Evaluation analysis of correlations for predicting void fraction of condensation hydrocarbon refrigerant upward flow in a spiral pipe

Accurate prediction of void fraction for condensation hydrocarbon refrigerant upward flow in a spiral pipe is very important for the tube-side design of spiral wound heat exchange (SWHE) using in liquid natural gas (LNG) plants. Although scores of void fraction correlations have been developed until now, most of them are focus on two-phase flow in straight tubes and their applicability to spiral pipes needs to be evaluated. In this paper, the condensation void fraction characteristics were numerically investigated based on the verified model. 455 numerical data points of six refrigerants were obtained, under different operating and structural parameters. Based on these data, 96 void fraction correlations were evaluated, which covered the types of homogeneous, slip-ratio, Kαv,H, Lockhart-Martinelli parameter based, drift-flux, general and implicit, and finally the best five correlations were recommended which can well predict condensation void fraction in a spiral pipe within ±5% error. This study will provide some constructive instructions to predict void fraction for condensation hydrocarbon refrigerant upward flow in a spiral pipe, which is helpful in designing more effective SWHE used in large-scale LNG plants.