Numerical investigation on the heat transfer performance of the liquid metal array jet impingement

Liquid metal jet impingement can meet the cooling demands of heat fluxes exceeding 1 MW/m2. However, there is currently a lack of detailed research on the flow and heat transfer characteristics of it. To address this research gap, this paper numerically investigates the heat transfer performance of the array jet impingement utilizing liquid metal as coolant, focusing on its parametric effects to achieve an optimal design. Specifically, the threedimensional numerical models were designed to investigate the geometrical effects including cross-flow condition, jet diameter (D), the jet-to-plate distance (H), and the jet-to-jet spacing (S), as well as the Reynolds number (1500 <= Re <= 15000) on the heat transfer performance. The overall and the local heat transfer performance are evaluated by average Nusselt number (Nuave), the standard deviation of the temperature (TDev), the areaweighted temperature uniformity index (gamma T), respectively. The energy input is evaluated by the friction factor (f), and performance evaluation criterion (PEC). First, the comparison of the performance of the single-orifice jets and array jets show that, at the same flow rate, Nuave for array jets is 6.64 % higher than that for single-orifice jets, while f decreases by 67.90 %. Further, focusing on array jets, the cross-flow after impingement will reduce the impingement efficiency and negatively impact heat transfer performance. The Nuave decreases as the jet diameter increases, whereas f exhibits an opposite trend. The small jet-to-target distance and the dense jet array will result in strong crossflow. Conversely, an excessive jet-to-target distance weakens the impingement effect. Additionally, a sparsely arranged jet array reduces the number of jets. None of these conditions are conducive to effective heat transfer. Among all configurations, the array jet impingement with D = 1 mm, H/D =1, and S/D = 3 under minimal cross-flow conditions exhibits the best overall performance. Future research can focus on experiments involving liquid metal jet impingement and performance prediction under higher heat flux densities.