Axial development of interfacial area and void concentration profiles measured by double-sensor probe method

Abstract

Interfacial area concentration is an important parameter in modeling the interfacial transfer terms in the two-fluid model. In this paper, the local geometric and statistical characteristics of upward co-current dispersed bubbly flow in a pipe have been studied both at the entrance ( L D = 8 ) and at a region far away from the entrance ( L D = 60 ). The test section was a 5.08 cm i.d. and 375 cm long Lucite pipe. Four liquid flow rates ranging from 0.1 to 1.0 m s −1 were used in combination with four different gas injection rates ranging from 0.02 to 0.1 m s −1. A double-sensor probe was employed to measure the radial profiles of void fraction, interfacial area concentration, Sauter mean diameter, bubble velocity and bubble frequency. The wall peak of the void fraction profile was established within a short distance from the entrance. The flow characteristics changed very little from the entrance region to the fully developed region except for the flow case of j 1 = 0.1 m s −1. The area averaged flow quantities were also presented.