Exploring Surface Roughness Effects on Spray Performance in Metal Additive Manufactured Fuel Injectors for Gas Turbine Applications

Metal additive manufacturing (AM) enables the design of complex fuel injectors for gas turbine applications. Despite its advantages, AM injectors display rougher surfaces than conventional counterparts, adversely affecting spray performance through increased droplet size and the promotion of non-circumferential sprays. Design enhancements are believed to mitigate the surface roughness limitations, thereby improving the overall performance of the injector. However, surface roughness is dependent on the AM method chosen to produce the injectors. This study provides a baseline for the correlation between surface roughness and spray performance for plain orifice fuel injectors manufactured in 316L stainless steel by Metal Binder Jetting (MBJ) and Powder Bed Fusion – Laser Beam (PBF–LB). Surface roughness and manufacturing challenges, like shrinkage, significantly impact spray characteristics in smaller channel PBF-LB and MBJ injectors, compromising their spray quality and necessitating additional post-processing steps. Larger channel injectors perform better in maintaining circumferential spray uniformity and directional stability.