A numerical investigation of melting process for encapsulated PCM via enthalpy-porosity approach: Application to Sodium Nitrate

In the present study, the melting process time of a phase change material (PCM) is conducted to investigate the influence of various heat transfer fluids (HTFs), using the coupled enthalpy-porosity method and VOF approach. The PCM considered is a hydrated salt, Sodium Nitrate (NaNO۳) which is encapsulated in stainless steel infinitely long cylindrical shaped capsule and placed horizontally in a laminar cross-flow arrangement with air and Therminol/VP-۱ as the heat transfer fluids. The direction of the flow is from the top of the capsule to the bottom and phase change simulation assumptions are as follows: incompressible molten PCM and HTF flow, constant properties of solid and melted PCM, gravity effects, and natural convection are neglected. The results for dynamic of the solid/liquid interface at various times during the melting process predicted by the enthalpy-porosity illustrated that the heat transfer process inside the encapsulated PCM is impacted by the types of HTFs and melting times of the PCM are strongly influenced by the flow characteristics of HTF on the surface of the capsule. The results also showed that the proposed enthalpy-based formulation is capable of predicting solid/liquid interfaces and trustworthy tool in the study of transient phenomena in phase change systems.

کلیدواژه ها:

PCM ، Thermal Analysis ، Thermal transfer simulation ، Enthalpy-porosity method ، Front tracking method