The Influence of High Surface Roughness on the Aerodynamic Performance of Additive Manufactured Compressor Blade

Additive manufacturing frequently yields components with relatively high surface roughness when compared to their subtractive manufacturing counterparts. This elevated surface roughness can have a profound impact on compressor performance by perturbing the boundary layer. Consequently, a comprehensive investigation into the influence of surface roughness on the aerodynamic performance of additively manufactured compressor blades becomes imperative. In this study, a linear cascade experiment is conducted to examine the effects of elevated surface roughness within a fully rough regime on compressor blades produced through additive manufacturing. Sandpaper is employed as a surrogate for surface roughness. Deviations and total pressure loss are assessed at the midspan using a 5-hole probe. Furthermore, numerical analysis is conducted using two models to simulate the ramifications of surface roughness via the commercial software, ANSYS CFX. In the linear cascade experiments, surface roughness on compressor blades results in a 27.9% increase in mass-averaged deviation at midspan and a 98.2% increase in mass-averaged total pressure loss at midspan. Numerical analysis results exhibit reasonable agreement regarding the increase in pressure loss coefficient due to surface roughness, albeit with a larger deviation than the experimental result. The results from both the experiment and numerical analysis conclusively establish that high surface roughness on additively manufactured compressor blades substantially elevates deviations and pressure loss.