GPU Accelerated Large Eddy Simulation for Low Pressure Turbine Design

The mission to sustain future air superiority drives aircraft development towards operating at higher altitudes with high efficiency while also reducing overall engine weight, maintenance and cost. Of particular interest is the Low Pressure Turbine (LPT) commonly used in both commercial and military engines. The LPT is generally experiencing low Reynold number at high altitude cruise condition, which can compromise design efficiency by as much as two points compared to take off at sea level. These blade profiles introduce strong turning to provide more work for each blade row. If not designed properly, over- ambitious turning and blade load distribution could potentially lead to flow separation, unnecessary loss, and eventually lower efficiency. Of particular importance is understanding and controlling laminar to turbulent transition. Up to date, the mechanism of where and when the transition occurs is an on-going research area. LES is capable of predicting transition, but the turnaround time and computation cost associated the CPU based solvers are prohibitive in a design cycle. AeroDynamic Solutions, Inc. (ADS CFD) has developed and sold a TRL6 GPU based solver since 2018. Because of the much-shortened GPU turn-around time, the compute cost to complete each analysis is less than 50% of its traditional CPU counterpart resulting in two orders of magnitude improvement in computational efficiency. To date, significant progress has already been made. By using the LES module in the GPU solver, ADS CFD has conducted a preliminary LPT LES analysis for multiple stator vanes and compared well to experimental data. Additionally, the improved turnaround time has been demonstrated at nearly 30X, reducing what would have taken 1 month to complete to under 1 day. The focus of this proposal is to adapt the commercial ADS GPU flow solver to support next generation LPT design and analysis with fast and accurate LES simulation capabilities.á This will be the critical technology for next generation small core engines where LPT efficiency will be greatly impacted by the combination of high lift blades and laminar to turbulent transition.