Experimental Investigation of Solid Particle Erosion in Successive Elbows in Gas Dominated Flows

Abstract

When a fluid containing erosive particles flows through two or more elbows mounted in series with short distances between them, the downstream elbows which are installed after the first elbow are exposed to erosion from a flow that is not fully developed, and therefore, the characteristics of erosive wear in the second elbow can be different than the first. In this work, the erosion magnitude and pattern in two standard successive vertical–horizontal and horizontal–vertical elbows are examined experimentally. Utilizing an ultrasonic technique (UT), erosion measurements are performed in gas–sand and gas–liquid–sand annular flows to investigate the effects of particle size and flowrates. A paint removal study is also performed to capture the erosion patterns in two elbows for different flow conditions. Using two clear elbows, a flow visualization is performed which shows the quality of phase distribution in the two elbows in series in annular and stratified flows. Measurements show the erosion in the second elbow for this geometry and these flow conditions are less than or in a few cases nearly equal to the first elbow. The location of maximum erosion for all the cases considered is around 45 and 65 deg from the inlet of the elbow in the first and second elbows, respectively. Two areas of high impact frequencies are identified in both elbows. One high-intensity particle impact region which is affected primarily by first impact of particles, and another pattern is formed due to rebounded particles from the first impact.