A new correlation of two-phase frictional pressure drop for evaporating flow in pipes

Flow Patterns, Void Fraction and Pressure Drop in Gas-Liquid Two Phase Flow at Different Pipe Orientations

“…However, more experimental data is required in the low region of void fraction typically a \ 0.5 in both upward and downward inclined pipe orientations to validate and further improve their performance in these orientations. It is observed that, the correlation of [107] has good potential to predict the two phase frictional pressure drop and may be considered for further analysis and modification to account for the two phase flow of different refrigerants. This work is concluded by providing two sample problems that deal with air-water and refrigerant two phase flow under different operating conditions.…”

“…where Y is same as that of [20] and La is the Laplace number used by Xu and Fang [107] Applicable for R12, R134a and R113 in smooth tubes with …”

“…The top performing correlations for two phase flow of nine different refrigerants in horizontal pipe orientation are shortlisted in Table 4.17. It is found that the correlations of [28,107] are among the top performing correlations for majority of the refrigerants. The best performance is given by the correlations for R404A and R407 C with 26 and 42 data points, respectively.…”

“…In comparison to other refrigerants, all the correlations considered in this chapter are found to give less accuracy for refrigerant R134a with 514 data points. Overall it appears that the correlations of [28,107] have potential to predict the two phase frictional pressure drop correctly over a wide range of refrigerants and hence must be considered for any further modification to improve their accuracy. Although the correlation of [107] is not among the top performing correlations for R123, R407C, and R507 it predicts 61, 81 and 67 % of data within ±30 % error bands.…”

“…Overall it appears that the correlations of [28,107] have potential to predict the two phase frictional pressure drop correctly over a wide range of refrigerants and hence must be considered for any further modification to improve their accuracy. Although the correlation of [107] is not among the top performing correlations for R123, R407C, and R507 it predicts 61, 81 and 67 % of data within ±30 % error bands. A more comprehensive analysis is required to determine the accuracies of these correlations for different flow patterns or alternatively different ranges of the void fraction for both air-water and refrigerant data.…”