An Experimental Study of Wind-Driven Runback of Water Droplets over a Slippery Liquid Infused Porous Surface 2019-01-1951
The promising anti-icing performance of the slippery liquid infused porous surface (SLIPS) has been recently demonstrated for various engineering applications. The runback icing for aircraft and wind turbines could be effectively mitigated considering the timely removal of water droplets by the wind shearing force due to the low adhesion on the SLIPS. In this study, the flow fields both inside and around the wind-driven water droplets moving over SLIPS were experimentally investigated by using a Particle Image Velocimetry (PIV) technique. Previous studies majorly focus on the internal flow pattern before droplet incipient motion. The flow fields inside moving droplets were firstly investigated. As a result of the low surface adhesion of the SLIPS, droplet oscillations are eliminated, and the droplet internal flow field is corrected from the optical distortions. Besides examining the effects of the wind speed, the viscosity of the droplet was also studied by varying the water concentration of the glycerin-water solution. It was found that, the internal circulation was highly related with the droplet viscosity. The inner circulations within the droplets would be reduced, or eliminated, when the droplet viscosity was increased, which would change the droplet motion from sliding into rolling. It was suggested that the internal flow should be considered when theoretically modeling the wind-driven droplet movement over the SLIPS. The findings derived from this study would be very helpful for a broader anti-/de-icing applications of SLIPS.
Liqun Ma, Hui Hu
Iowa State University
International Conference on Icing of Aircraft, Engines, and Structures