Impact of lifters on velocity and residence time distributions of fabrics in a tumble dryer

Abstract

The impact of lifters on fabric motion in tumble dryers was examined in this study. A trajectory tracking system based on visual imaging techniques was used to investigate the transverse motion of tracer fabric. From the observation of velocity and residence time distributions of tracer fabric, fabric transverse motion can be divided into passive and active regions. These are entirely consistent with existing forms of bed motion describing the behavior of granular media in rotating cylinders in other fields such as chemical engineering, food drying, and clothes washing processes. Experimental and theoretical analyses indicated that the number of lifters had appreciable impacts on the dynamics of fabric motion, manifested in differences in motion pattern and lift height, thereby enhancing the heat and mass transfer inside the drying drum. This can be seen by comparing drying performance under different drying conditions. The findings in this study shed more light on the impact of lifters on fabric transverse motions which has significant implications for the overall design of tumble dryers.