Liquid wall film formation in steam piping in nuclear plant

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.A numerical investigation is carried out for turbulent droplet-laden flow of saturated steam produced in a steam generator (SG) that feeds steam turbine (ST) through a long and multi-bend steam piping. The main purpose of the study is to analyze deposition of droplets that form a wall film in the piping system. Two tasks were performed: parametric study of the deposition in 90° elbows and the deposition in a more complex piping system. This system starts with outlets from the steam generator with five mouthpieces leading to a collector pipe and connecting the steam piping leading to a steam turbine. Results of the simulations show where droplets deposit and where a liquid separator should be placed to drain away the water film and to avoid droplets from entering the steam turbine. Dynamic temporal development of the film is presented showing mutual impact of gravity and entrainment by the co-flowing steam.