Numerical investigation of melt solidification behaviour in resistors heated by a macro-encapsulated one side

Phase change heat transfer is finding its place in an increasing trend in engineering applications. Solar energy systems are one of these applications. The intermittent daylight during the time of the day necessitates the development of alternative methods, especially for the storage of thermal energy. In this study, the effect of different macro FDM encapsulated geometries on forced convection heat transfer and heat storage performance in the channel is investigated. Within the scope of the study, channel angle, fluid inlet temperature, Reynolds number, surface heat flux and macro FDM encapsulated resistors are analysed numerically. The length ratio of the heat storage resistors was determined as the aspect ratio and designed as T-shaped (AR=0.34) and rectangular (AR=1) depending on the aspect ratio. The investigation was carried out in turbulent flow regime in the range of Reynolds number between 4,000 and 15,000. In addition, the air inlet temperature was varied between 12°C and 20°C and the surface heat flux was varied between 500 W/m² and 1200 W/m². The resistance angle was considered to be 30°, 60° and 90°. Calcium chloride hexahydrate (CaCl₂6H₂O) was used as heat storage material. The numerical modelling was verified according to the data obtained from experimental studies. According to the numerical modelling results, it was found that the duct heat transfer is directly proportional to the surface heat flux, duct angle, Reynolds number and air inlet temperature, and inversely proportional to the macro FDM encapsulated resistance aspect ratio. It is evaluated that the findings obtained will make a significant contribution to the literature in terms of quality and originality. According to the data obtained, the increase in channel heat transfer results in a decrease in the amount of stored heat. In addition, the increase in the resistance surface area significantly affects the melting-solidification rate, especially accelerates the solidification.