Air-water Annular Two-phase Flow in a Horizontal Tube : 2nd Report, Circumferential Variations of Film Thickness Parameters

Abstract

Experimental investigation was made on circumferential variations of the characteristics of a liquid film formed on the inner surface of a horizontal tube of 26.0 mm I.D. in which air and water flowed concurrently. Superficial velocities of the both phases ranged 10∼50 m/s for air and 0.006∼0.40 m/s for water. The flow pattern concerned was mainly an annular flow. Annular flow is subdivided into two regions characterized by liquid slug like frothy liquid lump (AF-region) and disturbance wave (AD-region). Classification can be made by examining the shape of the cumulative wave frequency distribution, plotted on normal probability paper against the radial distance from tube inner wall. A new method is proposed for separating base film from disturbance wave, which is processed on the wave frequency distribution chart. Experimental data are presented on principal parameters of liquid film such as thickness of base film, disturbance wave-height, -frequency and -velocity. A consideration is also made on the liquid transportation in disturbance wave region.