Numerical investigation of heat transfer performance of extended jet impingement cooling on the wavy target surface

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This study numerically examines the effects of an extended jet impingement cooling model with a wavy target surface on heat transfer. Jet impingement cooling is considered a crucial technique that extends the lifespan of components operating at high temperatures. This method enhances heat transfer by impinging jets on the surface to achieve a homogeneous temperature distribution. However, due to the deflection of downstream jets caused by crossflow, it is often not as efficient as required. The study is based on a series of numerical simulations comparing flat and wavy target surfaces to reduce the negative effects of crossflow. It investigates the effects of factors such as jet nozzle length and wave height of the target surface on heat transfer under different Reynolds numbers (Re = 15000, 25000, and 35000). The dimensionless parameters used in the study are the orifice surface-to-target surface distance (s/D = 0.5, 1.0, 2.0, and 3.0) and the wave depth-to-jet diameter ratio (H/D = 0.4, 0.6, 0.8, and 1.0). The simulation results indicate that extended jets and wavy target surfaces increase the Nusselt number (Nu) and improve heat transfer efficiency. Particularly at low Re numbers, reducing the s/D ratio and increasing the H/D ratio significantly enhance heat transfer. For instance, at Re = 15000, there is a 33.76% difference in average Nu numbers between s/D = 0.5 and a non-extended jet arrangement (s/D = 3.0) for H/D = 1.0. The results also evaluate how extended jets increase pressure drop on the jet target surface and its impact on the performance evaluation criterion (PEC). It is concluded that combining extended jets and wavy target surfaces could be an effective design for jet impingement systems, especially at low Re numbers (Re = 15000).