Analytical and Level Set Method-Based Numerical Study for Two-Phase Stratified Flow in a Pipe

A nondimensional analytical study for fully developed and three-dimensional numerical study of developing viscosity stratified flow is presented, at various values of viscosity ratio eta, inlet area fraction of the less viscous fluid alpha ( 1,in ), and Reynolds number. With increasing alpha ( 1,in ), a change in the trend of axial variation in interface-from inlet to the fully developed region-is found at alpha ( 1,in )=alpha ( 1,in,c ). With increasing eta, development length is found to asymptotically decrease for alpha ( 1,in )=0.2 and increase for alpha ( 1,in )=0.5 and 0.8. A physical model for flow development is also presented for single- and two-fluid flow. A favorable operating condition to reduce the cost of transportation of more viscous fluids by pipe is proposed.