Spurious Current Suppression in VOF-CSF Simulation of Slug Flow through Small Channels

Abstract

A numerical treatment is proposed to minimize the creation of unphysical, spurious currents in modeling liquid–gas slug flow using the volume of fluid-continuum surface force (VOF-CSF) method. An elongated gas slug drawn into a small circular channel initially filled with liquid is considered. To suppress spurious currents formed by numerical errors in calculation of the surface tension force at small capillary numbers (Ca < 0.01), an artificial relative reference frame is specified with motion in a direction opposite to the flow. An increase in the local relative velocity magnitude near the interface is demonstrated to be the key mechanism for spurious current suppression. A comparison of simulations performed with and without this treatment shows that spurious currents are eliminated at Ca = 0.0029; liquid film thickness, gas slug velocity, and liquid-phase circulation near the leading slug interface are preserved and the computed values agree with the literature. This demonstrates that the proposed moving reference frame method does not influence the computed physical phenomena of interest while suppressing unphysical spurious velocities.

Acknowledgments

This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) Microsystems Technology Office's (MTO) Intrachip/Interchip Enhanced Cooling (ICECool) Fundamentals program under the Cooperative Agreement No. HR0011-13-2-0010. The content of the information does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred. Distribution Statement A—Approved for public release; distribution unlimited.

Notes

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