Research on the stress characteristics of packed-bed molten salt heat storage tanks based on thermo-mechanical coupling numerical calculation method

This paper establishes a thermo-mechanical coupling numerical model of a packed-bed molten salt heat storage tank. Based on this model, the dynamic variation characteristics of the temperature and stress on the tank wall during multiple charging-discharging cycles are studied. The research results show a stress concentration phenomenon at the bottom end of the tank wall plate. After 29 cycles, the peak stress will be higher than the material yield strength, causing plastic yielding of the wall surface. Moreover, with the progress of the charging-discharging cycles, the packed-bed heat storage tank may experience low-cycle fatigue fracture failure caused by high stress (greater than the yield strength). An effective reference method for the dynamic stress fatigue life assessment of packed-bed heat storage tanks will be provided in this research.