Experimental Study of the Dynamics of Water Film on an Aluminum Substrate under Wind Shear

Abstract

Aircraft icing poses a serious threat to flight safety. Unfrozen parts of impinging water on the surface of the aircraft will run back under the effect of high-speed airflow, altering liquid distribution and heat transfer characteristics. In this paper we conducted a series of experiments over a wide range of wind speed (Ua = 17.8~52.2 m/s), film Reynolds number (Ref = 26~128) and inclined angle (α = 0°, ±30°, ±45°) to investigate the dynamics of thin water film on an Aluminum substrate. The superficial morphology of the water film were investigated by high-speed camera, and the instantaneous film thicknesses were measured by a laser focus displacement meter based on a confocal chromatic technique. The interface between the gas and liquid phases consisted of underlying thin film and multiple scaled fluctuations. The measured time-averaged filim thickness data agrees with previous model predictions. Based on the experimental results, a relationship between the film thickness and the wind speed, film Reynolds number, inclined angle was proposed. A new correlation to calculate the interfacial shear stress and superficial roughness on the wavy surface is also suggested.