The experimental and predictive study of void fraction is very important for the natural circulation and accident analysis in nuclear reactors. However

most of the researches on void fraction were carried out with high mass flux

and the predictions of existing void fraction correlations are quite different in low-flow two-phase flow. Void fraction with low mass flux in adiabatic tube is investigated using single-sensor optical probe in this paper. And then average void fraction is obtained through the integral calculation of local void fraction in the cross-section. The comparisons of existing void fraction correlations with low mass flux experimental data show that most of the correlations overestimate the experimental data

and the predictions of Chexal et al.

Dix and GE-Ramp correlations fit the data quite well. Chexal et al. correlation is therefore suggested for the prediction of void fraction with low mass flux two-phase flow according to Vijayan’s work.