An Experimental and Analytical Study of Heat Transfer and Pressure Drop in Horizontal Annular Two-phase, Two-component Flow

The static pressure drop and both the local and average heat transfer coefficients were measured for the horizontal annular flow of water and air in a tube with an inside diameter of one inch. A correlation for the heat transfer coefficients was obtained. The pressure drop data agreed well with the Lockhart-Martinelli correlation and the prediction of the Wrobel-McManus wave roughness theory. A theory based on an axisymmetric model with no liquid entrainment was developed to allow predictions of local heat transfer coefficients. In comparing the predictions with the measured coefficients, 85% of the predictions were within plus or minus 60% of the measured values from horizontal flow and substantially better agreement resulted when the theory was modified empirically to take into account liquid entrainment and circumferential temperature variations. The theory was applied to conditions beyond the scope of the experimental program to predict the effects of varying heat flux, tube temperature, and tube diameter on the coefficients.