The Influence of Injector Geometry and Carrier Gas Flow Rate on Spray Pattern

Abstract

Abstract The performance (particle velocity and velocity distribution) of a typical injector, and the resulting particle spray pattern for metallic (NiCrAlY) and ceramic (ZrO2) particles are examined as a function of carrier gas flow rate and the effect of varying the geometry immediately upstream of the injector. Injector performance is also examined for a 1:1 mixture of ceramic and metallic particles such as is used in the spraying of functionally graded materials. The upstream geometries tested included a 90° "tee," a 90° elbow, and a straight entrance. The elbow geometry was tested in both "up" and "down" orientation to determine the influence of gravity. The upstream geometry can alter the average particle injection velocity by 10-15% influencing both the spray pattern trajectory and width.