Void fraction measurement in modeled two-phase flow inside a vertical pipe by using polyethylene phantoms

•The homogenous, stratified and annular two-phase flow regimes were modeled in a vertical pipe.•Polyethylene phantoms were used to model two-phase flow inside the pipe.•Transmitted and scattered gamma rays through the modeled pipe were measured.•Numerical modeling was done by using MCNP code.•To predict the void fraction inside a vertical pipe an innovative correlation was presented.

The main purpose of this study is experimental and numerical void fraction measurement in two-phase flow inside a vertical pipe by using gamma-ray. Three types of flow regimes including homogenous, stratified and annular were modeled in a vertical pipe by using polyethylene phantoms. These three flow regimes are basis regimes in two-phase flow and the other flow regimes are incorporated of these patterns. For all three modeled flow regimes all transmitted and scattered gamma rays in all directions were measured by setting a gamma ray source and detector around the pipe. Numerical modeling was done by using MCNP code to improve the accuracy and validation of experimental results. Finally, innovative correlations to predict the void fraction in two-phase flow in a vertical pipe was presented.