A Numerical Study of the Effect of EGR on Flame Lift-off in n-Heptane Sprays Using a Novel PaSR Model Implemented in OpenFOAM

Kösters, Anne; Golovitchev, Valeri

doi:10.4271/2012-01-0153

Cited by 9 publications

(6 citation statements)

References 12 publications

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“…The transport equations for the reactor density and enthalpy are defined corresponding to equation (14). Here, the model defined in [3] is expanded upon by the definition of a reactor density, ρ R . The mixing term defines the interactions between the properties of the reactor and the mean properties of the cell.…”

Section: Vrfmmentioning

confidence: 99%

“…We therefore sought to compare the performance of the different models side-by-side using an identical computational configuration in each case, with minimal differences between the numerical set-ups used for each model. To this end, we compared the Volume Reactor Fraction Model (VRFM) [3], the multiple representative interactive flamelet (mRIF) model [4], and the well-stirred reactor (WS) model using the open-source software package OpenFOAM R . The VRFM describes the turbulence-chemistry interaction with a partially stirred reactor (PaSR) approach [5].…”

Section: Introductionmentioning

confidence: 99%

“…The main difference between the VRFM and the EDC is the definition of the reactor volume. The VRFM has previously been used to investigate the effects of the EGR level on the flame lift-off length [3]. In both models, chemical conversion takes place in a perfectly stirred reactor, i.e., they do not consider any (underlying laminar) flame structure.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach

Kösters

Oevermann

D’Errico

2015

Combustion Theory and Modelling

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The flame stabilization process in turbulent non-premixed flames is not fully understood and several models have been developed to describe the turbulence-chemistry interaction. This work compares the performance of the multiple representative interactive flamelet (mRIF) model, the Volume Reactor Fraction Model (VRFM), and the well stirred reactor (WS) model in describing such flames. The predicted ignition delay and flame lift-off length of n-heptane sprays are compared to experimental results published within the Engine Combustion Network (ECN). All of the models predict the trend of ignition delay reasonably well. At a low gas pressure (42 bar) the ignition delay is overpredicted compared to the experimental data, but the difference between the models is not significant. However, the predicted lift-off lengths differ. At high pressure (87 bar) the difference between the models is small. All models slightly underpredict the lift-off length compared to the experimental data. At low gas pressure (42 bar) the mRIF model gives best results. The VRFM and the WS model predict excessively short lift-off lengths, but the VRFM gives better results than the WS model. The flame structures of the models are also compared. The WS model and the VRFM yield a well defined flame stabilization point whereas the mRIF model does not. The flame of the mRIF model is more diffuse and the model is not able to predict flame propagation. All models were able to predict the experimental trends in lift-off and ignition delay, but certain differences between them are demonstrated.

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Section: Vrfmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach

Kösters

Oevermann

D’Errico

2015

Combustion Theory and Modelling

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“…In this paper, with that aim, the LES/EPaSR model recently developed by Sabelnikov and Fureby [11,12] has been adapted to the RANS simulation. It is worth to mention that PaSR model was improved as well in [5,13] using the additional transport equations for the reactor species. The concept of the model is based on the experimental results of Batchelor and Townsend [14] showing that at high Reynolds numbers, turbulent ¦ne structure is not uniformly distributed in space but concentrated in small isolated regions, whose volume is a small fraction of the total volume.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of a backward-facing step combustor using reynolds-averaged navier–stokes / extended partially stirred reactor model

Petrova

Sabelnikov

Bertier

2019

Progress in Propulsion Physics – Volume 11

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The authors adapt recently developed a large eddy simulation / extended partially stirred reactor (LES/EPaSR) model by Sabelnikov and Fureby for simulation of turbulent combustion to Reynolds-averaged Navier–Stokes (RANS) equations. The proposed RANS/EPaSR model is validated against experimental database created at ONERA for an air–methane premixed flame stabilized by a backward-facing step combustor. The RANS/EPaSR model is compared also with the following RANSbased combustion models: (i) quasi-laminar model with reduced chemical mechanism (QL RCM); (ii) premixed flamelet tabulated chemistry (PFTC) without taking into account the turbulence–chemistry interaction (TCI); and (iii) a PFTC with a presumed β probability density function (PDF) for a progress combustion variable.

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“…However, if the chemical time scales are not fast compared to the fastest turbulent time scales (as is the case during low temperature combustion, ignition, and re-ignition), it becomes essential to accurately describe the interactions between chemistry, molecular transport, and turbulence in order to obtain realistic results. Other popular classes of combustion model for engine applications involving non-premixed combustion are stirred/partially stirred reactor models and the volume reactor fraction model (VRFM) [3], in which the chemistry is directly integrated. However, these models do not provide a characteristic length or velocity scale of combustion and therefore cannot predict/model flame structure.…”

Section: Introductionmentioning

confidence: 99%

A Representative Interactive Linear Eddy Model (RILEM) for Non-Premixed Combustion

Lackmann

Kerstein

Oevermann

2015

SAE Technical Paper Series

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To further improve the efficiency and emissions profiles of internal combustion engines, many new combustion concepts are currently being investigated. Examples include homogeneous charge compression ignition (HCCI), stratified charge compression ignition (SCCI), lean stratified premixed combustion, and the use of high levels of exhaust gas recirculation (EGR) in diesel engines. The typical combustion temperatures in all of these concepts are lower than those in traditional spark ignition or diesel engines. Most of the combustion models that are currently used in computational fluid dynamics (CFD) simulations were developed to describe either premixed or non-premixed combustion under the assumption of fast chemistry. The refinement of existing combustion concepts for highly efficient clean engines and the development of new ones would be greatly facilitated by the introduction of new computational tools and combustion models that are mode-and regimeindependent, i.e. capable of modeling both premixed and nonpremixed and also fast and non-fast chemistry. Such tools should enable more accurate simulation of combustion under non-standard conditions such as those established during low temperature combustion. This paper presents a new regime-independent combustion modeling strategy for non-premixed combustion in which the linear eddy model (LEM) is used as a representative interactive regime-independent turbulent combustion model and coupled to a 3D CFD solver. Parameters and boundary conditions that determine the evolution of the LEM are supplied by the 3D CFD calculation and updated at each time step. The LEM is then solved for the corresponding time step, providing the 3D CFD code with an updated composition state. This new representative interactive linear eddy model (RILEM) is used to simulate an n-heptane spray, demonstrating some potential to describe spray combustion processes.

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A Numerical Study of the Effect of EGR on Flame Lift-off in n-Heptane Sprays Using a Novel PaSR Model Implemented in OpenFOAM

Cited by 9 publications

References 12 publications

RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach

RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach

Numerical simulation of a backward-facing step combustor using reynolds-averaged navier–stokes / extended partially stirred reactor model

A Representative Interactive Linear Eddy Model (RILEM) for Non-Premixed Combustion

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