The Effect of Vapor Velocity Profile Shape on Flow Film Boiling From Submerged Bodies

An analysis of subcooled flow film boiling from submerged bodies that includes the effect of nonlinearity of the vapor film velocity profile is performed. The angle at which vapor flow reversal occurs on the back of the body is predicted by the analysis. A comparison of the predicted vapor flow reversal angle to the wake formation angle observed for flow boiling over spheres indicates that wake formation occurs a few degrees downstream of the vapor flow reversal point. A comparison of the analysis to available experimental data shows that heat transfer results based on a quadratic vapor velocity profile compare much better with experiments than do previous analyses. The heat transfer results for linear and quadratic vapor velocity profiles become virtually identical as subcooling increases.