Method for Calculating the Processes of Melting and Solidification of Heat-Accumulating Materials in Fine Capsules

Abstract

We propose a new method for calculating the processes of melting and solidification of heat-accumulating materials placed inside small-sized elastic capsules of symmetric form. The specific feature of the method is the simultaneous solution of the heat conduction equation joined for both phases and the equation for the rate of change in the mass fraction of the new phase in the layer between two neighboring nodes of a stationary computational mesh. The method permits using explicit finite-difference schemes for continuous calculations of the nonlinear heat conduction equation without loss of stability at weak and alternating external heat flows, as well as in the presence of several phase transition zones in the capsule. The paper presents the results of a test solution of the two-phase Stefan problem for an unbounded plate and the results of calculations for spherical capsules with n-paraffin in one regenerative convective heat cycle.