Heat transfer characteristics of the jet deflector impinged by underexpanded jets

An experimental investigation is carried out to study the local convective heat transfer between smooth wedge shaped plate and a single round underexpanded impinging jet, using thin metal foil technique and IR camera. In the present study experiments are carried out for five different nozzle pressure ratios in the range of 2.36-5.08. The jet-to-wedge apex distance (z/d) is varied from 1 to 12 nozzle diameters. The influence of the included angle of wedge is studied by carrying out experiments for three apex angles of 31.5°, 63° and 94.5°. Heat transfer coefficient is calculated based on wall temperature. The local Nusselt numbers, stagnation point Nusselt numbers and recovery factor distribution are reported in present study. Shadowgraphs are used to explain distribution of Nusselt number and recovery factor. It is concluded that local Nusselt number and recovery factor are greatly affected by the nozzle pressure ratios but independent of wedge apex angle.