الفهرس 
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Abstract
An experimental and computational studies were conducted to investigate the melting and solidification process of a phase change materials (PCMs) filled in a horizontal cylindrical capsule. Lauric acid, Paraffin wax, and RT60 (type of paraffin wax having melting temperature of 60 ⁰C) as PCMs were used in this study. In an experimental study Paraffin wax and Lauric acid were used as a PCMs. The capsulated PCMs were placed in an insulated rectangular galvanized steel test section except the front side of the test section made of acrylic (plexiglass) transparent material for melting interface visualization by a camera to follow the instantaneous melting process inside the capsule by dimensions (300 mm height, 250 mm width and 2 mm thick). In the experiments, two tests were conducted at inlet hot water temperatures of 55 ⁰C and 73 ⁰C for Lauric acid and Paraffin wax melting respectively. The hot water was supplied at a mass flow rate of 0.033 kg/sec around the capsule with dimensions 26 mm diameter, 2 mm wall thickness and 76 mm length, which the capsule made of pyrex-glass material. Image processing method was used to capture the melting interface, and the instantaneous liquid fraction. These two measured parameters were used to validate the proposed numerical model. On the other hand, a 2D numerical model was developed to extend the effect of different parameters on the melting and solidification phenomena of the capsulated PCM. A commercial CFD ANSYS-Fluent 2019 R2 was used through the simulation. The model was validated by comparing the results with the results from the present experiments and recent results from the literature. In the simulation work, the effect of charging and discharging processes, capsule diameters, PCM materials, mass water flow rate, inlet water temperatures, capsule material, and fins number inside PCM capsule were numerically studied. The instantaneous variation of the PCM liquid fraction rate, PCM temperature, PCM energy stored, capsule wall temperature, outlet water temperature, and the complete melting time were computationally estimated. Further, the results reveal that the total melting time and solidification were enhanced by about 46% from 55 ºC to 70 ºC for water mean inlet temperature for lauric acid lower than that for paraffin wax, the total melting time decrease by around 30% and 22% with increasing the hot mass water flow rate five times of initial value (0.033 kg/sec) for both lauric acid and paraffin wax respectively. The total energy stored in paraffin wax is much higher compared to the lauric acid at the same inlet water conditions. Increasing the number of fins from 0 to 12 fins enhance the melting time by 41 % for paraffin wax at mass water flow rate 0.3238 kg/sec, and inlet temperature 73 ºC. The presence of fins number is more effect in enhancement of solidification time than that melting time for lauric and paraffin wax. The effect of varying mass water flow rate ranges from 0.033 kg/sec to 0.3238 kg/sec on the melting process was more than that solidification process for PCMs, therefore from the results, the effect of different water mean inlet temperatures were the main factor for the charging process to improve the PCM melting and solidify time in this study.