A Non-Adiabatic Flamelet Progress–Variable Approach for LES of Turbulent Premixed Flames

Cecere, D.; Giacomazzi, E.; Picchia, F.R.; Arcidiacono, N.; Donato, Filippo; Verzicco, Roberto

doi:10.1007/s10494-010-9319-7

Cited by 15 publications

(7 citation statements)

References 32 publications

(54 reference statements)

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“…For non-adiabatic conditions, several flamelets at different enthalpy levels are determined by the solution of burner stabilized one-dimensional laminar premixed flame simulations with varying mass flow rate [3, 37, 38]. The flamelets are parametrized in terms of the normalized enthalpy scalar i as defined in Section 2.1.3.…”

Section: Modeling Approachmentioning

confidence: 99%

The Effect of Partial Premixing and Heat Loss on the Reacting Flow Field Prediction of a Swirl Stabilized Gas Turbine Model Combustor

Gövert

Mira

Kok

et al. 2017

Flow Turbulence Combust

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This work addresses the prediction of the reacting flow field in a swirl stabilized gas turbine model combustor using large-eddy simulation. The modeling of the combustion chemistry is based on laminar premixed flamelets and the effect of turbulence-chemistry interaction is considered by a presumed shape probability density function. The prediction capabilities of the presented combustion model for perfectly premixed and partially premixed conditions are demonstrated. The effect of partial premixing for the prediction of the reacting flow field is assessed by comparison of a perfectly premixed and partially premixed simulation. Even though significant mixture fraction fluctuations are observed, only small impact of the non-perfect premixing is found on the flow field and flame dynamics. Subsequently, the effect of heat loss to the walls is assessed assuming perfectly premixing. The adiabatic baseline case is compared to heat loss simulations with adiabatic and non-adiabatic chemistry tabulation. The results highlight the importance of considering the effect of heat loss on the chemical kinetics for an accurate prediction of the flow features. Both heat loss simulations significantly improve the temperature prediction, but the non-adiabatic chemistry tabulation is required to accurately capture the chemical composition in the reacting layers.

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Section: Modeling Approachmentioning

confidence: 99%

The Effect of Partial Premixing and Heat Loss on the Reacting Flow Field Prediction of a Swirl Stabilized Gas Turbine Model Combustor

Gövert

Mira

Kok

et al. 2017

Flow Turbulence Combust

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show abstract

“…For such cases, several flamelets at different enthalpy levels are required in order to accurately describe the combustion process [34]. Two different approaches can be chosen for the creation of the flamelets at reduced enthalpy: either the inlet temperature is reduced using a freely propagating flame configuration or the conductive heat losses at the burner inlet are increased by a reduced mass flow rate using a burner stabilized calculation.…”

Section: Heat Loss Inclusionmentioning

confidence: 99%

Turbulent combustion modelling of a confined premixed jet flame including heat loss effects using tabulated chemistry

et al. 2015

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The present work addresses the coupling of a flamelet database, to a low-Mach approximation of the NavierStokes equations using scalar controlling variables. The model is characterized by the chemistry tabulation based on laminar premixed flamelets in combination with an optimal choice of the reaction progress variable, which is determined based on the computational singular perturbation (CSP) method. The formulation of the model focuses on turbulent premixed flames taking into account the effect of heat losses, but it is easily extended to partially premixed and non-premixed regimes. The model is designed for applications in both, Reynolds-averaged Navier-Stokes (RANS) as well as large-eddy simulations (LES) and results for the two methods are compared. A priori analysis of the database is presented to demonstrate the influence of the reaction progress definition and the chemistry tabulation is validated against a one-dimensional premixed laminar flame. The validation of the turbulent case is performed using a turbulent premixed confined jet flame subject to strong heat losses, in which the model shows a good overall performance.

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“…In particular for rocket applications, modeling these reactions is especially critical in hydrocarbon combustion, where the chemical time-scales are lower than in the case of hydrogen/oxygen chemistry. Efforts to model the influence of non-adiabatic effects on the gas composition, the associ-ated heat release and expected wall heat loads have been carried out using flamelet methods [4][5][6][7][8]. Studies aiming at quantifying the importance of the recombination reactions on heat loads augmentation have been carried out by considering methane/oxygen mixtures in rocket combustion chambers [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer augmentation by recombination reactions in turbulent reacting boundary layers at elevated pressures

Perakis¹,

Haidn²,

Ihme³

2021

Preprint

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A study of a reacting boundary layer flow with heat transfer at conditions typical for configurations at elevated pressures has been performed using a set of direct numerical simulations. Effects of wall temperatures are investigated, representative for cooled walls of gas turbines and sub-scale rocket engines operating with hydrocarbon as fuels. The results show that exothermic chemical reactions induced by the low-enthalpy in the boundary layer take place predominantly in the logarthimic sublayer. The majority of the heat release is attributed to the exothermic recombination of OH and CO to produce CO2 and H2O. The recombination reactions result in an increase of the wall heat loads by up to 20% compared to the inert flow. The gas composition experiences strong deviations from the chemical equilibrium conditions. In fact, a quenching of the major species is observed within the viscous sub-layer and the transition region. Analysis of chemical time-scales shows that the location of quenched composition coincides with the region where the Damköhler number decreases below unity. Within the viscous sub-layer, a secondary reaction zone is detected, involving the production of formyl and formaldehyde radicals that provide an additional source of energy release. The analysis of the reaction paths showed that reactions with zero activation energy are responsible for this change in gas composition, which also account for the initial branching of hydrocarbon fuels decomposition according to previous auto-ignition studies. The effect of the secondary recombination reactions is more prominent for the lower wall temperature case. Finally, the role of turbulent fluctuations on the species net chemical production rates is evaluated, showing a strong correlation between species and temperature fluctuations. This leads to a pronounced deviation of the mean reaction rates ω(Y k , T ) from the reaction rates obtained under the assumption of laminar finite rate.

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A Non-Adiabatic Flamelet Progress–Variable Approach for LES of Turbulent Premixed Flames

Cited by 15 publications

References 32 publications

The Effect of Partial Premixing and Heat Loss on the Reacting Flow Field Prediction of a Swirl Stabilized Gas Turbine Model Combustor

The Effect of Partial Premixing and Heat Loss on the Reacting Flow Field Prediction of a Swirl Stabilized Gas Turbine Model Combustor

Turbulent combustion modelling of a confined premixed jet flame including heat loss effects using tabulated chemistry

Heat transfer augmentation by recombination reactions in turbulent reacting boundary layers at elevated pressures

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