Sensitivity of two-fluid model calculations to two-group drift-flux correlations used in the prediction of interfacial drag

Void fraction prediction of the one-dimensional two-fluid model has been evaluated utilizing a computational tool developed in MATLAB. Various drift-flux correlations, specifically those of Ishii, Kataoka and Ishii, Chexal-Lellouche, Hibiki and Ishii, Shen et al., and Schlegel et al., have been used in the calculation of interfacial drag. The uncertainty in the void fraction prediction by the two-fluid model has been evaluated for each of the specified models under one-group conditions for the gas phase. In addition, several two-group drift-flux models have been implemented for the prediction of interfacial drag, and the accuracy has been compared to the accuracy of the one-group predictions. The results indicate that drift-flux correlations in the same "family" show minor improvements when using updated models. The models of Hibiki and Ishii and Schlegel et al. show the best results of the models included in this study. Some shortcomings were observed for the Chexal-Lellouche correlation. The two-group approach has shown significant error reduction over one-group models. The results highlight the need for properly formulated drift-flux correlations based on physical principles rather than curve fits, as those curve fits can hide compensating errors. Additional data in large diameter pipes, collected with steam-water systems at various pressures, would be extremely valuable for further analysis.