The effect of volumetric quality on heat transfer and fluid flow characteristics of air-assistant jet impingement

Heat transfer characteristics of air-assistant water jet impingement was experimentally investigated under a fixed water flow rate condition. Water and air were used as the test fluids. The effects of volumetric quality (beta = 0-0.9) on the Nusselt number and pressure were considered. The results showed that the stagnation Nusselt number increased with volumetric quality, attained a maximum value at around 0.8 of the volumetric quality, and then decreased. The stagnation Nusselt number of the air-assistant water jet impingement is governed by the stagnation pressure. Based on the experimental results, a new correlation for the normalized stagnation Nusselt number is developed as a function of the normalized stagnation pressure alone. In addition, the lateral variation of Nusselt number is governed by hydraulic jump radius. (C) 2016 Elsevier Ltd. All rights reserved.