Heat Transfer to Low Pressure Sprays of Water in a Steam Atmosphere

Abstract

An investigation is made into the mechanism of the flow of water, and the heat transfer from steam to the water, from the coarse spray nozzles used in commercial apparatus. The heat transfer can be regarded as taking place in two phases, the film phase and the drop phase, corresponding to the flow of water as a film and in drops. For a range of pressures up to about one atmosphere, the first phase is the more significant so that the use of a larger number of nozzles (to produce smaller drops) becomes of secondary importance in heat transfer, where the initial temperature difference and velocity are the important parameters. Methods of arriving at the values of the various dynamical stages are demonstrated. Heat-transfer coefficients in the film phase are of a much greater order than those used in conventional tube flow arrangements, although the physical relations are the same. The drop-phase coefficient has also been measured.