The Drift Flux Model After Fifty Years: A Personal, Problem Solving Survey

Abstract

Offspring of the nuclear reactor industry and gas-oil production, multiphase fluids handling technology appears to have matured into an entirely new field of inquiry, most notably following broad acceptance of the drift flux and flow pattern concepts and their widespread integration into engineering calculations. The drift flux model (DFM), first suggested by Nicklin in 1962 and, soon after, adapted and developed by Professor Zuber’s research group at General Electric, enables calculation of “locally averaged” phase velocity. Further progress made in selection of the flow patterns, calculated for each section of the pipe, provided the key to properly assessing the terminal velocity of the discrete phase and the local phase distributions. The flow pattern concept was first introduced by Canadian Charles Govier to describe oil-water laboratory experiments, then by Hewitt-Roberts and Baker in 1954. A decade later, the team of Dukler-Taitel-Barnea developed the qualitative flow pattern concept into a quantitative roadmap procedure leading to rational calculations of the local (cross-section averaged) gas-liquid flow geometry, or flow pattern. The homogeneous gas-liquid flow, presuming the equality of gas and liquid velocities, a simplification broadly accepted during the early days of two-phase flow engineering, came to be regarded, due to Hinze’s work (Shell, 1955), as an identifiable region in the local flow map, reflecting turbulent and high-shear breakup of the discrete phase. To illustrate the usefulness, validity, and importance of the DFM, and mechanistic modeling using the DFM, as well as the salient work of Prof. Zuber on boiling instability this paper discuses reduction of potential explosive droplet boiling risk during multiphase pumping of high–gas-oil ratio mixtures. To assess critical operating conditions of the multiphase pumps, the Ishi-Zuber criteria developed during 1970 for assessing potential boiling instabilities were adapted to multiphase pumping/compression equipment and the results compared to field instability data. The elucidation of this problem relies heavily on the DFM and on salient research performed during 70s by Prof. Zuber’s team.