Yuan Xiugan

Three-dimensional heat transfer analysis for a thermal energy storage canister

High temperature latent thermal storage is one of the critical techniques for a solar dynamic power system. This paper presents results from heat transfer analysis of a phase change salt containment canister. A three-dimensional analysis program is developed to model heat transfer in a PCM canister. Analysis include effects of asymmetric circumference heat flux, conduction in canister walls, liquid PCM and solid PCM, void volume change and void location, and conduction and radiation across PCM vapor void. The PCM phase change process is modeled using the enthalpy method and the simulation results are compared with those of other two-dimensional investigations. It’s shown that there are large difference with two-dimensional analysis, therefore the three-dimensional model is necessary for system design of high temperature latent thermal storage.

A new computation method for solidification process in a finite, initially overheated slab

An approximate theory is presented for solidification in a finite, initially overheated slab in which one wall is insulated and the other is subject to an instantaneous temperature drop below the freezing point. The simple expressions for the position of the phase change front as a function of time are derived. The results are compared with experimental data, numerical and approximate solutions as well as exact solution presented in other literature, and good agreement is attained. It is shown that the approximate method proposed herein is also valid for phase change problems with large Stefan numbers and different boundary conditions.