Infrared Assisted Convective Drying of Moist Paper Handsheet: A Numerical Study

The motivation of this study is to understand the combined effects of electrical infrared (IR) emitters, dielectrophoretic (DEP) mechanism, and hot air drying with slot jet reattachment (SJR) nozzles altogether on drying of moist paper handsheets. Experiments and simulations are conducted to physically understand heat transfer characteristics on a uniquely designed, fully electrified smart dryer without gas burners, aiming to reduce carbon footprint. In this work, a simulation for the smart dryer that allows infrared-assisted convection drying is developed. The finite difference method is implemented in the drying process simulation of combined technologies under different operating conditions, including dryer temperatures, air flow rate, and IR surface temperature, to provide physical insight numerically. Experiments are carried out on paper handsheets to verify IR energy penetration and combine its effect into the governing equation, not just as a boundary condition but also as an internal heat source by an absorption coefficient for paper pulp. Varying view factors on infrared drying are also assessed for continuous drying. The experiment-fused simulation gives us an in-depth understanding of infrared-assisted convection drying, showing the effectiveness of combining SJR and DEP drying and enabling future optimization to reduce energy costs without losing quality.