Study of flow patterns and void fraction in vertical upward two-phase flow

Scope and Method of Study. An extensive literature search on flow patterns, void fraction and experimental data for vertical upward two-phase flow was done. Experiments were carried out for flow visualization and void fraction data. Flow patterns and flow pattern transitions were studied. Flow pattern transition theories from literature were modeled and tested against experimental data. Effect of diameter and gas phase density on flow pattern map was studied. Variation of void fraction in flow patterns was studied. Flow pattern specific and flow pattern independent correlations from literature were tested against experimental data.;Findings and Conclusions. Five distinct flow patterns were observed in the present study. Flow pattern map was developed based on the data of flow patterns. The details of experimental flow pattern transitions were discussed elaborately. The best flow transition theory was recommended for slug-churn and churn-annular flow pattern transition. Effect of diameter and gas phase density on flow pattern transition was analyzed and recommendations were given. The trend of void fraction in different flow patterns was reported based on the experimental data. The best correlations for prediction of void fraction were recommended for each flow pattern. The best flow pattern independent correlation for prediction of the entire range of void fraction data was recommended.