Condensation and Subsequent Icing on Structured Plate and Glass Surfaces in Low-Speed Flows – An Experimental Study
Abstract
Condensation and subsequent icing are critical phase change processes occurring in solar thermal collector physics. Droplets and ice can have a significant impact on solar yield and dropping liquids can lead to a considerable deterioration of coated metal sheets often found in those devices. Therefore it is of utmost importance to understand condensation and the onset of icing and its dependence on relative humidity, flow speed, turbulent structures in the flow and both the surrounding and the plate temperature. In this contribution we focus on the promising application of microstructures in the effected regions of the collector and the utilization of different glass surfaces. The condensation and icing processes in driven turbulent flows on plates and glasses exhibiting varying contact angles due to different surface structures are monitored using high speed and thermo camera visualization techniques. The results will add to the understanding of condensation and icing processes on micro structured plates and glasses and provide the basis for numerical simulations, which will be capable of predicting onset-times, film- and ice-thickness estimations leading to energy efficient and cost-effective designs.