Droplet Diameter Measurements for the Prediction of Liquid Droplet Impingement Erosion

The characteristics of liquid droplet diameter are investigated for the prediction of liquid droplet impingement erosion (LDI) occurring in a power plant. Since the main factors causing LDI are fluid-related factors such as droplet velocity and diameter, it is possible to predict the location of LDI attack if the local flow conditions such as velocity, wetness and droplet diameter are clarified. These local flow conditions except for droplet diameter can be obtained by calculation. Thus, we conducted steam experiment to measure the droplet diameter in the steam flow and clarify the characteristics of the droplet and the correlation between droplet diameter and another state quantities of the steam. As a result, we found that a distribution of the droplet diameter could be approximated by gamma distribution, which is a general form of the exponential distribution. To obtain the correlation between the diameter and the state quantities, we considered the change of the heat energy in addition to the surface tension and shear force, and we checked the correlation between the state quantites of steam and droplet diameter. A good correlation was found between these quantities and the droplet diameter, and the proposed approximate formula for the diameter was obtained.