Direct Numerical Simulation of Additively and Conventionally Manufactured Internal Turbine Cooling Passages*

Metal additive manufacturing technology based on Powder Bed Fusion (PBF) is revolutionizing engineering practice and system performance in many venues including gas turbine systems. In order for the community to fully harness the opportunity that PBF offers in this context, we need to mature flow/thermal design tools to accommodate the very complex “roughness field” that invariably characterizes these engineered flow passages. Our team is executing a combined CFD+EFD program that includes Direct Numerical Simulation (DNS) of the turbulent flow in these passages to calibrate reduced order Reynolds Averaged Navier-Stokes (RANS) CFD based on Distributed Element Roughness Modeling (DERM). Here we will present our DNS results for PBF manufactured rectangular channels. These geometries have been obtained and meshed for DNS directly from CT scan and Optical Profilometry observations. Also they have been/are being tested at engine scale and large scale for flow and heat transfer performance. We compare the PBF channel DNS results with these measurements, and with smooth channel DNS and measurements.