Through air drying of tissue and towel - fabric drying and heating

In studying the through air drying of tissue and towel, the drying and heating of TAD fabrics as part of the overall system has been considered for the first time. For a simple, single layered structure of the TAD fabrics, the convective drying and heating has been modeled using well-known heat and mass transfer models developed in general chemical engineering practice. The models considered are circular pipe flow, flow over cylinder and packed bed. All three models predict a long fabric drying period and a quick fabric heating period. The constant temperature of the fabric during the fabric drying period predicted by all three models are almost the same. This constant temperature is close to the adiabatic saturation temperature of the inlet air, dependent only on the temperature and supply humidity and not the air flow rate. The drying rates predicted by the packed bed model and flow over cylinder model are significantly higher than that by the circular pipe flow model. Further verification on the suitability of using either the packed bed or the flow over cylinder model to simulate fabric drying and hearing during through air drying is suggested.