Abstract
The results of a study of heat transfer and hydrodynamic phenomena during flow of an air-water mist across a heated, horizontal cylinder are reported.
Local and average heat-transfer coefficients have been obtained, under conditions of constant heat flux, on the outer surface of a 19-mm outside diameter cylinder. Air flow rates corresponding to approach velocities of 20–75 m/s have been explored with mixture qualities in the range 0–9 per cent by weight of liquid phase.
Heat-transfer coefficients were found to be strongly dependent on mixture quality, and increases in the average value of the surface heat-transfer coefficient of twenty times the corresponding dry gas values were recorded with mixture qualities approaching 9 per cent by weight of liquid.
Under all conditions explored, a liquid layer was observed to form over the front half of the tube, between forward stagnation and separation. An intense bouncing or splashing action of droplets impinging on this layer was observed and measured.
Average values of surface heat-transfer coefficient were found to be correlated in terms of the quality and Reynolds number of the mixture and of Nusselt numbers based on average and stagnation point heat-transfer coefficients.
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