Keywords : jet impingement cooling
Engineering and Technology Journal,
2016, Volume 34, Issue 2, Pages 205-219
Experimental investigation of jets impacting at right angleon a flat surfaceis introduced in the present study. Round jet holes of inline arrays arrangements with diameter (5mm) and jet to jet spacing of 4 jet hole diameter are considered. Jet Reynolds numbers of 4000 to 16000 and jet height to diameter ratio (space between the jet plate and target plate) of 2.0 is maintained. The heat transfer model consists of amultiple jet holes, ribbed target plate having back side resistive film. Threetarget models have been considered; model (1) is a clean surface target acting as the baseline case, the model (2) the target surface consists of lateral rib rows and model (3) the target surface consists grids rib arrangement. The ribs height for models (2 and 3) is 0.86 of jet diameter of the triangle shape. The average wall cooling effectiveness and heat transfer coefficients and consequently the Nusselt numbers for each model are estimated. Numerical computations of jets flow field are made.Theresults show that model (3) enhanced both heat transfer coefficients in the target plat inner surface and wall cooling effectiveness in the target plat outer surface greatly,the maximum increments in heat transfer coefficient and wall coolingeffectiveness are 14.5% and 4.5% respectively.