LAUSR

Abstract Transient problem of freezing phenomena within a system including two wavy PCM layers has been analyzed in this research. Existence of three air cold flow duct among the PCM layers make it possible to observe solidification of paraffin. The selected PCM is RT30 and Al2O3 nano-powders were added to remove the limitation of paraffin. As paraffin solidifies, heat releases and makes air warmer. The worst state in view of time is a = 5 mm and φ = 0.04 which takes 19,193 s to achieve full solidification. The minimum required time for freezing occurs at a = 20 mm and φ = 0.04 which takes 11,479 s. At t = 150 s, augment of amplitude leads to 25.27% augmentation in solid fraction and 2.5% reduction in temperature. Also, at same time stage, adding nanoparticles makes temperature to reduce about 0.42% while solid fraction augments about 1.96%. With augment of amplitude, required time decreases about 36.71% and 35.82% when φ = 0 and 0.04, respectively. Freezing time declines about 5.49% with addition of nano-powders when a = 20 mm.