Numerical investigation of condensation in inclined tube air-cooled condensers

Abstract

Air-cooled condensers (ACC) have the potential to drastically reduce water consumption in power plants using a steam Rankine cycle operating; however, there are very few comprehensive models to simultaneously describe the heat and mass transfer effects for both the air and steam domains. This paper presents a coupled model for laminar film condensation and air-side convective cooling for an inclined air cooled condenser tube. The air-side fluid flow is modeled using ANSYS Fluent. A Nusselt thin film analysis is then used to describe the film thickness in the upper region of the tube interior with a pool condensation model used to define the axial flow in the lower region. The commonly used isothermal boundary condition is relaxed by applying the heat transfer at the tube surface on the air-side to the inside tube surface during the film analysis to investigate the impact on the local film thickness and the overall heat transfer coefficient of the condenser. The results are related to the heat transfer on both staggered and inline tube configurations.