Abstract Jet impingement cooling is an effective means of inducing high convective heat transfer coefficients for applications such as the cooling of gas turbine surfaces, drying of textiles, and the tempering of metal and glass. Slot jets can be used for applications which require cooling over a line or strip, and these can be realized at the micro-scale if size is constrained. In this paper the application of these jets is of specific interest for high-density photonic integrated circuits (PICs), which can generate device-level heat fluxes as high as 1 kW / cm 2 . In this context, an understanding of the thermal and hydrodynamic behaviour of low Reynolds number, submerged, confined and normally impinging slot jets is currently unavailable in the literature and would be beneficial for the design of micro-scale cooling systems. This investigation utilized the isoflux heated foil technique and Particle-Image Velocimetry (PIV), to measure the single-phase convective heat transfer and velocity fields associated with confined liquid slot jets. The aspect ratios of the jets were varied from 1 to 8, with a constant hydraulic diameter, in order to determine the influence of aspect ratio on the measured parameters. The study was carried out over a jet exit Reynolds number range of 100–500, and a fixed confinement ratio of H / D h = 1 . The results showed that, enhancements of up to 68% in area-averaged heat transfer could be achieved through increasing slot jet aspect ratio, with a corresponding 12% reduction in head loss coefficient. The appearance of off-center peaks in the velocity and Nusselt number distributions were also observed. These peaks were concluded to be as a result of the stagnation zone fluid dynamics and local flow entrainment.

中文翻译：

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受限的、正常撞击的层流槽射流的热和流体动力学行为

摘要 射流冲击冷却是在燃气轮机表面冷却、纺织品干燥以及金属和玻璃回火等应用中产生高对流换热系数的有效手段。狭缝喷射可用于需要对生产线或带材进行冷却的应用，如果尺寸受到限制，则可以在微尺度上实现。在本文中，这些射流的应用特别适用于高密度光子集成电路 (PIC)，它可以产生高达 1 kW / cm 2 的设备级热通量。在这种情况下，对低雷诺数、浸没、受限和正常撞击狭缝射流的热和流体动力学行为的理解目前在文献中是不可用的，这将有利于微型冷却系统的设计。本研究利用等通量加热箔技术和粒子图像测速 (PIV) 来测量与受限液体狭缝射流相关的单相对流热传递和速度场。射流的纵横比在 1 到 8 之间变化，具有恒定的水力直径，以确定纵横比对测量参数的影响。该研究是在射流出口雷诺数范围为 100-500 和固定限制比 H / D h = 1 上进行的。结果表明，通过增加狭缝射流纵横比，可以实现高达 68% 的面积平均传热增强，同时水头损失系数相应降低 12%。还观察到速度和努塞尔数分布中出现偏心峰。