber (double-layer quartz tube) is filled with solid zinc bromide, and the sample is repeatedly melted and solidified to eliminate the holes in the solid zinc bromide; before the test starts, the salt bath control system is connected, and the temperature of the salt bath Maintain at 390°C, control the temperature of the iron block on the upper end surface at 390°C, and immerse the phase change chamber in a salt bath (pure lithium nitrate, salt bath range 280-500°C) until the temperature is stable; at t=0s, the iron block on the upper end face Suddenly raise the temperature to 474°C, the upper end of the molten salt to be tested begins to melt, and the phase interface gradually moves down; use t...

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Abstract

The invention discloses a method and a device for detecting heat conductivity near the melting point of a phase change energy storage material. The method comprises the following steps of: 1, calculating the approximate value of the heat conductivity near the melting point of the phase change energy storage material according to an analysis formula under the ideal phase change condition; and 2, introducing a numerical simulation correction method to obtain an experiment corrected value, namely the accurate value of the heat conductivity near the melting point of the phase change energy storage material. The method and the device for detecting the heat conductivity near the melting point of the phase change energy storage material are high in test result accuracy and solve the problems that the phase change material has a lattice change when temperature gradient is applied in the conventional measuring method, and the like.

Description

technical field [0001] The invention relates to a new thermal parameter tester and its test method, in particular to a detection method and detection device for thermal conductivity near the melting point of a phase-change energy storage material, especially suitable for phase-change materials near the melting point during melting and solidification Test field for thermal conductivity. Background technique [0002] Almost all test methods of thermal diffusivity and thermal conductivity, whether it is a steady-state method or an unsteady-state method, must apply a temperature gradient to the substance to be tested and maintain this temperature during the test. This will often change the original structure, crystal phase and thermophysical properties of the tested substance, making the test results lose their authenticity. Since there are no suitable measurement methods for thermal diffusivity and thermal conductivity near the melting point of solid-liquid phase change energy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/20
Inventor 周孑民梁艳南杨莺吴烨李远
Owner CENT SOUTH UNIV
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