Energy-efficient thermal drying using impinging-jets with time-varying heat input – A computational study

This study investigates the performance of impinging-jet drying at various configurations. The computational fluid dynamic (CFD) approach was used for solving the conjugated heat/mass transfer problem during drying with impinging-jets. In short, the model considers slab material with drying chamber, and solve for conservation equations of mass, momentum, species and energy with associated turbulence model. To ensure the validity of the mathematical model, validation with the experimental data is carried out. The effect of jet velocity, pulsation and intermittency on the jet inlet, slab geometry and slab thickness are then investigated. The results are then examined to obtain optimum conditions for impinging-jet drying of model materials in the form of a thin slab. Finally, it is noted that lower energy consumption of impinging-jet with pulsating and/or intermittent flow offers comparable drying kinetics as compared to that with that of a steady jet, which shows potential for energy saving.

► We develop a conjugate model of drying using impinging-jet.
► The model is validated against experiment counterpart.
► Effects of jet velocity, substrate thickness, and substrate shape are investigated.
► Drying performance of steady, pulsating and intermittent jets are compared with regards to energy efficiency.