Abstract Spray impingement is widely applied in many fields, and the liquid film formed on the impact surface is closely related to the heat and mass transfer. In present paper, an experimental setup of the spray impingement with an air-atomizing nozzle was established to study the water film formed on a flat surface. And the planar laser-induced fluorescence technology was applied to measure the film thickness at different spray heights (10–40 mm) and water flow rates (60–120 ml/min). Based on the film topography, the water film was divided into the impact zone and the free flow zone. The film thickness in the impact zone was thinner than that in the free flow zone. The water film at the center of the impact surface intensely fluctuated, and the steady layer thickness was 0.33–0.73 mm. The film thickness in the free flow zone presented a camelback topography of first increasing and then decreasing with the increase of the radial distance. Besides, the film thickness in the free flow zone decreased with increasing the spray heights and increased with increasing the water flow rates. The maximum film thickness was 2.27 mm and the average film thickness in the free flow zone was 0.85–1.50 mm. The study provides much more experimental data with the study on the liquid film thickness under spray impingement.

中文翻译：

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基于平面LIF的喷雾冲击下水膜厚度实验研究

摘要 喷射冲击在许多领域都有广泛的应用，冲击表面形成的液膜与传热传质密切相关。在本文中，建立了带有空气雾化喷嘴的喷雾冲击的实验装置，以研究在平坦表面上形成的水膜。并应用平面激光诱导荧光技术测量不同喷雾高度（10-40 mm）和水流量（60-120 ml / min）下的膜厚度。根据膜的形貌，将水膜分为冲击区和自由流动区。冲击区的膜厚比自由流动区的膜厚薄。撞击面中心的水膜波动剧烈，稳定层厚度为0.33-0.73 mm。自由流动区的膜厚呈现出随着径向距离的增加先增加后减小的驼峰形。此外，自由流动区的膜厚随着喷雾高度的增加而减小，随着水流量的增加而增加。最大膜厚为 2.27 毫米，自由流动区的平均膜厚为 0.85-1.50 毫米。该研究为喷雾冲击下液膜厚度的研究提供了更多的实验数据。27 毫米，自由流动区的平均膜厚为 0.85-1.50 毫米。该研究为喷雾冲击下液膜厚度的研究提供了更多的实验数据。27 毫米，自由流动区的平均膜厚为 0.85-1.50 毫米。该研究为喷雾冲击下液膜厚度的研究提供了更多的实验数据。