Mohammad Yaseen Shaker Alawadi

In this work, a comprehensive investigation is conducted to investigate the melting and solidification processes of PCM encapsulated in a circular capsule with and without internal fins. Based on the predicted results, the lauric acid melting time decreases with an increase in the mean inlet water temperature. The decrease in the total melting time is ~ 46% from 55 ◦C to 70 ◦C mean inlet water temperature at a mass water flow rate of 0.3238 kg/s. The paraffin wax melting time is much higher compared with that of lauric acid under the same condition. Further, the melting time of lauric acid decreases by 37% by increasing the number of fins inside the capsule from 0 to 12 at a mass water flow rate of 0.3238 kg/s and inlet temperature of 70 ◦C. Furthermore, increasing the number of fins from 0 to 12 enhances the melting time of paraffin wax by 41% at a mass water flow rate of 0.3238 kg/s and inlet temperature of 70 ◦C. Based on the obtained results of the finned capsule, increasing the number of fins beyond four inside the capsule slightly enhances the melting and solidification characteristics. finding could be an important point for the practical implementation of finned capsulated PCM. As upcoming step, the effect of fin thickness, and length could be further investigated to find the optimal dimensions of the fins incorporated into the PCM capsule at the same amount of PCM

A numerical and an experimental study of transient laminar flow past cylindrical PCM capsule is presented. The numerical finite-volume method is utilized twodimensional CFD simulations to study the thermal characteristics of an energy storage system. The effect of the different water mean inlet temperature, different water inlet mean velocity, different capsule material and different PCM is presented. For all examined cases, the following conclusions are made: 1- The lauric acid melting time decreases with the increase of the inlet mean water temperature. The enhancement in the total time melting is 43% for 4.6% increase in water mean inlet temperature. 2- Increasing the inlet water velocity (Reynolds number) decreases the melting time of the lauric acid. The enhancement in the total melting time is 18% for 500% increase in inlet water mean velocity. 3- The melting time decreases with the increase of capsule thermal conductivity. The improvement in the total time melting is 7% when used copper capsule wall. 4- The energy stored of the paraffin wax is higher than that lauric acid for the same working fluid, and capsule size with same material wall, but when compared to the total melting time of paraffin wax to lauric acid, which is approximately three times the melting time of lauric acid, the amount of latent heat stored to the lauric acid pyrex-glass capsule is 47% higher than paraffin wax capsule if the lauric acid is melted at the same time as paraffin wax.

1. The temperature of convective air flow and copper foams in the axial direction decreases (slightly) at all temperatures in clean and dusty air for (10PPI & 40PPI). 2. The pressure of the copper foam filter with 40PPI is higher than the copper foam filter with 10PPI at all values of Reynolds Number and all temperatures, the pressure increases with increasing dust concentration (C) or dust density (N= 2, 4, 6 & 8). 3. The pressure through copper foam filter with 40PPI is higher than the 10PPI, and the pressure for dusty air at dust density (N= 2 & 4) is higher than the clean air at same conditions. 4. The pressure drop for the copper foam filter with 40PPI is higher than the copper foam filter with 10PPI. 5. In the present work, the numerical pressure drop in copper foam filter is higher than that obtained experimentally for clean and dusty air. 6. The permeability increases almost linearly with increasing the pore diameter at fixed porosity. Comparison gave a good agreement between the present and previous works