Forced convection condensation of steam in the presence of multicomponent noncondensable gases inside a horizontal tube

• Published in: International journal of heat and mass transfer 2017-01, Vol.104, p.1110-1119
• Main Authors: Xu, Huiqiang, Gu, Haifeng, Sun, Zhongning
• Format: Article
• Language: English
• Subjects: Condensation; Heat transfer correlation; Horizontal tubes; Multicomponent noncondensable gases
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2016.09.031

•Experimental study on condensation of steam/air/helium was made in horizontal tube.•Effects of subcooling and velocity on condensation vary in different flow regime.•The increase of helium fraction always promotes the condensation heat transfer.•The correlation in present study predicts heat transfer ability with ±20% error. An experimental investigation on condensation heat transfer characteristics of steam in the presence of multicomponent noncondensable gases in a horizontal tube is conducted in the present research. The experimental runs are carried out at a volume ratio of helium and noncondensable gases varying from 0% to 90%, the mixture gases pressure between 0.13 and 0.2MPa, over the mixture gases velocity changing from 8 to 34m/s, covering all the major flow patterns inside a pipe. The effects of inner wall subcooling, mixture gases velocity and pressure on local heat transfer coefficient have been analyzed for annular, wavy and stratified flow. The change of the condensation heat transfer capacity for different volume ratios of helium in the noncondensable gases have been studied at the same time. The results indicate that the local heat transfer coefficient increases with the increasing wall subcooling for annular and wavy flow but decreases for stratified flow. With the flow regime transforming from annular to stratified flow, the active influence of the gases velocity is gradually weakened and the local heat transfer coefficient even starts to decrease when it reaches stratified flow. For all flow patterns, the increases of helium volume fraction and mixture gases pressure always enhance the condensation heat transfer. Based on the experimental analysis, an empirical correlation for predicting the local heat transfer coefficient is proposed. The comparison of the calculated results and the experimental data shows that the present correlation can give satisfactory engineering accuracy.