Numerical simulation of three-dimensional transient cooling application on a portable electronic device using phase change material

摘要

A numerical transient three-dimensional heat transfer investigation of a hybrid PCM based heat sink cooling technique was presented in this study. Thermal energy was transferred to the calculation domain through the base of heat sink. The n-eicosane was adopted inside the heat sink cavity as the Phase Change Material (PCM) for latent heat storage. The governing equations were solved numerically by a control-volume-based finite-difference method using a power law discretization scheme to describe the heat transfer in the simulated system. The melting mushy zone, around the phase change boundary, was predicted by an enthalpy-porosity approach. In addition, the PCM-air VOF (Volume of Fluid) model was adapted to solve PCM-air gap boundary which was caused by PCM's volume expansion for the difference of variable density. In this study, numerical computations have been conducted for various power levels (2 W-4 W), different orientations (vertical/horizontal/slanted), and charge and discharge modes. Different time steps (0.03/0.05/0.07 s) were discussed in the literature for transient accuracy as well. The developed theoretical model was validated by comparing numerical predictions with the available experimental data by Fok et al. [9]. The numerical results showed that the temperatures were reasonably predicted with a maximum discrepancy within 10.2%.