Predictive Modeling Of Solidification Characteristics Of A Phase Change Material In A Metallic Spherical Capsule Fitted With Fins Of Different Lengths

This study investigates the effect of fin length on solidification characteristics of deionized water filled in a stainless steel spherical capsule immersed in a constant temperature bath. Alongside, Box-Benkehn experimental design is employed to develop mathematical models for predicting solidification duration using response surface regression. Experiments are carried out at three different bath temperatures (-6 degrees C - 9 degrees C and -12 degrees C). Four radial fins of 3 mm diameter made of copper are fixed on the inner surface of the spherical capsule. Three fin-lengths of 7.5 mm, 13.5 mm, and 19.5 mm are chosen which corresponds to the annulus volume margins of 50%, 75%, and 90% respectively measured from the inner surface of the capsule. Results revealed that the fin length has no significant effect on the duration of solidification. The individual as well as interactive effects of frozen mass fraction and bath temperature were found to be statistically significant. The models developed were found to be statistically significant at a 99% confidence level and the confirmatory experiments validated that the developed models were able to predict the solidification time with reasonable accuracy. It was found that there is an improvement in solidification duration in the range between 17% and 21% using the combinations predicted by the desirability approach when compared to a capsule fitted with no fin under similar conditions. The spherical capsule fitted with a fin of length 16.5 mm shows a reduction of 21% in solidification duration to achieve 96% of frozen mass at a bath temperature of -12 degrees C.