Kinetics of contact ultrasonic drying of thick woolen fabric

Abstract

The article is devoted to an experimental research of the effectiveness of continuous contact ultrasonic drying of dense woolen fabrics. For drying, an experimental stand was created in the form of a small-sized continuous-action drying machine. In the process, the dried fabric is rewound from reel to reel, through the zone of ultrasonic (150 W) and thermal (at temperatures of 50 °C and 80 °C) exposure. It has been established that ultrasonic action (together with thermal) provides a reduction in drying time from 18% to 28%. Moreover, at a lower temperature, the contribution of ultrasonic vibrations to the reduction of drying time is higher. The drying schedules were approximated by a formula expressing the dependence of the moisture content of the material on temperature and the presence of ultrasonic exposure. The resulting approximation formula can be used to analyze the curves of convective drying of dense woolen fabrics, taking into account the temperature of the drying agent and the presence of ultrasonic exposure, including predicting the duration of such types of drying.