Investigation of transient operation on tumble dryers

In this project, the start transient, steady-state operation and shutdown transient of a tumble dryer are experimentally investigated and a transient simulation model is developed using FORTRAN program. Both air-vented and air-condenser tumble dryers are employed in the present experiments. Relative humidity and temperature are measured at the drum outlet, also at the upstream of the heater that is located near the inlet of the drum. Using these measurements, the total mass transfer coefficient is calculated during the drying process. Several factors, which influence the characteristics of the total mass transfer coefficient, are investigated by the design of experiment method. The results show that the total mass transfer coefficient mainly depends on the amount of water remaining at the surface of the clothes. The experimental results have aided to the modeling of the tumble dryer operation. The main components of a tumble dryer such as fan, condenser, drum and heater are modeled, and the entire drying process from the start to the shutdown period is simulated. The simulation results are found to be in good agreement with the experimental data. The simulation model may be employed in the process of a new tumble dryer design.