Assessing LES models based on tabulated chemistry for the simulation of Diesel spray combustion

Tillou, Julien; Michel, Jean‐Baptiste; Angelberger, Christian; Veynante, Denis

doi:10.1016/j.combustflame.2013.09.006

Cited by 65 publications

(33 citation statements)

References 48 publications

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“…Still Eulerian methods have been applied with success to mechanical engineering problems, especially when the coupling is strong (through two-way momentum and heat transfers or through evaporation and combustion). Examples of applications are gas turbine ignition [13], Diesel spray polydisperse evaporation [42,61] and combustion LES [88], SRB hydroacoustic [39] and thermoacoustic [83] instabilities, and fluidized beds [44]. Eulerian methods have been acknowledged for their good coupling and parallel properties in the spray [13,37] and plasma communities [52].…”

Section: Introductionmentioning

confidence: 99%

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

Doisneau

Arienti

Oefelein

2017

Journal of Computational Physics

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For sprays, as described by a kinetic disperse phase model strongly coupled to the Navier-Stokes equations, the resolution strategy is constrained by accuracy objectives, robustness needs, and the computing architecture. In order to leverage the good properties of the Eulerian formalism, we introduce a deterministic particle-based numerical method to solve transport in physical space, which is simple to adapt to the many types of closures and moment systems. The method is inspired by the semi-Lagrangian schemes, developed for Gas Dynamics. We show how semi-Lagrangian formulations are relevant for a disperse phase far from equilibrium and where the particle-particle coupling barely influences the transport; i.e., when particle pressure is negligible. The particle behavior is indeed close to free streaming. The new method uses the assumption of parcel transport and avoids to compute fluxes and their limiters, which makes it robust. It is a deterministic resolution method so that it does not require efforts on statistical convergence, noise control, or post-processing. All couplings are done among data under the form of Eulerian fields, which allows one to use efficient algorithms and to anticipate the computational load. This makes the method both accurate and efficient in the context of parallel computing. After a complete verification of the new transport method on various academic test cases, we demonstrate the overall strategy's ability to solve a strongly-coupled liquid jet with fine spatial resolution and we apply it to the case of high-fidelity Large Eddy Simulation of a dense spray flow. A fuel spray is simulated after atomization at Diesel engine combustion chamber conditions. The large, parallel, strongly coupled computation proves the efficiency of the method for dense, polydisperse, reacting spray flows.

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Section: Introductionmentioning

confidence: 99%

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

Doisneau

Arienti

Oefelein

2017

Journal of Computational Physics

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“…Bekdemir et al [43], Tillou et al [44] Eulerian (downstream inj.) 1.1 TPDF-LES (fuel is heptane) Xue et al [45], Senecal et al [10,46], Hu et al [47] DSMC (0.8 Mp) < 1.4 RD-KHRT-LES Gong et al [48,49] DSMC (0.5 Mp) 1.4 HG-WAVE-CCM-LES Abraham and Pickett [9] Equivalent Gas 2.0 2DRANS Pei et al […”

Section: Discussionmentioning

confidence: 99%

“…At too coarse a resolution, Eulerian models reach a limit of validity because they encounter mesh diffusion errors on the liquid mass concentration, which explains why the scarce group-2 Eulerian simulations [43,44] use a purposely designed "downstream-injection" numerical technique, while group-1 simulations use DSMC. DSMC holds at coarse resolution thanks to its more accurate representation of the mass concentration field since the parcel trajectories are computed to machine precision.…”

Section: On the Operating Resolution Of Spray Modelsmentioning

confidence: 99%

On Multi-Fluid models for spray-resolved LES of reacting jets

Doisneau

Arienti

Oefelein

2017

Proceedings of the Combustion Institute

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Numerical simulation of sprays can potentially be used for assessing the performance and variability of engines. But today's simulations only provide average quantities, after calibration. Spray injection can be thought of as a multiscale problem with 4 levels (chamber, mixing layer, drop scale, and nozzle). Because of their complex interactions, increasing predictivity requires simulations to capture more of these scales. To assess the trade-offs in this regard, we perform a review of recent Diesel spray simulations. After highlighting the importance of the mixing layer in driving spray dynamics, we analyze various two-phase flow formalisms and show the potential benefits of a Eulerian spray formulation combined with Large Eddy Simulation (LES) to capture a variable-density mixing layer (VDML). We then present a framework and numerical methods to make this description operative and show how it performs on a realistic autoignition case called Spray A.

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“…Consequently, the ADF model establishes two hypotheses, namely, to solve only the flamelet equation for the progress variable and to decouple the chemical source term of the diffusion processes. Although, at first glance, it may seem very restrictive constrains this model has been successfully applied to diesel-like sprays [6], diesel engines and furnaces [5,14,15]. For this work, the progress variable is defined as Yc = YCO + YCO 2 [4].…”

Section: Model Descriptionmentioning

confidence: 99%

“…These aspects are covered by flamelet models used together with tabulated chemistry and, more particularly, by the Approximated Diffusion Flamelet (ADF) approach [4]. This model, used in the present work, has been demonstrated to offer powerful capabilities and provides satisfactory results in the frame of diesel sprays and diesel engines simulations [5,6]. Nevertheless, the fuel oxidation process, given by the chemical mechanism, arises as one of the cornerstones in the combustion numerical simulation and is one of the inputs to the problem which causes a greater uncertainty.…”

Section: Introductionmentioning

confidence: 99%

Influence of the chemical mechanism in the frame of diesel-like CFD reacting spray simulations using a presumed PDF flamelet-based combustion model

González

Oliver

Novella

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The ability of a computational fluid dynamics (CFD) simulation to reproduce the diesel-like reacting spray ignition process and its corresponding flame structure strongly depends on both the fidelity of the chemical mechanism for reproducing the oxidation of the fuel and also on how the turbulence-chemistry interaction (TCI) is modeled. Therefore, investigating the performance of different chemical mechanisms not only in perfect stirred reactors but directly in the diesel-like spray itself is of great interest in order to evaluate their suitability for being further applied to CFD engine simulations. This research work focuses on applying a presumed probability density function (PDF) unsteady flamelet combustion model to the well-known spray A from the Engine Combustion Network (ECN), using three chemical mechanisms widely accepted by the scientific community as a way to figure out the influence of chemistry in the key characteristics of the combustion process in the frame of diesel-like spray simulations. Results confirm that in spite of providing all of them correct trends for ignition delays (ID) and lift-off lengths (LOL), when comparing with experimental results, the structure of the flame presents noticeable differences, especially in the low and intermediate temperatures and high equivalence ratio regions. Consequently, the selection of the chemical mechanism has an impact on the zones of influence of key species as observed in both spatial coordinates and also in the equivalence ratio-temperature maps. These differences are expected to be relevant considering the implications when coupling pollutant emissions models. The analysis of temperature and oxygen concentration parametric studies evidences how the observed differences are consistent and moderately dependent on the ambient conditions. KeywordsCombustion modeling, Chemical mechanism, Spray A, Flamelet IntroductionThe improvement of the combustion technologies in industrial devices, such as diesel engines, in terms of efficiency and pollutant emissions, evidence that a comprehensive knowledge of the processes involved is mandatory. Between the different processes that concur in the energetic transformation, turbulent non-premixed combustion appears as one of the most relevant. Nevertheless, its modeling is a complex issue due to the different length and time scales of the turbulence, the fuel oxidation and the interaction between them [1]. These considerations point out that for a proper modeling of the turbulent non-premixed combustion two main aspects are essential. The first one is the chemical mechanism, that determines the fuel oxidation, while the second one is the turbulence-chemistry interaction (TCI). Promoted by the need of gaining a very detailed knowledge in these issues in diesel spray conditions, the Engine Combustion Network (ECN) has proposed a set of experiments in controlled conditions that shed light for these concerns by means of experiments and numerical simulations. More particularly, the well-known spray A models a die...

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Assessing LES models based on tabulated chemistry for the simulation of Diesel spray combustion

Cited by 65 publications

References 48 publications

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

On Multi-Fluid models for spray-resolved LES of reacting jets

Influence of the chemical mechanism in the frame of diesel-like CFD reacting spray simulations using a presumed PDF flamelet-based combustion model

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