Ultra-Compact Traverse System for Transonic Annular Cascade

In this study we present detailed aerodynamic and thermal field measurements downstream of an annular cascade of fully-cooled nozzle guide vanes (NGVs). The experiments were conducted in the Engine Component AeroThermal (ECAT) facility at the University of Oxford, at engine-matched conditions of Reynolds number and Mach number, and high turbulence intensity. The experimental data are unusually high-fidelity and allow for detailed comparison with modern computational fluids dynamics (CFD) methods. We compare the experimental data to simulations of fully-featured geometry (resolved internal geometry and film cooling holes). We analyze distributions of whirl angle, kinetic energy loss, and non-dimensional temperature at three axial planes downstream of the NGVs. The aerodynamic and thermal wakes are also characterized in terms of their spreading and decay rates. The analysis is deepened with detailed comparison to a previous data-set for a different design of heavily-cooled NGV. The analysis a useful reference point for assessing the accuracy of the current state-of-the-art numerical methods used in the engine design process.

Aerodynamic and Thermal Field Development of Cooled Transonic HP NGV

Amend,

Lubbock,

Ornano

et al. 2023

Comparison of Eddy Viscosity Models for High Turbulence Nozzle Guide Vane Flows

Amend,

Povey

2024

In this paper we investigate the performance of eddy viscosity turbulence models for high-pressure nozzle guide vane (NGV) flows with engine-realistic turbulence. Using metrics such as integrated kinetic energy (KE) loss and mixing rate, we compare simulation results using turbulence models with high-fidelity experimental data from fully-cooled NGVs, operating at engine-matched conditions of Reynolds number and Mach. For the widely-used k–ω shear stress transport (SST) model, the aerodynamic and thermal wakes of the NGVs were undermixed, due to the artificial suppression of the incoming turbulence. We compare simulation results with those using other common turbulence models including the standard k–ω, baseline k–ω, Spalart–Allmaras, and baseline explicit algebraic Reynolds stress model. Alternative turbulence models formulations are explored, with an emphasis on modifications to the implementation of the shear stress limiter. We also investigate the sensitivity of models to the specified inlet turbulence intensity. We demonstrate that predictions of integrated KE loss, as well as the decay trends of the aerodynamic and thermal wakes are a closer match to experimental data for the baseline algebraic Reynolds stress model than for other turbulence models in more common use for NGV predictions.

Impact of Lean-Burn Combustor Flow on Nozzle Guide Vane Performance

Amend,

Chowdhury,

Povey

2024

In this paper we investigate the impact of lean-burn-representative swirl and temperature distortion on the aerothermal performance of fully-cooled high-pressure nozzle guide vanes (NGV) from a modern aero-engine. Experiments were carried out in the Engine Component AeroThermal (ECAT) facility at the University of Oxford. This is a fully-annular warm-flow engine-parts facility, designed to operate at engine-representative conditions of Reynolds and Mach number. Inlet profiles of swirl, turbulence, and non-dimensional total temperature were generated using a non-reacting combustor simulator. The NGV outlet flow was experimentally characterized at three downstream planes in experiments with and without lean-burn-representative inlet conditions. Area-survey measurements included distributions of whirl angle, kinetic energy (KE) loss, and non-dimensional total temperature. Experimental data is compared to CFD simulations. Fully-featured NGV geometry (including film cooling holes and internal passages) was used, to account for internal cooling flow redistribution resulting from altered external loading. We show that lean-burn inlet conditions result in significant surface flow redistribution, relatively high levels of residual swirl in the downstream flow, and a small increase of integrated KE loss.