COMPARATIVE STUDY OF WATER VAPOUR CONDENSATION FROM HUMID AIR FLOWING ON A VERTICAL PLATE AND A PIPE IN A LAMINA ALONG WITH CFD SIMULATION

The Condensation of water vapor from humid air takes place in thermal systems. Theoretically the problem of water vapor condensation from humid air flowing on a vertical pipe is tackled and vertical plate in laminar flow is formulated. The vapor flow on the plate condenses at dew point temperature of the vapor air mixture. The vapor condensing will diffuse on to the wall of vertical plate and vertical pipe through a non-condensable gas film of high concentration air. The condensing vapor releases both the convection and latent heats to the wall of the plate and from inlet of pipe. Thus the problem is treated as a combined heat and mass transfer problem in both cases. The mass, momentum and energy balance equations for the vapor air mixture flowing on the plate and in the pipe and diffusion equation for the vapor species are considered. The flow of the condensate is laminar. The momentum and energy balance equations for the condensate film are also considered. The gas phase and liquid phase equations are solved by a finite difference method. The system parameters considered are temperature, gas phase Reynolds number and relative humidity of air at the inlet of plate and pipe. In both the cases, the numerical results are obtained to estimate the local condensation Nusselt number, condensate film thickness and gas-to-liquid interface temperature for different system parameters. The gas phase convection Nusselt and Sherwood numbers are also computed. The part modeling of plate and pipe is designed in CATIA V5 R19. The CFD simulation of plate and pipe is done with a comparative study.