Thermal analysis and performance improvement of heat transfer in sample cell of Sieverts apparatus

Abstract

In a Sieverts apparatus, the poor heat transfer performance of a sample cell leads to inaccuracy in kinetics test of hydrogen storage materials. Consequently, the analysis of heat transfer of the reaction process in the sample cell is essential. However, it is difficult for traditional detection methods to track the physical and chemical dynamic changes in the sample cell. In this paper, the finite element method was used to simulate the reaction process in the sample cell. A two-dimensional numerical model was designed to characterize the hydrogen absorption process in order to investigate the link between the heat transfer performance of the sample cell and the reaction kinetics. It was found that the reaction kinetics would be close to the intrinsic kinetics of the materials as its amount decreased. However, the decreased amount of hydrogen storage materials had a restricted effect on the increase of the reaction rate. The relevant amount of hydrogen storage material was recommended based on the comprehensive analysis of this study. In addition, the improvement of the thermal conductivity of the MH reaction bed and sample cell material improved the heat transfer performance to a certain extent. Finally, the relationship among the amount of hydrogen storage material, thermal conductivity and absorption time was established through the simulation analysis, which provided some schemes for optimizing the reaction kinetics testing accuracy of Sieverts apparatus.