Godbole et al. [11] and Bhagwat [31] presented a detailed performance analysis of the 52 void fraction correlations for upward and 26 correlations for downward flow, respectively. The void fraction correlations were evaluated against the entire data set, individual data sets, different flow patterns and the four specified ranges of the void fraction. However, in the present study we limit our discussion on the performance of the void fraction correlations
for four specified ranges of the void fraction and present the results of the recommended top five performing correlations in upward and downward orientations, respectively. The results of the top five performing correlations in each specified range of the void fraction for vertical upward and downward orientations are presented in Tables 3 and 4, respectively.