Interfacial condensation for countercurrent steam–water stratified wavy flow in a horizontal circular pipe

We experimentally investigate the interfacial condensation heat transfer for a steam–water countercurrent stratified flow in a horizontal pipe. In contrast to the previous work of Chu et al. [I.C. Chu, S.O. Yu, M.H. Chun, Interfacial condensation heat transfer for countercurrent steam–water stratified flow in a circular pipe. J. Korean Nucl. Soc. 32 (2) (2000) 142–156] that investigated only the interfacial condensation heat transfer in a stratified smooth flow in a horizontal pipe, this work investigates the steam–water stratified wavy flow. A total of 105 local interfacial condensation heat transfer coefficients for a wavy interface have been obtained. The parametric effects of the flow rates of steam and subcooled water and the degree of subcooling on condensation heat transfer were examined. The empirical Nusselt number correlation was developed on the basis of the bulk flow properties. This correlation agrees with the experimental data within ±32% with a RMS error of 16.2%. Its applicable ranges for a steam–water countercurrent stratified flow in a horizontal pipe are as follows: the ranges of Reynolds numbers are 4000–14 000 for the water and 12 000–23 000 for the steam, and the Jakob numbers for the water are 43.5–180.