Experimental analysis of local and average heat transfer between circular impinging jet and flat plate

ABSTRACT Heat transfer over a heated plate positioned normal to the horizontal circular impinging jet is investigated experimentally. The area average and local heat transfer characteristics over a large plate impinged by jet of air are investigated for Reynolds numbers ranging from 10,000 to 45,000, with jet-to-plate distances of 3–20 d for a maximum range of 0 ≤ r/d ≤ 44. The experiment is carried out for two jet diameters of 5.88 mm and 11.5 mm on a plate of 600 × 300 mm2 impinged by a jet. The infrared (IR) thermal imaging method is used to find the temperature distribution over the heated plate. The combined heat transfer investigation of both local and area average gives a proper insight of the cooling phenomenon of the jet at any location over the plate. The investigation is effective in identifying areas with a greater rate of heat transfer. At various locations, the Nusselt number growth with increasing mass flow rate is studied. The area average heat transfer is discovered to be the highest at z/d = 3 for all Reynolds numbers in the A1 (0 < r/d < 2.17) region. However, for z/d = 6 and r/d = 0, the local Nusselt number is reported to be the highest. Reduction in area average heat transfer is reported in area A3, i.e., r/d = 6.5, and beyond this area, the profile of Nusselt number practically converges.