CS-21 Xist Thermal Predictions of Horizontal Shellside Condensation with Subcooling

S. Talapatra

HTRI collected data in a horizontal E-shell exchanger with vertical-cut baffles, obtaining varying degrees of subcooling at the exchanger outlet for water, n-pentane, p-xylene, and  a binary mixture of n-pentane/p-xylene. Liquid level measurements along the length of the exchanger confirmed the presence of shellside flooding. Xist predicted the heat transfer area fraction under submergence within ±10% of most measured values, even for cases with 30 – 40% shell submergence and up to 60 °C subcooling. The thermal predictions did not exhibit any deterioration with an increase in the extent of shellside flooding and associated subcooling. Xist predicted overall heat transfer coefficients for water and p-xylene within ±20% and those for n-pentane and n-pentane/p-xylene within ±40%, with a clear trend of underprediction increasing with increasing flow rates or higher shear. Underprediction of  the shellside heat transfer coefficient is postulated to be due to direct contact heat transfer, at least in part. This report includes a new descriptive model for shellside condensation  with subcooling.