Numerical simulation of stratified waxy crude oil and water flows across horizontal pipes in the presence of wall heating
Abstract In the present work, a 3D numerical study was carried out to investigate the stratified flow of waxy crude oil water through a horizontal pipe with a contraction expansion placed in its midsection. Moreover, a uniform heat flux was applied to the pipeline wall to investigate its effect on the overall pressure drop across the pipeline and the two phase flow pattern. Waxy crude oils are highly viscous fluids, and they exhibit non Newtonian viscoplastic flow behavior. The governing equations of such non Newtonian multiphase flows were discretized and solved using the finite volume method on a structured numerical grid. The volume of fluid (VOF) method was utilized to capture the oil water interface. Waxy crude oil flowed in the laminar regime while a turbulent water flow field was assumed, and it was modeled using the well known SST k o turbulence model. The effect of several parameters, such as heat flux, wax content of the crude oil, and oil inlet velocity, have been studied comprehensively. The results revealed that the overall pressure drop was extremely sensitive to the wax content. Moreover, the simulation results indicated that using a relatively low uniform heat flux can reduce the pressure drop, up to 25% Finally, it is shown that by increasing oil velocity at the inlet, pressure drop monotonically increased.