Analysis of the impact of droplets onto water films in drift eliminators

Abstract

Water droplets emitted from cooling towers must be prevented for several reasons, human health hazards are the most important ones. The generation and control of these droplets are the main tasks for drift eliminators: devices installed inside mechanical draft cooling towers useful in order to prevent water droplets, originated by the crossflow between air and water inside the tower, from being released into the environment. This is the phenomenon called ‘drift’. In this paper, the operating conditions of a type of drift eliminator placed in a cooling tower are studied. This work is focused on the numerical and experimental characterization of the multiphase flow taking place when water droplets, drifted by the airstream, impact on the water film formed over the drift eliminators plates. The problem of these drop impacts has been studied throughout an experimental installation and a numerical model has been developed throughout the ANSYS software and several VOF multiphase flow simulations have been carried out showing a good agreement with experimental data