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A Revised Analysis of the Effect of Surfactants on Two‐Phase Phenomena in Horizontal Air‐Water Pipe Flow
Author(s) -
Spedding P. L.,
Hand N. P.
Publication year - 1997
Publication title -
developments in chemical engineering and mineral processing
Language(s) - English
Resource type - Journals
eISSN - 1932-2143
pISSN - 0969-1855
DOI - 10.1002/apj.5500050308
Subject(s) - drag , mechanics , ripple , two phase flow , surface tension , materials science , pulmonary surfactant , flow (mathematics) , volumetric flow rate , thermodynamics , physics , power (physics)
Flow regimes, hold‐up and pressure loss measurements in two‐phase air‐water co‐current horizontal flow have shown that the effect of surfactant was to: a. suppress the formation of ripples or gravity waves; b. progressively extend the range of the smooth stratified pattern at the expense of the ripple flow regime, as the gas rate was increased; c. increase the liquid hold‐up above that for water alone over the wavy regimes from the top end of the smooth stratified pattern to the onset of film‐plus‐droplet flow, and there was a corresponding reduction in pressure loss. The mechanism responsible for the suppression of waves resulted in a reduction in the ability of the gas to scour out the liquid. The fundamental cause for these effects was linked to local variations in surface tension as the surface film on the liquid was alternatively expanded and compressed by the ripples. Additional effects of surfactant at other flow conditions were that: d. drag reductions occurred in the slug and plug regimes with the surfactant affecting the liquid slug nose regions; e. drag reduction also occurred in the annular regime at high gas and liquid flow rates, caused by the damping of waves at the base of the annular film. These results help explain a number of apparent anomalies presented in the literature.