Simultaneous entrainment of oil and water droplets in high Reynolds number gas turbulence in horizontal pipe flow

We develop a 1D cross sectional concentration profile model for oil and water droplets that coexist in the turbulent gas phase (of Re ∼ 106) in near horizontal stratified pipe flows. Entrainment of the oil and water mixture from a liquid film near the bottom of the pipe into the gas is modeled based on earlier single-fluid entrainment correlations. A Gamma distribution for the droplet sizes based on the breakup of liquid filaments, is adopted. An explicit algebraic–exponential formula for the total concentration profile for either phase can then be derived.We find evidence for entrainment controlled by the dominant fluid (oil), and the minority fluid (water) is entrained and carried more passively by the majority fluid. The self similarity and scaling properties of the droplet distributions are demonstrated, and the results are consistent with the presence of two separate oil and water droplet populations.The experimental concentration profiles were obtained by using an iso-kinetic probe. The fluids were Exxsol-D80 and water, and the gas was SF6, to emulate high pressure field conditions. The liquid fractions were 1% and 5%, and the pipe diameter was 10 cm.

► We model entrainment of oil and water droplets that coexists in the gas phase. ► The concentration profile model accounts for a range of Stokes numbers. ► We find evidence for separate oil and water droplet populations. ► The self similarity properties of the droplet distributions are demonstrated. ► The experimental concentration profiles were obtained by an iso-kinetic probe.