Numerical Analysis of Two Phase Flow and Heat Transfer in Condensers

Abstract

Steam surface condensers are commonly used in the power generation industry and their performance significantly affects the efficiency of the power plant. Therefore, it is vital to acquire a better understanding of the complex phenomena occurring inside condensers. A general three-dimensional numerical model is developed in this study to simulate the two- phase flow and heat transfer inside full-scale industrial condensers with irregular tube bundle shapes. The Eulerian-Eulerian two-phase model is selected to simulate gas and liquid flows and the interaction between them. A porous media approach is adopted to model the presence of large number of tubes in the condenser. The effect of the turbulence on the primary phase is accounted for by solving the transport equations for turbulent kinetic energy and dissipation rate. Various types of turbulence models are evaluated to select the best model for the condenser analysis. Also, the modified k-ε and RNG k-ε models are proposed to model the flow and heat transfer in condensers by adding the corresponding terms to the transport equations of the turbulence model to account for the effects of the tube bundle and condensate droplets on the primary phase turbulence, momentum and heat transfer. The proposed model provides excellent match with the experimental data and a significant improvement over the previous models. Furthermore, the proposed numerical model is coupled with a novel swarm intelligence multi-objective optimization algorithm to evaluate the performance of the new design candidates and introduce a set of condenser designs based on various input parameters and objective functions.