This analysis gave a better understanding of the performance of the correlations when evaluated against different pipe diameters, fluid combinations and the system pressures. The accuracy and hence the performance of the void fraction correlations is judged in terms of percentage error and RMS error. The void fraction correlations are further assessed against four specified ranges of the void fraction 0–0.25, 0.25–0.5, 0.5–0.75 and 0.75–1, respectively. These four ranges are selected in accordance with the approximate range of the void fraction associated with individual flow patterns. In the present study it is observed that the void fraction range of
0 < a 6 0.25 approximates the bubbly flow pattern while falling film and annular flow regimes approximately cover the void fraction range of 0.75 < a < 1. The intermediate range of the void fraction is observed to be occupied by the slug and froth flow, respectively. This approximation for more than 90% of the data is well within ±15% of the experimental results obtained in the present study as well as is in consensus with the results of Oshinowo [21] and Yijun and Rezkallah [6]. Thus this two step scrutiny proved useful for getting unbiased results and analyzes the performance of the void fraction correlations.