Spray cooling as an effective cooling technique is widely used in practice. Compared to small heating surfaces, the significantly increase of surface would pose a great challenge to the significant enhancement of spray cooling. Specially, single nozzle spray cooling suffers from non-uniform liquid thin film on a relatively large heating surface, severely inhibiting the formation of efficient thin film evaporation. In this study, two enhanced surfaces such as straight fin surface and cubic fin surface with a relatively large heating surface of 4 cm were designed for single nozzle spray cooling. A parametric study was conducted with aims to evaluate the effects of flow rate, spray distance and enhanced surfaces on the formation of thin liquid film and then the performance of spray cooling. Visualization was presented to observe the development of liquid film to elucidate the enhanced mechanism of spray cooling. In this work, spraying height is varying from 20 to 40 mm. Coolant flow rate is ranging from 70 to 100 ml/min. The experimental results show the distribution of liquid film plays an important role in spray cooling, especiallyin the single-phase regime. In two-phase regime, nucleate boiling is significantly boosted on the engineered surfaced. For instance, the cubic fin surface leads to an enhancement of HTC of nearly 24 % compared to that of flat surface.

中文翻译：

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增强型较大表面喷水冷却的参数研究

喷雾冷却作为一种有效的冷却技术在实际中得到广泛应用。与较小的受热面相比，受热面的大幅增加对喷雾冷却的显着增强提出了巨大的挑战。特别是，单喷嘴喷雾冷却在较大的受热面上存在液体薄膜不均匀的问题，严重抑制了高效薄膜蒸发的形成。在本研究中，设计了两种增强表面，例如直翅片表面和立方翅片表面，其受热面相对较大，为4 cm，用于单喷嘴喷雾冷却。进行了参数研究，旨在评估流量、喷雾距离和增强表面对薄液膜形成以及喷雾冷却性能的影响。提出可视化来观察液膜的发展，以阐明喷雾冷却的增强机制。在这项工作中，喷涂高度从 20 到 40 毫米不等。冷却液流量范围为 70 至 100 毫升/分钟。实验结果表明，液膜分布在喷雾冷却中起着重要作用，特别是在单相状态下。在两相状态下，工程表面上的核态沸腾显着增强。例如，与平面相比，立方体翅片表面的 HTC 提高了近 24%。