Multiple thermal and moisture removals from the moving plate opposite to the impinging slot jet

• Impingement jet flows toward a moving plate.
• Heat and moisture transport by the forced and thermal buoyancy convections.
• Regimes of forced convection dominated and buoyancy convection dominated.
• Multiple steady solutions through varying impingement jet flow speed.
• Multiple steady solutions through varying plate moving speed.

This study presents the numerical model of convective heat and moisture transfer of an impinging jet with a moving plate, taking thermal buoyancy effects into account by the formulation of Boussinesq approximation. Effects of thermal buoyancy strength (Gr), separation between slot and plate (H), impingement jet flow speed (Vjet), and the plate moving speed (Um) on the heat and moisture transport have been investigated. Contours of stream-function, heat-function and moisture-function, skin friction coefficient, and heat and moisture transfer rates are presented and analyzed for different flow situations. Multiple steady flow solutions are observed through continuously changing the impingement jet flow speed or varying the moving speed of the plate. In the regime of forced convection dominated flow, natural solution obtained from the rest state is coinciding with upward solution as Um < 1. In the heat transfer driven flow dominated regime, two flow solution branches are observed within the range of 0.4 ≤ Vjet ≤ 1.6, whereas three solution branches are obtained and the upward solutions are sustained only at the range of Um ≤ 0.7. The present researches will benefit the optimization design and operation control of cooling and drying systems with moving belts.