Effect of Temperature on Microparticle Rebound Characteristics at Constant Impact Velocity—Part I

Abstract

Many gas turbine engines operate in harsh environments where the engines ingest solid particles. Ingested particles accelerate the deterioration of engine components and reduce the engine's service life. Understanding particle impacts on materials used in gas turbines at representative engine conditions leads to improved designs for turbomachinery operating in particle-laden environments. Coefficient of restitution (COR) is a measure of particle/wall interaction and is used to study erosion and deposition. In this study, the effect of temperature (independent of velocity) on COR was investigated. Arizona road dust (ARD) of 20–40 μm size was injected into a flow field to measure the effects of temperature and velocity on particle rebound. Target coupon materials used were Stainless Steel 304 (SS304) and Hastelloy X (HX). Tests were performed at three different temperatures: 300 K (ambient), 873 K, and 1073 K. The velocity of the flow field was held constant at 28 m/s. The impingement angle of the bulk sand on the coupon was varied from 30 deg to 80 deg for each temperature tested. The COR was found to decrease substantially from the ambient case to the 873 K and 1073 K cases. The HX material exhibits a larger decrease in COR than the SS304 material. The results are also compared to previously published literatures. The decrease in COR is believed to be due to the changes in the surface of both materials due to oxide layer formation which occurs as the target material is heated.