A NUMERICAL STUDY OF THE FLOW AND HEAT-TRANSFER CHARACTERISTICS OF AN IMPINGING LAMINAR SLOT-JET INCLUDING CROSS-FLOW EFFECTS

A numerical model, based on the finite-volume procedure, is constructed and applied for calculating the steady flow and heat-transfer characteristics of a laminar slot-jet impinging on an isothermal flat surface. Three cases are studied; namely, free-jet impingement, semi-confined-jet impingement and semi-confined-jet impingement through a crossflow. The model is validated by comparing results with available experimental data for the case of a free-jet impingement; the agreement is found to be very good. A parametric investigation is carried out by varying the following parameters: the jet Reynolds number, the fluid Prandtl number, the length of the heat-transfer surface, the jet-exit to impingement-surface distance and, in the case of a crossflow, the crossflow-to-jet mass-flow-rate ratio. The average Nusselt number is correlated for the range of parameters studied and show that the crossflow can degrade the nominal heat-transfer rate by as much as 60%.