Experimental study on the heat transfer under impinging jet array for low jet-to-plate distances

In recent years energy efficiency and sustainability have become very important. In this aspect, it is important in many engineering applications to increase the heat transfer rate in order to reduce energy consumption and thereby increase the efficiency of the system. This is regarded as the first step for a more sustainable energy future. In this study, the effects of low jet-to-plate distance on the impinging jet heat transfer are experimentally investigated. Heat transfer results from these surfaces under impingement of a circular jet array (5x3) using an infrared thermal imaging technique are presented. The heat transfer data were collected at Reynolds numbers equal to 2000, 6000 and 10000. Along the target plate, different heat transfer results were obtained for low jet-to-plate distances (H/d=0.2, 0.4, 0.6, 0.8 and 1.0). Local and average Nusselt number distributions and also Nusselt number contours are presented. The lowest and highest heat transfer values are obtained for H/d=0.2 and H/d=1.0, respectively. As expected, heat transfer enhances with increasing Reynolds number. For lower H/d it was observed that wall jet interaction enhances and due to this heat transfer decreases.