An Analysis of the Bi-modal Size Distribution of the Coarse Droplets in a Steam Turbine

Abstract

The atomization of liquid is a widely studied problem in the field of aerosol research. Over the past year, research at CTU has focused on the formation of coarse droplets in a wind tunnel which simulates the conditions present in a steam turbine. An analysis of the droplets formed in the wind tunnel indicates, for the majority of the measurements, the bi-modal droplets size distribution. The aim of this paper is to suggest a simplified explanation of this bi-modal distribution. The CFD simulation of the flow in the vicinity of the liquid film break up was used to determine the relative velocity between the formed droplet and the bulk flow. The preliminary explanation of the bi-modal distribution is based on the first droplets mode corelating with the formation in the bulk flow and the second mode correlating with the droplets formed in the blade’s wake.