Effects of Subgrid Scale Modeling on the Deterministic and Stochastic Turbulent Energetic Distribution in Large-Eddy Simulations of a High-Pressure Turbine Stage

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Dimitrios Papadogiannis ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Gaofeng Wang ◽  
Stéphane Moreau
Keyword(s):  
High Pressure ◽  
Decomposition Analysis ◽  
Large Eddy Simulations ◽  
Reference Frequency ◽  
Subgrid Scale ◽  
High Pressure Turbine ◽  
Pressure Profiles ◽  
Radial Profiles ◽  
Large Eddy ◽  
Flow Features

This study focuses on the engine-representative MT1 transonic high-pressure turbine. Simulated by use of wall-modeled large-eddy simulations (LES) with three different subgrid scale (SGS) closures, mean pressure profiles across the blades as well as mean radial profiles at the rotor exit are found to be in good agreement with experimental data with only local differences between models. Unsteady flow features, inherently present in LES, are however affected by SGS modeling. This is evidenced by the relative energetic content of the deterministic to stochastic turbulent contributions evaluated, thanks to the triple decomposition analysis of the simulations. Origins of such differences are found to impact the entire radial distribution of the flow and activity, with deterministic and chaotic contributions distributed differently depending on the SGS model and reference frequency used to extract the deterministic signal. Such flow responses can be attributed to the different SGS capacities to satisfy basic turbulent flow features that translate in different dissipative and turbulent diffusive contributions of the three SGS models.

Evaluation of the Capacity of RANS/URANS/LES in Predicting the Performance of a High-Pressure Turbine: Effect of Load and Off Design Condition

2020 ◽  
Author(s):  
Jérôme Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Nicolas Odier ◽  
Kevin Leroy ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Law Of The Wall ◽  
Eddy Simulation ◽  
Radial Profiles ◽  
Large Eddy ◽  
Design Perspective ◽  
Good Agreement ◽  
Do So

Abstract This paper aims at addressing design issues of turbomachinery configurations by use of Large-Eddy Simulation (LES). To do so, a research state-of-the-art high-pressure turbine stage, without technological details and for which experimental data are available, is computed with the three methods: i.e. RANS, URANS and LES. Starting from the nominal operating design, a database is acquired varying the design space (three Zweifel numbers), load (three pressure rates) and rotation speed (three reduced speeds). The analysis of the database is carried out incrementally from a design perspective. Numerical results are systematically compared to experimental ones. Main conclusions are threefold: 1/ Calibrated RANS provides excellent results at the nominal operating point but lacks of accuracy at off design conditions. Only unsteady methods (both URANS and LES) allow a good agreement with experiment along the whole database. 2/ Although very good on the overall performances, LES provides radial profiles and 2D maps leaving room for improvement in comparison with the URANS predictions. 3/ LES and standard law-of-the-wall is validated against experiments in a high-pressure turbine without technological details but still representative of a realistic and recent industrial design. From an aero design point, this paper shows the interest in using URANS for off design conditions. It also represents a milestone for LES that had to be passed before addressing more complex issues which URANS hardly addresses.

Advanced Statistical Analysis Estimating the Heat Load Issued by Hot Streaks and Turbulence on a High-Pressure Vane in the Context of Adiabatic Large Eddy Simulations

2017 ◽  
Author(s):  
Martin Thomas ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Charlie Koupper
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
Guide Vane ◽  
Large Eddy Simulations ◽  
High Pressure Turbine ◽  
Substantial Impact ◽  
Lean Combustion ◽  
Large Eddy ◽  
Inlet Conditions ◽  
The Impact

The next generation of lean combustion engines promises to further decrease environmental impact and cost of air traffic. Compared to the currently employed Rich Quench Lean (RQL) concept, the flow field at the exit of a lean combustion chamber is characterized by stronger variations of velocity as well as temperature and higher levels of turbulence. These specific features may have a substantial impact on the aerothermal performance of the high-pressure turbine and thereby on the efficiency of the entire engine. Indeed, high levels of turbulence in the Nozzle Guide Vane (NGV) passages locally impact the heat flux and result in globally over dimensioned cooling systems of the NGV. In this study, Large Eddy Simulations (LES) are performed on an engine representative lean combustion simulator geometry to investigate the evolution of turbulence and the migration of hot streaks through the high-pressure turbine. To investigate the impact of non-uniform stator inlet conditions on the estimated thermal stress on the NGVs, adiabatic LES predictions of the lean combustor NGV FACTOR configuration are analyzed through the use of high statistical moments of temperature and two point statistics for the assessment of turbulent quantities. Relations between temperature statistical features and turbulence are evidenced on planes through the NGV passage pointing to the role of mixing and large scale features along with marked wall temperatures that locally can largely differ from obtained mean values.

Subgrid-scale models for large-eddy simulations of compressible wall bounded flows

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1340-1350 ◽  
Author(s):  
E. Lenormand ◽  
P. Sagaut ◽  
L. Ta Phuoc ◽  
P. Comte
Keyword(s):  
Large Eddy Simulations ◽  
Subgrid Scale ◽  
Scale Models ◽  
Large Eddy ◽  
Wall Bounded Flows

scholarly journals Statistical ensemble of large-eddy simulations

2002 ◽  
Vol 455 ◽  
pp. 195-212 ◽  
Author(s):  
DANIELE CARATI ◽  
MICHAEL M. ROGERS ◽  
ALAN A. WRAY
Keyword(s):  
Large Scale ◽  
Isotropic Turbulence ◽  
Velocity Fields ◽  
Large Eddy Simulations ◽  
Statistical Ensemble ◽  
Model Parameters ◽  
Spatial Averaging ◽  
Subgrid Scale ◽  
Large Eddy ◽  
New Models

A statistical ensemble of large-eddy simulations (LES) is run simultaneously for the same flow. The information provided by the different large-scale velocity fields is used in an ensemble-averaged version of the dynamic model. This produces local model parameters that only depend on the statistical properties of the flow. An important property of the ensemble-averaged dynamic procedure is that it does not require any spatial averaging and can thus be used in fully inhomogeneous flows. Also, the ensemble of LES provides statistics of the large-scale velocity that can be used for building new models for the subgrid-scale stress tensor. The ensemble-averaged dynamic procedure has been implemented with various models for three flows: decaying isotropic turbulence, forced isotropic turbulence, and the time-developing plane wake. It is found that the results are almost independent of the number of LES in the statistical ensemble provided that the ensemble contains at least 16 realizations.

Subgrid scale variance and dissipation of a scalar field in large eddy simulations

2001 ◽  
Vol 13 (6) ◽  
pp. 1748-1754 ◽  
Author(s):  
C. Jiménez ◽  
F. Ducros ◽  
B. Cuenot ◽  
B. Bédat
Keyword(s):  
Scalar Field ◽  
Large Eddy Simulations ◽  
Subgrid Scale ◽  
Large Eddy
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