Large Eddy Simulation for Turbines: Methodologies, Cost and Future Outlooks

Tyacke, James; Tucker, Paul G.; Jefferson-Loveday, Richard; Vadlamani, Nagabhushana Rao; Watson, Robert P.; Naqavi, Iftekhar Z.; Yang, Xiaoyu

doi:10.1115/1.4025589

Cited by 38 publications

(25 citation statements)

References 42 publications

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“…The small differences between these contours with those in Figures 5 and 6, belonging to the same simulation settings but without SGS model (Set-B), reveal the fact that for the FV-based implicitly-filtered LES carried out using nominally second-order accurate schemes, see Section II C, the numerical errors play the dominant role compared to the errors induced by the adopted SGS model. This is consistent with the results in [11,13,41,43]. Despite this, the errors in different quantities can be slightly affected by SGS modeling.…”

Section: E Effect Of Sgs Modelingsupporting

confidence: 91%

Effect of grid resolution on large eddy simulation of wall-bounded turbulence

Rezaeiravesh

Liefvendahl

2018

Physics of Fluids

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The effect of grid resolution on large eddy simulation (LES) of wall-bounded turbulent flow is investigated. A channel flow simulation campaign involving systematic variation of the streamwise (∆x) and spanwise (∆z) grid resolution is used for this purpose. The main friction-velocity based Reynolds number investigated is 300. Near the walls, the grid cell size is determined by the frictional scaling, ∆x + and ∆z + , and strongly anisotropic cells, with first ∆y + ∼ 1, thus aiming for wallresolving LES. Results are compared to direct numerical simulations (DNS) and several quality measures are investigated, including the error in the predicted mean friction velocity and the error in cross-channel profiles of flow statistics. To reduce the total number of channel flow simulations, techniques from the framework of uncertainty quantification (UQ) are employed. In particular, generalized polynomial chaos expansion (gPCE) is used to create meta models for the errors over the allowed parameter ranges. The differing behavior of the different quality measures is demonstrated and analyzed. It is shown that friction velocity, and profiles of velocity and the Reynolds stress tensor, are most sensitive to ∆z + , while the error in the turbulent kinetic energy is mostly influenced by ∆x + . Recommendations for grid resolution requirements are given, together with quantification of the resulting predictive accuracy. The sensitivity of the results to subgrid-scale (SGS) model and varying Reynolds number is also investigated. All simulations are carried out with second-order accurate finite-volume based solver OpenFOAM. It is shown, the choice of numerical scheme for the convective term significantly influences the error portraits. It is emphasized that the proposed methodology, involving gPCE, can be applied to other modeling approaches, i.e. other numerical methods and choice of SGS model.

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Section: E Effect Of Sgs Modelingsupporting

confidence: 91%

Effect of grid resolution on large eddy simulation of wall-bounded turbulence

Rezaeiravesh

Liefvendahl

2018

Physics of Fluids

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“…To guide the aerodynamicist through the simulation process, a system based around flow taxonomies is proposed in the framework of ZDES. This suggestion is also highly supported by Tyacke et al [18].…”

Section: (C) Zonal Detached Eddy Simulationsupporting

confidence: 71%

“…The authors' position is now increasingly shared by other teams [14,17]. As an example, in the framework of turbomachinery applications, Tyacke et al [18] state that 'the expectation of producing a single modelling strategy that will work effectively and reliably for all engine zones is unrealistic'! The ZDES approach presented in §2c enables one to combine the best features of both zonal and non-zonal approaches in a unified framework in order to provide an efficient RANS-LES methodology for most technical applications.…”

Section: A Glimpse At Advanced Simulations Of Unsteady Turbulent Flowmentioning

confidence: 99%

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation

Deck

Gand

Brunet

et al. 2014

Phil. Trans. R. Soc. A.

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This paper provides an up-to-date survey of the use of zonal detached eddy simulations (ZDES) for unsteady civil aircraft applications as a reflection on the stakes and perspectives of the use of hybrid methods in the framework of industrial aerodynamics. The issue of zonal or non-zonal treatment of turbulent flows for engineering applications is discussed. The ZDES method used in this article and based on a fluid problem-dependent zonalization is briefly presented. Some recent landmark achievements for conditions all over the flight envelope are presented, including low-speed (aeroacoustics of high-lift devices and landing gear), cruising (engine-airframe interactions), propulsive jets and off-design (transonic buffet and dive manoeuvres) applications. The implications of such results and remaining challenges in a more global framework are further discussed.

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Section: Introductionmentioning

confidence: 96%

“…The complexity of the geometry and the nature of the flow (wall bounded, high Reynolds number) impose the use of turbulence modelling to represent the cascade of energy (the so-called Reynolds-averaged Navier-Stokes (RANS) approach). However, as reported in the literature [3,4], there is some evidence that such turbulence models are not accurate for complex flows as encountered in turbomachinery.With increasing computing power, large eddy simulation (LES) appears as an alternative to classical RANS methods. LES has already been successfully applied to a wide range of turbomachinery problems, such as off-design operating conditions [5,6], secondary flows [7,8], heat transfer [9][10][11][12] and aero-acoustics [13].…”

mentioning

confidence: 96%

Large eddy simulation of flows in industrial compressors: a path from 2015 to 2035

Gourdain

Sicot

Duchaine

et al. 2014

Phil. Trans. R. Soc. A.

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One contribution of 13 to a Theme Issue 'Aerodynamics, computers and the environment' . A better understanding of turbulent unsteady flows is a necessary step towards a breakthrough in the design of modern compressors. Owing to high Reynolds numbers and very complex geometry, the flow that develops in such industrial machines is extremely hard to predict. At this time, the most popular method to simulate these flows is still based on a Reynoldsaveraged Navier-Stokes approach. However, there is some evidence that this formalism is not accurate for these components, especially when a description of time-dependent turbulent flows is desired. With the increase in computing power, large eddy simulation (LES) emerges as a promising technique to improve both knowledge of complex physics and reliability of flow solver predictions. The objective of the paper is thus to give an overview of the current status of LES for industrial compressor flows as well as to propose future research axes regarding the use of LES for compressor design. While the use of wallresolved LES for industrial multistage compressors at realistic Reynolds number should not be ready before 2035, some possibilities exist to reduce the cost of LES, such as wall modelling and the adaptation of the phase-lag condition. This paper also points out the necessity to combine LES to techniques able to tackle complex geometries. Indeed LES alone, i.e. without prior knowledge of such flows for grid construction or the prohibitive yet ideal use of fully homogeneous meshes to predict compressor flows, is quite limited today. IntroductionThe aeronautic industry faces a formidable challenge by targeting in 2050 a reduction of CO 2 and NO x 2014 The Author(s) Published by the Royal Society. All rights reserved. emissions by 75% and 90% per kilometre and per passenger, respectively (compared to the 2000 level). Ultra-high bypass ratio (BR > 20) turbofan and ultra-high overall pressure ratio (OPR > 70) core engines have the potential for such significant reductions in fuel burn. However, after many years of optimization, the design of ever more efficient gas turbines now requires understanding of the complex unsteady flow appearing within each individual component and in an integrated fashion. Among all components, the compressor remains a critical part of a gas turbine, especially regarding its efficiency and stability. Owing to the adverse pressure gradients, compressors are naturally subjected to unstable flows such as surge and rotating stall [1], which can potentially lead to mechanical failure. These aerodynamic instabilities impose serious constraints on the design (the so-called 'surge margin') and thus on performance. In this context, maximizing the efficiency of compressors remains particularly complex and the improvement of the compressor robustness and performance thus requires good understanding of the flow physics.Complementary to experimental investigations, the numerical simulation of flows, commonly referred to as computational fluid dynamics (CFD), is...

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Large Eddy Simulation for Turbines: Methodologies, Cost and Future Outlooks

Cited by 38 publications

References 42 publications

Effect of grid resolution on large eddy simulation of wall-bounded turbulence

Effect of grid resolution on large eddy simulation of wall-bounded turbulence

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation

Large eddy simulation of flows in industrial compressors: a path from 2015 to 2035

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