Countercurrent flooding limited critical heat flux in vertical channels at zero inlet flow

Abstract

In order to understand the characteristics of countercurrent flooding limited critical heat flux (CHF) in a heated channel with a closed bottom and to find more general understanding of the minimum CHF at countercurrent flow, the available CHF data for tubes, annuli and rectangular channels are compared with the predictions by various existing flooding correlations. Some of existing correlations show reasonable predictions in their original form but would give better predictions by modifying some correlation constants. A modified coefficient of C-w(2) for Wallis flooding correlation is proposed for general use in predicting the flooding limited CHF with an RMS error of 18.8% for three kinds of test section geometries under low pressure conditions. (C) 1997 Elsevier Science Ltd.