The aim of this study is to mitigate the distorting effect of crossflow on jet flow and to enhance heat transfer performance in multi-jet impingement heat transfer. To accomplish this objective, novel jet extension designs are proposed: a design with uniform jet extension, a design with linear jet extension in the streamwise direction, a design featuring an initial increase followed by a decrease, a design featuring an initial decrease followed by an increase, and a design where the last five jets exhibit a uniform extension inside the region mostly influenced by crossflow. The effects of various novel jet extension designs on flow and heat transfer are analyzed numerically in this study, focusing on the following: velocity contours, streamlines and velocity vectors, Local Nusselt number variations, variations of the average Nusselt number, friction coefficient, and thermal enhancement factor with Reynolds number. The study findings indicate that the investigated nozzle extension designs yield a notable enhancement of 13.26% in heat transfer. However, it is important to note that these designs may also lead to a substantial rise of 39% in the friction coefficient. In relation to thermohydraulic performance, it is found that all extension designs exhibit better results when compared to the reference state. Notably, the uniform extension design with dimensionless nozzle length of 2 demonstrates a higher degree of thermohydraulic performance.

中文翻译：

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在多射流冲击中利用新颖的射流延伸设计来减轻横流和提高热效率

本研究的目的是减轻横流对射流的扭曲效应，并提高多射流冲击传热中的传热性能。为了实现这一目标，提出了新颖的射流延伸设计：射流延伸均匀的设计、沿流向线性射流延伸的设计、先增大后减小的设计、先减小后减小的设计。增加，以及最后五个射流在主要受横流影响的区域内呈现均匀延伸的设计。本研究对各种新颖的射流延伸设计对流动和传热的影响进行了数值分析，重点关注以下内容：速度轮廓、流线和速度矢量、局部努塞尔数变化、平均努塞尔数变化、摩擦系数和热传递。雷诺数的增强因子。研究结果表明，所研究的喷嘴延伸设计使传热显着提高了 13.26%。但需要注意的是，这些设计也可能导致摩擦系数大幅上升39%。关于热水力性能，发现与参考状态相比，所有延伸设计都表现出更好的结果。值得注意的是，无量纲喷嘴长度为 2 的均匀延伸设计表现出更高程度的热工水力性能。