Effect of Surface Roughness of Pipe on Residual Liquid after Passage of Gas Liquid Interface.

Abstract

A thin liquid film is left on wall after passage of a gas liquid interface front in a horizontal circular pipe filled up with water. The effect of the surface roughness of the inner surface of the pipe on the residual liquid film thickness is studied analytically and experimentally. Taking account of the increase of the pressure drop owing to the surface roughness of a wavy wall, the residual liquid film thickness on a wavy wall is analyzed by the same method as the thickness of film remaining on a surface of a solid withdrawn from a quiescent liquid. The numerical analysis of the pressure drop in a wavy wall channel is performed by an integral momentum method. The present study suggests that the surface roughness (2e) of the pipe effects on the residual liquid film thickness δ if δ<2e.