Condensation from vapor-gas mixture for forced downflow inside a tube

A theoretical analysis model for condensation from vapor-gas mixture for forced downflow inside a tube has been developed in this study. The model is mainly used to provide the detailed local heat transfer characteristics and carry out a parametric sets of calculation spanning the expected range of conditions for the SBWR condenser for steam-gas mixture to supplement the experimental data in support of GE's PCCS condensers design.;The development is based on steady state boundary layer conservation equations in two-dimensional (r, z) cylindrical coordinate system for liquid film and gaseous phase assuming smooth liquid film surface. The effects of liquid film surface waviness are treated by incorporating an empirical correlation for correcting the friction factor and hence the shear stress at the interface. For turbulent flow the low turbulent Reynolds number two-equation k-;In general the code can provide many local flow and heat transfer characteristics which are useful for the understanding of the condensation phenomena such as the profiles of eddy viscosity, velocities, temperature and gas concentration; vapor superheat or supercooling, liquid film thickness, interfacial shear stress, heat transfer coefficient, tube inner wall temperature, interface temperature, and vapor-gas side resistance, etc. Some of them may not be obtained from experiments.;Some aspects are suggested to be performed or incorporated into the code in the future. These include (1) verifying the turbulent liquid film model using appropriate experimental data with turbulent liquid film flow, (2) incorporating in the mist model proposed in this study or other appropriate model for the calculation of vapor bulk condensation effect, and (3) improving the numerical scheme such that it can deal with the situation when reverse flow occurs in the gaseous phase.