Core‐annular two‐phase flow in a gently curved circular channel

Abstract

The velocity field of a core‐annular two‐phase flow through a curved channel is investigated. The case of fully developed flow with a concentric, circular fluid–fluid interface is considered. In the limit of a gentle axial curvature of the curved channel, an analytical solution is obtained in the form of a regular asymptotic expansion to first order. The condition on the physical parameters for the core to be concentric and circular is derived by accounting for the normal stresses at the interface. Two key features of the flow, the secondary circulations and the redistribution of the axial velocity, are described in detail. The viscous coupling of the two fluids at the interface leads to a variety of circulation patterns and axial velocity profiles, depending on the system parameters. The parameter space is divided into different regions using analytical conditions at the transition between flow regimes. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4871–4886, 2013

Numerical study of laminar core‐annular flow in a torus and in a 90° pipe bend

“…They presented in their paper a circulatory flow regime map on the ( k , )‐plane at various values for Re 1 and Re 2 . For the details we refer to the paper by Picardo and Pushpavanam …”

“… Secondary flows for the case and k = 0.5 according to Picardo and Pushpavanam . I indicates the inner side of the torus and O the outer side.…”

“…A different (original and interesting) approach to study core‐annular flow in a curved pipe was made by Picardo and Pushpavanam . They focused on the case of a fully developed laminar core‐annular flow in a torus with a concentric, circular core.…”

Vertically stratified two-phase flow in a curved channel: Insights from a domain perturbation analysis

“…This inter-fluid interaction is responsible for a range of flow patterns in core-annular flow in a curved circular channel -recently studied by Picardo and Pushpavanam, 10 using an asymptotic solution at low Reynolds numbers. They identified five different flow patterns; we expect a similar variety of circulation patterns when the fluids are vertically stratified.…”

“…The additional mixing in curved microchannels will enhance the performance of these devices. 10 With the aim of elucidating the underlying physical mechanisms, we address the problem of vertically stratified flow in the limit of a gently curved channel and low Reynolds numbers. We apply the method of domain perturbations, 20 which approximates the solution of the velocity field and interface location as a small deviation from their straight channel counterparts.…”