DISPLACEMENT OF ONE NEWTONIAN FLUID BY ANOTHER - DENSITY EFFECTS IN AXIAL ANNULAR-FLOW

The arbitrary Lagrange-Euler (ALE) finite element technique is used to simulate 3-D displacement of two immiscible Newtonian fluids in verti cal annular welts. For equally viscous fluids the effect of distinct f luid densities is investigated in the region of low to intermediate Re ynolds numbers. Comparison with a simple theory for drainage of thin f ilms is performed. It is found that recirculations deform the fluid-fl uid interface significantly in situations dominated by buoyancy forces . Also, a deviation from the concentric annular geometry is shown to i nduce azimuthal transport of fluid. Finally, the efficiency of the dis placement is analysed for Various flow situation. Copyright (C) 1996 E lsevier Science Ltd.