Pressure Drop Correlations for Inclined Two-Phase Flow

Pressure drop behavior in two-phase inclined flow was studied. For bubble and slug flow, a no-slip friction factor calculated from the Moody diagram was found adequate for friction head loss calculations. In downhill stratified flow, the friction pressure gradient is calculated based on a momentum balance equation for either phase assuming a smooth gas-liquid interface. For this calculation, a prior knowledge of the liquid holdup is needed. For annular-mist flow, a friction factor correlation is presented that is a function of holdup ratio and no-slip Moody friction factor. Results agree well with the experimental data and correlations were further verified with Prudhoe Bay and North Sea data.