Large Eddy Simulation of an industrial gas turbine combustor using reduced chemistry with accurate pollutant prediction

Jaravel, Thomas; Riber, Éléonore; Cuenot, Bénédicte; Bulat, Ghenadie

doi:10.1016/j.proci.2016.07.027

Cited by 75 publications

(43 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The level of this overestimate is reduced for the thickened flame model [20], however a significant overestimate was observed for the 7.5 M grid used in [21], which is similar to the results of the flamelet model. Thus, the improved comparison seen by Jaravel et al [20] is because of their very fine grid (see Table A1) which may be able to capture the strain effects with no further modelling. The 20-step mechanism was shown to over predict the ignition delay times and under predict the extinction strain rates for the thermo-chemical conditions of the SGT-100 compared to the GRI 3.0 mechanism [6] and this could be a reason for the good match seen at r ≈ 40 mm.…”

Section: E Mass Fraction Comparisonsupporting

confidence: 74%

“…However, the over prediction of the averaged temperature near r ≈ 40 mm is similar to those observed in [5]. The level of this overestimate is reduced for the thickened flame model [20], however a significant overestimate was observed for the 7.5 M grid used in [21], which is similar to the results of the flamelet model. Thus, the improved comparison seen by Jaravel et al [20] is because of their very fine grid (see Table A1) which may be able to capture the strain effects with no further modelling.…”

Section: E Mass Fraction Comparisonsupporting

confidence: 72%

“…The strained flamelets [49] or copula [41,43] methodology could be used to capture these effects. [20] are good for U at Loc. 1 and as one moves downstream, the difference among the numerical results do not change much but there is some over prediction compared to measurements in the inner shear layer region, ie., 20 ≤ r ≤ 40 mm.…”

Section: E Mass Fraction Comparisonmentioning

confidence: 96%

See 2 more Smart Citations

Large-Eddy Simulation of Reacting Flows in Industrial Gas Turbine Combustor

Langella

Chen

Swaminathan

et al. 2018

Journal of Propulsion and Power

View full text Add to dashboard Cite

The turbulent reacting flow in an industrial gas turbine combustor operating at 3 bar is computed using LES paradigm. The subgrid scale (SGS) combustion is modelled using a collection of unstrained premixed flamelets including mixture stratification.The non-premixed combustion mode is also included using a simple closure involving the scalar dissipation rate of the mixture fraction. A close attention is paid to maintain physical consistencies among sub-closure models for combustion and these consistencies are discussed on a physical basis. The importance of non-premixed mode and SGS mixture fraction fluctuations are investigated systematically. The results show that the SGS mixture fraction variance plays an important role and comparisons to measurements improve when contributions from the premixed and non-premixed modes are included. These numerical results and observations are discussed on a physical basis along with potential avenues for further improvements. a Research Associate, il246@cam.ac.uk b Research Associate, zc252@cam.ac.uk c Professor, ns341@cam.ac.uk d Engineer, suresh.sadasivuni@siemens.com 4 combustors. Thus, the ability of reacting flow CFD (Computational Fluid Dynamics) to capture these phenomena is crucial for their use in the design of next-generation combustors [2].Past studies have demonstrated that Large Eddy Simulation (LES) is suitable to capture aerodynamics of swirling flows, and the continuous increase of computing power allows application of LES-based models to practical burners [3][4][5][6][7]. Combustion requires modelling as it is a subgrid phenomenon in LES. Closures developed for the subgrid scale (SGS) reaction rate include: dynamic thickened flame model [8,9], linear eddy model [10], fractal flame-wrinkling model [11], partiallystirred reactor model [12], and Eulerian stochastic fields [13]. Another recently developed flamelet model for LES uses Scalar Dissipation Rate (SDR) closure [14,15], which is shown to be successful in RANS studies of industrial gas turbine combustors [16,17], but this approach has not been tested for LES of reacting flows in these combustors. This provides the motivation for this work.Due to large costs for experiments at realistic operating conditions of gas turbines (i.e. with optical access, high pressure, and preheated air), high quality validation data is rare [18]. One widely studied database is the set of laser-diagnostics obtained for Siemens SGT-100 combustor at 3 bar [19]. Analyses of these measurements and past LES results suggest that the combustion has flamelet-like properties despite the highly turbulent flow [5-7, 20, 21]. Flamelet models assume that the combustion time scale, τ c = s L /δ is shorter than the smallest turbulent scales (this also applies for length scales) implying that the flamelet structure is undisturbed by the turbulence. Thus, the SGS reaction rate can be calculated a priori using laminar flamelets. Hence, this methodology is also known as tabulated chemistry approach.Turbulent eddies can penetrate the flame-front di...

show abstract

Section: E Mass Fraction Comparisonsupporting

confidence: 74%

Section: E Mass Fraction Comparisonsupporting

confidence: 72%

Section: E Mass Fraction Comparisonmentioning

confidence: 96%

See 1 more Smart Citation

Large-Eddy Simulation of Reacting Flows in Industrial Gas Turbine Combustor

Langella

Chen

Swaminathan

et al. 2018

Journal of Propulsion and Power

View full text Add to dashboard Cite

show abstract

“…In the present DNS, chemistry was modelled using an ARC (Analytically Reduced Chemistry) scheme [26][27][28][29][30] adapted for ndodecane / air flames at 3.4 MPa.…”

Section: Introductionmentioning

confidence: 99%

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

Tagliante

Poinsot

Pickett

et al. 2019

Combustion and Flame

View full text Add to dashboard Cite

conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments Official URL:https://doi. ABSTRACT Keywords: ONS Lifr-off length Flame stabilization Auto-ignition Triple flame Diesel combustionThis work presents an analysis of the stabilization of diffusion flames created by the injection of fuel into hot air, as found in Diesel engines. lt is based on experimental observations and uses a dedicated Direct Numerical Simulation ( ONS) approach to construct a numerical setup, which reproduces the igni tion features obtained experimentally. The resulting ONS data are then used to classify and analyze the events that allow the flame to stabilize at a certain Lift-Off Length (LOL) from the fuel injector. Both ONS and experiments reveal that this stabilization is intermittent: flame elements first auto-ignite before being convected downstream until another sudden auto-ignition event occurs closer to the fuel injec tor. The flame topologies associated to such events are discussed in detail using the ONS results, and a conceptual mode( summarizing the observation made is proposed. Results show that the main flame sta bilization mechanism is auto-ignition. However, multiple reaction zone topologies, such as triple flames , are also observed at the periphery of the fuel jet helping the flame to stabilize by filling high-temperature burnt gases reservoirs localized at the periphery, which trigger auto-ignitions.

show abstract

“…High fidelity simulations of reactive turbulent flows using finite-rate chemistry is a promising tool for furthering the understanding of physical pro-cesses such as ignition, extinction, flame stabilization, pollutant formations, etc. [14,19,38,45], which are of great scientific and engineering importance but are also difficult to be accurately captured by lower-order models [15,37,41] Calculations of such kind are inherently expensive due to the large number of species and reactions involved. Consequently, the efficiency of the numerical methods and their implementations becomes critical given the high overall cost at stake.…”

Section: Introductionmentioning

confidence: 99%

Efficient time stepping for reactive turbulent simulations with stiff chemistry

Peter

Ihme

2018

2018 AIAA Aerospace Sciences Meeting

View full text Add to dashboard Cite

A combination of a steady-state preserving operator splitting method and a semi-implicit integration scheme is proposed for efficient time stepping in simulations of unsteady reacting flows, such as turbulent flames, using detailed chemical kinetic mechanisms. The operator splitting is based on the Simpler balanced splitting method, which is constructed with improved stability properties and reduced computational cost. The method is shown to be capable of stable and accurate prediction of ignition and extinction for reaction-diffusion systems near critical conditions. The ROK4E scheme is designed for semi-implicit integration of spatially independent chemically reacting systems. Being a Rosenbrock-Krylov method, ROK4E utilizes the low-rank approximation of the Jacobian to reduce the cost for integrating the system of ODEs that have relative few stiff components. The efficiency of the scheme is further improved via the careful choice of coefficients to require three right-hand-side evaluations over four stages. Combing these two methods, efficient calculation is achieved for large-scale parallel simulations of turbulent flames.

show abstract

Large Eddy Simulation of an industrial gas turbine combustor using reduced chemistry with accurate pollutant prediction

Cited by 75 publications

References 19 publications

Large-Eddy Simulation of Reacting Flows in Industrial Gas Turbine Combustor

Large-Eddy Simulation of Reacting Flows in Industrial Gas Turbine Combustor

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

Efficient time stepping for reactive turbulent simulations with stiff chemistry

Contact Info

Product

Resources

About