Measurement and prediction of void fraction and pressure drop during air drying process of wet particle packed bed

This study aimed at development of a pressure drop prediction method at a drying process by flowing air through a wet particle packed bed saturated with distilled water. At first, the pressure drop measurement during the drying process of the wet particle packed bead of glass sphere was carried out, and a method for predicting the pressure difference of the bed was proposed by investigating the effect of liquid saturation on the bed void fraction. It was clarified that the effect could be predicted by a simple model by considering liquid bridges formed between particles. Next, the liquid saturation when the measured pressure difference suddenly decreased was investigated as the residual saturation. The value was like that of past research. Finally, considering the effect of liquid saturation on the bed void fraction and the influence of the residual saturation on the relative permeability of liquid phase, more than 90 % of all pressure drop data could be predicted with an error of less than +/- 15 %. Furthermore, in the range where the gas-phase velocity was large, it was important to predict the pressure difference considering the change of the bed void fraction and the residual saturation.