Comparison of LES and RANS predictions with experimental results of the fan of a turbofan

Abstract

This paper aims at validating LES capability if applied to an actual turbofan configuration at nominal regime, if compared to RANS and experimental measurements. For assessment, averaged radial profiles are compared in 3 axial planes-before the stage, between the rotor blade and stator vanes, and downstream of the stator. RANS and LES results are in very good agreement, but found to be shifted compared to the measurements and for some quantities. An analysis of the unsteady axial velocity is then proposed, investigating root-mean square of axial velocity. Tip-leakage, as well as two boundary layer transitions are evidenced in the rotor. An estimation of the integral turbulent timescale is finally proposed in the whole domain, using autocorrelation of the axial velocity. Suctionside horseshoe vortices are found to be very coherent, as well as the stator corner vortices. Regions of large timescale are moreover evidenced between rotor and stator wakes.

Towards the Large-Eddy Simulation of a full engine: Integration of a 360 azimuthal degrees fan, compressor and combustion chamber. Part I: Methodology and initialisation

“…All meshes are unstructured and solely made of tetrahedral elements. The FAN + OGV mesh is similar to the "M1" mesh computed by Odier et al (2017) with…”

“…However, being a rather new demonstrator, related research is scarce. The associated available literature found can be grouped in 4 categories: performance cycle studies using 0D approximations (Pilet et al, 2011;López de Vega et al, 2019), acoustics and liners research (Berton, 2016;Brown and Sutliff, 2018;Nark et al, 2018;Sutliff et al, 2019;Nagai et al, 2019) including combustion noise (Boyle et al, 2018(Boyle et al, , 2020, experimental and RANS campaigns at wind-milling conditions (Dufour et al, 2015;García Rosa et al, 2015;Dufour and Thollet, 2016) and experimental as well as LES investigations of the flow around the fan and the Outlet-Guide Vanes (OGV) at the nominal operating point (Odier et al, 2017(Odier et al, , 2018.…”

Wall-Modeled Large-Eddy Simulations of a Multistage High-Pressure Compressor

“…It is also a massively parallel solver, with a demonstrated efficient scalability [13]. TurboAVBP has already been applied to fan stages [28,37], a single compressor stage [55], a single turbine stage [40,39,56] and a combustion chamber coupled to a turbine stage [11]. In these cases, comparisons with experimental and (U)RANS data highlighted the beneficial contribution of the LES solver even in a wall-modeled context.…”

LES-based simulation of the time-resolved flow for rotor-stator interactions in axial fan stages

“…Latest contributions in the open literature to LES modeling of multistage turbomachinery include the simulation of gas turbine compressors at off-design conditions (McMullan and Page, 2012), high-pressure turbine stages with blade/vane rescaling (Papadogiannis et al , 2016; Wang et al , 2014), high-pressure turbine blades (Zauner et al , 2017) or fan modeling in a turbofan (Odier et al , 2017). In the case of tip-leakage modeling, the grid requirements are dramatically increased, up to 10 7 to 2⋅ 10 7 cells for wall-modeled computations and even 10 8 to 2⋅ 10 8 cells when wall-resolving meshes are used.…”