Heat transfer behaviour of a dilute impinging air-water mist jet at low wall temperatures

This paper presents experimental work on the heat transfer characteristics of a dilute impinging air water mist jet. Time-averaged heat transfer measurements are reported, as well as simultaneously obtained high-speed shadowgraph imaging flow visualisation and heat transfer measurements; images of the mist jet impingement and the liquid film that forms on the impingement surface are also included. It is determined that the surface liquid morphology varies with mist loading fraction, and that the heat transfer behaviour of the mist jet reflects these changes. Intermittent thermal disturbance caused by the impingement of the mist jet droplets is proposed as the dominant heat transfer mechanism when the mist loading fraction is very low; as the mist loading fraction increases, evaporation from the surface liquid film and convective cooling due to the film flow become more significant. (C) 2017 Elsevier Ltd. All rights reserved.