Two-phase flow pressure losses in a horizontal impacting T-junction

The present paper reports further analyses of the two-phase pressure drops experimental data obtained in a horizontal impacting T-junction. A mixture of air and water at ambient temperature and pressures up to 1.5 bar is generated inside a mixer, which is fed by a compressed air system and a centrifugal pump. Superficial velocities of air and water in the inlet pipe are varied up to a maximum of 35 m/s and 3.5 m/s respectively. Each branch has got four pressure taps which can be connected to both differential and absolute pressure transducers. These measurements allow us to determine the pressure behaviour along the pipes and to extrapolate the pressure losses between the inlet and the branches. Pressure drops, that are extrapolated in the junction, are analysed and the irreversible component (pressure loss) is evaluated. The two-phase pressure losses are compared with the Chisholm two – phase multiplier and with the prediction of the El-Shaboury et al. model, and several correlations for the pressure loss coefficients are tested: the loss coefficients are expressed as a function of the Reynolds number, as in the El-Shaboury et al. approach, and the dependence of loss coefficients on the inlet void fraction, flow quality and Martinelli parameter is also analysed.