ISSN Online: 2688-7231
ISBN Flash Drive: 978-1-56700-497-7
ISBN Online: 978-1-56700-496-0
Proceedings of the 25th National and 3rd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2019)
Modified Numerical Model for Solidification Shrinkage of Phase Change Materials with Large Difference in Phase Specific Heat and Density
摘要
Phase change material (PCM) can be used as the storage
material because of its high energy density. Most of the PCMs
used in the fields of thermal engineering have large phase
difference in thermophysical properties, i.e. density, specific heat, and thermal conductivity. During the melting and
solidification cycles of PCMs, the phase density difference
often causes undesirable shrinkage void formation and residual stresses. These shrinkage voids affect the heat transfer
performance of PCM based thermal energy storage systems.
Some metallic PCMs have large phase differences in density
and specific heats. In the present work, an energy equation is
developed by incorporating different specific heats and
densities for different phases. Continuity equation and energy
equation are derived from the first principle to obtain the
source terms. Numerical simulation is carried out using
octadecane as the PCM. Two case studies are considered. In
the first case, the densities are kept the same, while specific
heats of two phases are taken differently. In the second study,
both specific heats and densities are taken differently for
different phases. The numerical results are validated with
experimental results reported in the literature.