Nektar++ High Fidelity Modelling of Aircraft Engine Components

Nowadays high-order methods have reached a degree of maturity providing the industrial community with more accurate tools whilst reducing computational cost. This is of interest to the turbomachinery community, as understanding complex phenomena, such as separation, turbulent transition, incoming wakes and heat transfer, is costly with second-order solvers, but is of critical importance for design improvement. In this presentation, various jet engine components modelled using the spectral-h/p element solver Nektar++ on the Archer2 HPC system are presented. To start with, a flat plate with a pressure distribution representative of a modern fan blade is discussed. Flow solver set-up with roughness elements for turbulent transition will be shown, with the relative flow structures and modelling constraints. Moving further into the engine, a compressor stator modelled in DNS range with and without incoming turbulence is considered. The accuracy and cost of this simulation will be discussed, along with effect of the turbulent structures on the boundary layer and an experimental comparison. The last and most challenging component is the LS89 high-pressure turbine. This was modelled at low and at high suction. While the former reaches transonic range and only presents vortices convecting off the blade trailing edge, the high-suction provided significant difficulties. Due to the very low back pressure, the flow accelerates from a Mach number of 0.15 to 1.2 in a matter of cm. This causes a shock to propagate from the blade trailing edge to the outflow whilst interacting with the boundary layer and, repeatedly, with the wake.