Numerical analysis of effective parameters on melting process in an enclosure with step by step and filled with phase change materials

Energy storage has gained great importance in recent years. Because energy storage is the most important parameter that affects the energy efficiency, energy continuity and energy security for the storage of heat and electricity. Since our country has a high level of foreign dependency in the field of energy, it is important to store the energy obtained. For systems with different temperature boundary conditions in closed spaces, energy storage by using Phase Change Material (PCM) is seen in many engineering applications such as cooling systems, heating systems, heat exchangers, solar energy systems. The melting and solidification rate control of PCM is a parameter worth examining in terms of energy efficiency. In this thesis, the melting problem in a closed volume filled with PCM, which is an important flow model in the field of engineering, will be examined theoretically. A research was conducted on numerical examination of sharp-edged geometries that are frequently encountered in engineering applications and affecting the flow, and to determine the energy losses due to flow separation. The study was modeled in the Computational Fluid Dynamics (CFD) package program and the results were examined. The main goal of the study is to analyze the effects of the new geometry on the melting rate by streamlined sharp corners. This study was carried out over different temperature boundary conditions for three different dimensions of two different geometries. The L/H ratios used in the physical model are in the range of 0.5 ≤ L/H ≤ 2 and the temperature difference values are in the range of 40 °C ≤ ∆T ≤ 60 °C. The paraffin was used as PCM and this paraffin melts in a closed volume with a gradually changing wall. The lower and upper walls of the stepped step flow are considered insulated and the studies were carried out depending on the time. The obtained results reveal that the streamlined physical model can provide some advantages over the sharp-edged model in terms of heat energy storage with PCM and control of the melting rate without requiring additional energy. This study is especially important in terms of melting and solidification vessel design.