Dynamic measurement of thermophysical properties of molten salt and error correction method

Since the data of thermophysical properties of high temperature phase-change heat storage materials are limited and the measurement methods are lacking,an apparatus based on the Stefan model and Lamvik model was designed to determine dynamically the thermophysical properties of high-temperature molten salt at the melting point based on the relationship between the speed of the moving phase-transition interface and the thermophysical properties of liquid-solid phase in the melting and solidification processes.An error correction method was put forward to correct the result by simulating dynamic testing processes and implemented numerically by using user defined functions(UDFs).Some samples of sodium nitrate,potassium nitrate and zinc bromide with known thermophysical properties were measured and the results were corrected.Compared the experimental results and corrective results of thermal conductivity and thermal diffusivity of sodium nitrate and potassium nitrate with the values recommended in literature,the errors are less than 5%.The results of three molten salts show a significantly smaller error between the calculation and the test result after the correction than before the correction,and the thermal conductivity confirms that the error correction method significantly reduces the error from non-one-dimensional heat conduction and unstable temperature boundary conditions.The combination of dynamic measurement with the error correction can improve the accuracy of apparatus and reduce the requirements for testing devices.The reliability of the method is confirmed experimentally.This study may offer basic data and theoretical foundation for further investigation on thermophysical properties of other high temperature molten salts.