Heat Transfer From an Isothermally Heated Flat Surface Due to Confined Laminar Twin Oblique Slot-Jet Impingement

Abstract

Convective heat transfer from a heated flat surface due to twin oblique laminar slot-jet impingement is investigated numerically. The flow domain is confined by an adiabatic surface parallel to the heated impingement surface. The twin slot jets are located on the confining surface. The flow and geometric parameters are the jet exit Reynolds number, distance between the two jets, distance between the jet exit and the impingement surface, and the inclination angle of the jet to the impingement surface. Numerical computations are done for various combinations of these parameters, and the results are presented in terms of the streamlines and isotherms in the flow domain, the distribution of the local Nusselt number along the heated surface, and the average Nusselt number at the heated surface. It is found that the peak and the average Nusselt number on the hot surface mildly decreases and the location of the stagnation point and the peak Nusselt number gradually moves downstream as the impingement angle is decreased from 90 deg. The heat transfer distribution from the impingement surface gets more uniform as the impingement angle is reduced to 45 deg and 30 deg at lager jet-to-plate distance (4–8) with a corresponding overall heat transfer reduction of about 40% compared to the normal impinging jet case. The specified jet exit velocity profile boundary condition has considerable effect on the predicted Nusselt number around the impingement location. Fully developed jet exit velocity profile correctly predicts the Nusselt number when compared to the experimental data.