A new correlation for post-dryout heat transfer in upward vertical flow

Abstract

The present study established a new experimental databank of stable post-dryout (PDO) heat transfer which contains 31,603 data points in total. It is demonstrated by the assessment work with the new databank that previous PDO heat transfer prediction methods could not provide high prediction accuracy to various working conditions. Therefore, this study aims to develop a universal correlation for stable PDO heat transfer. With effect of convective and radiation heat transfer considered, a new prediction model for stable PDO heat transfer is developed, which is a dimensionless one and independent to upstream information. By identifying significant dimensionless parameters with Spearman’s rank correlation coefficient method and the group-wise statistic method, three dimensionless parameters (ReTP, PrW, and xe) are selected to establish the new PDO correlation. Though developed from water experiments for vertical flow in uniformly heated round tubes, the new correlation shows good predictive capability when validated against water experiments with non-uniform heating and R134a experiments with uniform heating, which means the new correlation can be applied to various working conditions. However, if applied to cryogenic pipeline chill-down transient or nuclear power plant accident scenarios, validation with transient experiments needs to be completed in the future.