Mathematical Modeling of Heat and Mass Transfer in Capillary-Porous Structure of Heat Accumulators with Wet Sand

To enhance the operational stability of heat generators utilizing renewable energy sources, as well as to store excess heat produced by large power thermal power plants during the summer period, it is pertinent to develop cost-effective and efficient heat accumulators. This necessitates experimental studies and mathematical modeling to select new materials with highly efficient heat-accumulating properties. The aim of this paper is to conduct mathematical modeling of heat and mass transfer processes with phase transition in a saturated liquid within a capillary-porous structure. A mathematical model of two-phase coolant flow in a capillary-porous structure was developed, along with the creation of an algorithm and calculation program. A numerical study of heat and mass transfer processes in an element of a capillary-porous structure, which is a cylinder filled with wet sand with heat input, was carried out. The comparison of calculation results with experimental data obtained by Kent S. Udell demonstrated the adequacy of the developed mathematical model, which can be applied for the development of heat accumulators made from capillary-porous materials (such as sand) with high heat-accumulating characteristics due to the phase transition of the coolant.