Effects of employing various PCM layers with different thicknesses on the heat transfer features within an annulus tube heat exchanger
Dr. Suvash C. Saha
School of Mechanical and Mechatronic Engineering
University of Technology, Sydney
PO Box 123, Broadway
NSW 2007 Australia
The use of latent heat storage materials containing phase change materials (PCMs) is an effective way of buffering thermal fluctuations and has the advantages of high-energy storage density and the isothermal nature of the storage process. The aim of this study is to develop novel heat management materials based on the enclosed PCMs for different applications of interest in mechanical engineering. In this study, solidification and melting processes of different types of PCMs employed in a multi-layer annulus with various thicknesses are numerically investigated. In order to solve the governing equations in which the natural convection heat transfer is also considered, a two-dimensional finite element (and also finite volume) method is applied. Different thermal boundary conditions are used to simulate the heat charging in different walls of the heat exchanger. Up to five layers in the same annulus are considered in order to put various PCMs with different possible arrangements and thicknesses. Simulation results are presented in the forms of liquid fraction, average temperature and their contours over the three periods of inner boundary oscillation. The computational results show that using more layers of different PCMs leads to fluctuation of liquid fraction and average temperature of layers with wider amplitude. For lower thicknesses of the outer layer, the system response to the employed boundary conditions will be rather in latent mode.
National Natural Science Foundation of China (NSFC) funding.