A Study of Shellside Condensation of a Hydrocarbon in the Presence of Noncondensable Gas on Twisted Elliptical Tubes

Experimental data were collected for one smooth round tube bundle and three twisted elliptical tube bundles using a kerosene mixture as a condensing vapor and air as a noncondensable gas. Experimental results showed that heat transfer for the twisted tubes was enhanced by a factor of 1.5–3 as compared to the plain tubes, depending on the specific tube geometry and process conditions. Heat transfer enhancement was found to increase with decreasing twist pitch, increasing tube ellipticity, and increasing mass flow rate. The presence of noncondensable gas was observed to significantly decrease condensation heat transfer performance due to the increase in mass diffusion resistance and lowering of the vapor condensation temperature at the vapor–liquid interface. Using the heat and mass transfer analogy method, a correlation for the condensation heat transfer coefficient of the mixture has been developed from the experimental data. Comparisons show that the predicative accuracy of the new correlation is within ±25% for the majority of experimental data.