Experimental Investigation of Water Droplet Erosion on Metallic and Non-Metallic Materials

Abstract

Abstract Water droplet erosion (WDE) is a complex phenomenon that has been investigated for nearly a century. This form of erosion affects a wide range of energy industries from steam turbines and natural gas pipelines to wind turbine blades. The moving droplets impacting at a high relative speed create a high surge in surface pressure on the impacted material and damage the surface. The damage removes materials and can compromise strength for steam turbines and pipelines or affect the lift and drag forces on wind turbine blades. Research on WDE has been ongoing for decades with a majority of the reported results focused on metallic material testing and qualitative analysis comparing methodologies or surface conditions. The ongoing research at The University of Tulsa is conducting experiments with a variety of materials while exposed to an environment where water droplet erosion occurs. Impact velocity and droplet sizes are controlled within the facility and ongoing research with particle image velocimetry (PIV) is in use to characterize the falling droplets. Stainless steel 316, Aluminum 6061, and a variety of non-metallic materials are tested for a variety of conditions. The mass of each specimen is tracked and recorded at set intervals to determine the erosion ratio and erosion rate. Various other factors such as flowrate and rotational velocity are determined before testing as well as the percentage of droplets which impact the surface is determined with the use of a highspeed camera. Scanning electron microscopy (SEM) is also utilized to examine the material’s surfaces before and after testing to investigate the severity of erosion by water droplets. One impact velocity and one impact angle are set for all tested materials. These data points will be the starting point for future tests and modeling work to predict water droplet erosion based on simple factors.