Enhanced analysis of flow characteristics and thermal performance in multiple jet impingements: Effects of varying jet heights and spacings

Background: Jet arrays are widely recognized as highly efficient cooling techniques. The focus of ongoing research has been on maximizing their heat transfer efficiency within confined spaces. Methods: Experimental studies and numerical simulations have been conducted to investigate the jet impingements at varying heights (H_c) and hole spacing (d_j) on circular jets within cooling channels. Single, two, and three jets are utilized, respectively, and jet holes possess a diameter (d) of 2 mm. The Reynolds number (Re) ranges from 72,673 to 145,346, and the dimensionless distance of the jet spacing (d_j/d) and the height to the target (H_c/d) varies between 3 and 5. Significant finding: Multiple jets generate significant turbulent and mixed flow patterns, with their heat transfer performance being influenced by various factors such as H_c, d_j, Re, and jet interactions. The heat transfer performance of two jets outperforms that of three jets, achieving its peak Nusselt number (Nu) value at Re =145,364, d_j/d = 3, and H_c/d = 5. A thorough discussion is conducted on the dimensionless parameter H_c/d_j. By appropriately adjusting H_c/d_j within a suitable range, it is possible to achieve more favorable flow dynamics, leading to enhanced cooling performance of the jet system.