Spray Cooling with Formation of Liquid Film. Distribution of Heat Transfer Coefficient in High-Temperature Region.

Abstract

This report presents experimental results on the distribution of the heat-transfer coefficient along a large flat plate in the high-temperature region of spray cooling. The results show that the heat-transfer characteristics of spray cooling in the high-temperature region can be divided into the impinging and the wall regions. In the impinging region, with increasing distance from the stagnation point of the spray flow, the local heat-transfer coefficient decreases rapidly with the decrease of the local droplet-flow rate and the minimum temperature of the high-temperature region increases due to the propagation of the wetting front. However, in the wall region, the local heat-transfer coefficient approaches a constant value dependent on the total droplet-flow rate, and the minimum temperature is independent of the distance from the stagnation point.