Experimental study and numerical simulation of interfacial area transport of bubbly flow

Abstract

Measurement and numerical simulation of the interfacial area concentration and the void fraction were carried out to develop transport equation of interfacial area concentration to fulfill the requirements of an improved prediction accuracy of gas-liquid two-phase flow behavior. Measurements in a vertical upward air-water two-phase flow were conducted at the conditions of ambient temperature and atmospheric pressure. Test section was a round tube of 50 mm in inside diameter. The superficial gas velocity and the superficial liquid velocity ranged from 0.02 to 0.12 m/s and from 0.17 to 0.85 m/s, respectively. Two types of bubble generator were used in this study. One is that air was injected from the wall of the flow channel to the water (wall injection type). The other one is that air was injected from the pipe located at the center of the flow channel (pipe injection type). Measurements of the void fraction and the interfacial area concentration were performed using double sensor electrical resistivity probe at five axial locations of z = 45, 275, 575, 805, and 2365 mm for the wall injection type of bubble generator and z = 110, 410, 640, 1170, and 2230 mm for the pipe injection type of bubble generator, and transverse locations from r = 0 to 23 mm. In the numerical simulation, a transport equation of interfacial area concentration was developed in the previous study. This equation is validated by the previous and present experimental data. Consequently, good agreement is obtained between these results.

Keywords

• two-phase flow
• interfacial area concentration
• void fraction
• bubbly flow
• wall peak distribution
• core peak distribution