A Numerical Investigation of Encapsulated Phase Change Materials Melting Process via Enthalpy-Porosity Approach

Today, with the increasing need for energy and the limitation of fossil fuels as depleting and polluting sources of the environment, the need to use more renewable energy sources is felt. The use of PCM materials in buildings, power generation, food industry, and automotive applications is presented. This paper presents the melting process time of a Phase Change Material (PCM) to investigate the impact of various Heat Transfer Fluids (HTFs), using the coupled enthalpy-porosity method and VOF approach. The PCM that is considered is a hydrated salt, Sodium Nitrate (NaNO۳) which is encapsulated in a stainless steel infinitely long cylindrical capsule and placed horizontally in a laminar cross flow arrangement with air and Therminol/VP-۱ as the HTFs. The Finite-volume-based method has been employed to solve the governing equations for the heat transfer inside and outside the encapsulated PCM. With this technique, the algebraic equations (discretization) are replaced by the governing equations. Then, a set of coupled nonlinear algebraic equations has been solved numerically. The results for the dynamic of the liquid/solid interface at different intervals during the PCM’s melting process exhibited that the heat transfer process inside the encapsulated PCM is influenced by HTF types, and PCM melting times are significantly impacted by the flow specifications of HTF on the surface of the capsule.

کلیدواژه ها:

Phase Change Materials ، Thermal Analysis ، Thermal transfer simulation ، Enthalpy-porosity method ، Front tracking method