Large Eddy Simulation of an Open Fan Blade at Full-Scale Reynolds Number

Abstract

Large-scale commercial turbofan designs are typically evaluated early in the technology maturation phase through subscale rig tests, while evaluations at full scale can only feasibly occur much later in a given engine development program. Therefore, how Reynolds number (Re) affects the aerodynamic and acoustic performance is of key interest while multiple candidate fan designs are still being evaluated and refined early in the program, and often tested scaled down to lower Re relative to the end application. To confidently evaluate full-scale Re performance, however, large-scale physical testing is traditionally required because the high-fidelity simulations needed to capture the complex physics associated with high Re turbulent flows, such as wall-resolved large eddy simulations (LES), are challenging due to the extremely high computational cost. In this article, we present wall-resolved LES of an open fan blade at full scale for a highly loaded design operating at a condition representative of takeoff for acoustic considerations. The simulations are at high order (up to sixth) and have been performed using the unstructured LES solver, GENESIS. These simulations extend prior research to allow for a study of practically relevant flight scale Re, for which wall-resolved LES is now possible with computing capability available at the Oak Ridge Leadership Computing Facility (OLCF) exascale supercomputer, Frontier. The observed effects at flight scale Reynolds number of the flow physics on the blade and into the wake are presented in specific regions of interest that can affect the overall blade aeroacoustic design.