Fundamentals of fluid motion in erosion by solid particle impact

Abstract Judging from the extensive literature on the subject, the phenomenon of material erosion by solid-particle impact continues to challenge both practitioners and theoreticians with very complex problems. Although the importance of fluid motion to this form of wear was recognized in early works, many researchers continue to interpret and attempt to understand particle impact erosion almost exclusively in terms of the material properties involved. Little attention has been given to clarifying the influence of fluid motion, especially in the turbulent flow regime. A review of some relevant issues is presented here. It starts with an exposition of the general problem and the need for better understanding. The discussion of experimental techniques is followed by various fundamental considerations relating to the motion of solid particles conditioned by the presence of a carrier fluid, neighboring particles, and a constraining solid surface. Of the experimental techniques used in erosion studies, nonintrusive optical methodologies are the most promising for measuring particle and fluid-phase velocities simultaneously near a surface. Numerical models for calculating particle-laden flows and their application to predict erosion in practical engineering flow configurations are briefly discussed. Emphasis is placed on uncovering areas of inadequate fundamental understanding of fluid mechanics phenomena that significantly affect erosion by solid particle impact.