Two‐phase pressure drop in vertical crossflow across a horizontal tube bundle

An experimental investigation has been made to evaluate the friction, acceleration, and hydrostatic pressure drops in two‐phase vertical crossflow across a horizontal tube bundle through the measurement of the void fraction and determination of the two‐phase friction multiplier. The void fractions were found to increase with increasing mass velocity for a fixed quality level. The two‐phase friction multiplier increased with increasing mass velocity for a fixed value of the Martinelli parameter in both slug and spray flow and decreased with increasing mass velocity in bubbly flows. The void fraction and two‐phase friction multiplier data were correlated and used to predict with very good results the total pressure drop occurring in simulated diabatic flow tests and in actual diabatic tests using R‐113.