An experimental study is conducted and a mechanistic model is developed to investigate the effect of noncondensable gas in a passive condenser system. A vertical condenser tube was submerged in a water pool where the heat from the condenser tube was removed through boiling heat transfer. Data was obtained for various process parameters such as inlet steam flow rate, noncondensable gas mass fraction, and system pressure. Degradation of the condensation with noncondensable gas was investigated, where condensation heat transfer coefficient and heat transfer rate decrease with the noncondensable gas. It was found that the condensation heat transfer rate is enhanced by increasing the inlet steam flow rate and the system pressure. A mechanistic condensation correlation is developed which contains the major heat transfer components in its functional relationships. The heat transfers for the film region and the gas region sensible heat were modeled with the modified Nusselt solution and the single phase heat transfer correlations, respectively. The gas region condensation was correlated with bulk noncondensable mass fraction, gas region Reynolds number, and Jakob number. New correlation was compared with available experimental data and models. Mean errors of the correlation were found to be 4.7% and 13.4% for the tube average and the local condensation heat transfer coefficient, respectively.
Degradation of condensation heat transfer on a vertical cylinder by a light noncondensable gas mixed with air-steam mixtures
