A new correlation of flow boiling heat transfer coefficients based on R134a data

As one of the most widely used refrigerants, R134a has been investigated extensively in the past 20 years, and research into R134a two-phase flow boiling heat transfer remains a hot spot. A number of correlations for two-phase flow boiling heat transfer have been proposed. However, a correlation with high prediction accuracy for R134a two-phase flow boiling heat transfer remains needed. The purpose of this work is to propose a better correlation for R134a two-phase flow boiling heat transfer. Based on the database consisting of 2286 data points of R134a two-phase flow boiling heat transfer compiled from 19 published papers, a new correlation for two-phase flow boiling heat transfer coefficient is developed. The new correlation takes advantage of the newly defined dimensionless number Fa that is highly related to flow boiling heat transfer. It has a mean absolute deviation (MAD) of 14.2%, with 74.4% of the sample having a relative deviation within ±20%, while the best one among 20 existing models available in literature only has an MAD of 34.9%, with 31.2% of the sample having the relative deviation within ±20%. The new correlation also shows high prediction accuracy for other refrigerants.