Analysis of air-steam condensation tests on a vertical tube of the passive containment cooling system under natural convection

This paper presents an analytical study of the air-steam condensation on a vertical tube of a passive containment cooling system under natural convection conditions. From JNU (Jeju National University) condensation tests, the heat transfer coefficient (HTC) of steam condensation in the presence of air was measured on an outer surface of a cylindrical tube of 40 mm in outer diameter and 1.0 m in length. Using the experimental results from the JNU tests and those obtained in MIT, TIT, and UW-Madison, the validity of empirical correlations to determine condensation HTCs on condenser tubes with different lengths was evaluated. In addition, the mechanistic models using the heat and mass transfer analogy were applied to calculate the condensate rate of air-steam mixture. Combined with a couple of empirical heat transfer expressions for heat and mass transfer analogy, three different formulations to compute the vapor mass flux were applied and their prediction results were compared to the experimental results by JNU tests and MIT tests. The experimentally determined Sherwood number was also presented for both experiments, provided one employs the Collier/Stephan modeling to calculate the mass transfer rate by air-steam condensation. (C) 2019 Published by Elsevier Ltd.