A Comparative Study on the Pressure Drop of Air-Water Flow

Two-phase pressure drops have been measured in a vertical tube of inside diameter 24.5 mm in the liquid mass velocity range up to 3600kg/m2sec. The data are well correlated by the Lockhart-Martinelli method over the whole range of mass velocities. Martinelli's multiplier for the two-phase pressure drop, φL, does not vary with the total or liquid mass velocities in contrast with Petrick's results for rectangular channels. The results obtained were compared with other data and a fairly good agreement was found. The relation between a two-phase friction factor and Reynolds number, each based on the linear velocity of the liquid phase is almost identical to that for a single phase flow, i.e., the Blasius'equation, except in the case of very high air-velocities.