Direct numerical simulations and analysis of three-dimensional n-heptane spray flames in a model swirl combustor

Luo, Kun; Pitsch, Heinz; Pai, Madhusudan; Desjardins, Olivier

doi:10.1016/j.proci.2010.06.077

Cited by 159 publications

(64 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A model is therefore needed for the description of the resulting dispersed liquid phase that is injected in the simulations, (2) The evolution of the droplet mist has to be described at a computational cost consistent with the available resources. Two main approaches exist for the large eddy simulation of two-phase reacting flows, both relying on mesoscopic models [12]: the Eulerian-Eulerian approach, where moments of the number density function (NDF) are transported [13,14] and the Eulerian-Lagrangian model where a set of individual particles are being tracked [15][16][17]. In the Eulerian-Lagrangian framework, it is relatively easy to account for polydispersion, while the Eulerian-Eulerian approach requires an additional set of transport equations for each moment and/or class of particle sizes, notably increasing the computational cost.…”

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of Light-Round in an Annular Combustor With Liquid Spray Injection and Comparison With Experiments

Lancien

Prieur

Durox

et al. 2017

Volume 4A: Combustion, Fuels and Emissions

View full text Add to dashboard Cite

The light-round is defined as the process by which the flame initiated by an ignition spark propagates from burner to burner in an annular combustor, eventually leading to a stable combustion. Combining experiments and numerical simulation, it was recently demonstrated that under perfectly premixed conditions this process could be suitably described by large eddy simulation (LES) using massively parallel computations. The present investigation aims at developing light-round simulations in a configuration that is closer to that found in aero-engines by considering liquid nheptane injection. The large-eddy simulation of the ignition sequence of a laboratory scale annular combustion chamber comprising sixteen swirled spray injectors is carried out with a mono-disperse Eulerian approach for the description of the liquid phase. The objective is to assess this modeling approach of the two-phase reactive flow during the ignition process. The simulation results are compared in terms of flame structure and light-round duration to the corresponding experimental images of the flame front recorded by a high-speed intensified CCD camera and to the corresponding experimental delays. The dynamics of the flow is also analyzed to identify and characterize mechanisms controlling flame propagation during the light-round process.

show abstract

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of Light-Round in an Annular Combustor With Liquid Spray Injection and Comparison With Experiments

Lancien

Prieur

Durox

et al. 2017

Volume 4A: Combustion, Fuels and Emissions

View full text Add to dashboard Cite

show abstract

“…The initial droplet diameters are set to 1.33 mm for a single fuel droplet and 7.5, 15 µm for multiple fuel droplets. These droplet sizes are decided to compare with the experiments [24] and to meet the requirement associate with the grid size from the point of view of numerical accuracy, respectively (the grid spacing needs to be roughly 10 times larger than the droplet size [10]). The initial gas and droplet temperature are 1500 K and 300 K, respectively.…”

Section: Computational Detailsmentioning

confidence: 99%

“…Recently, the spray combustion behavior has been studied by means of two-or three-dimensional direct numerical simulations (DNSs) (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]) or largeeddy simulations (LESs) (e.g., [19][20][21][22][23]). However, the mechanism of spray combustion has not been fully understood yet.…”

Section: Introductionmentioning

confidence: 99%

Evaporation and combustion of multicomponent fuel droplets

Kitano

Nishio

Kurose

et al. 2014

Fuel

View full text Add to dashboard Cite

The effects of difference in fuel components on the droplet evaporation and combustion are numerically investigated. Jet-A is used as liquid fuel, and one (n-decane)-, two (n-decane and 1,2,4-trimethyl-benzene)-and three (n-dodecane, iso-octane and toluene)-component fuels are used as the surrogate fuels of Jet-A. The results show that the evaporation of the three-component surrogate fuel becomes faster and slower than those of the one-and two-component surrogate fuels in the initial and subsequent evaporating periods, respectively. The differences in the gas temperature evolution among these three different surrogate fuels are remarkable right after the ignition, but become small with time.

show abstract

“…This simple example therefore serves to illustrate the predictive capability of the mixture-fraction formalism in computations of spray diffusion flames with fast chemistry, when appropriate account is taken of the spray-source terms affecting Z and H in their conservation equations. Gas-phase mixture fractions analogous to (7.2) have been used widely in turbulent spray flames for analyses of direct numerical simulation results (Reveillon & Versvich 2000;Reveillon & Vervisch 2005;Luo et al 2011) and for flamelet combustion modelling with finite-rate chemistry (Baba & Kurose 2008;Franzelli, Fiorina & Darabiha 2013).…”

Section: The Gas-phase Mixture Fractionmentioning

confidence: 99%

“…Because of their key role in numerous technological applications, combustion and vaprization of fuel sprays have been the subject of many modelling efforts (see Faeth 1983;Sirignano 1983;Williams 1985;Annamalai & Ryan 1992;Li 1997;Aggarwal 1998;Crowe, Sommerfeld & Tsuji 1998 Knudsen & Pitsch 2010;Luo et al 2011;Shashank 2011;Neophytou, Mastorakos & Cant 2012), including disparate length and time scales associated with the chemistry and with the multiphase nature of the flow, which is highly turbulent in most applications.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of thermal ignition of spray flames in mixing layers

et al. 2013

View full text Add to dashboard Cite

Conditions are identified under which analyses of laminar mixing layers can shed light on aspects of turbulent spray combustion. With this in mind, laminar spray-combustion models are formulated for both non-premixed and partially premixed systems. The laminar mixing layer separating a hot-air stream from a monodisperse spray carried by either an inert gas or air is investigated numerically and analytically in an effort to increase understanding of the ignition process leading to stabilization of high-speed spray combustion. The problem is formulated in an Eulerian framework, with the conservation equations written in the boundary-layer approximation and with a one-step Arrhenius model adopted for the chemistry description. The numerical integrations unveil two different types of ignition behaviour depending on the fuel availability in the reaction kernel, which in turn depends on the rates of droplet vaporization and fuel-vapour diffusion. When sufficient fuel is available near the hot boundary, as occurs when the thermochemical properties of heptane are employed for the fuel in the integrations, combustion is established through a precipitous temperature increase at a well-defined thermal-runaway location, a phenomenon that is amenable to a theoretical analysis based on activation-energy asymptotics, presented here, following earlier ideas developed in describing unsteady gaseous ignition in mixing layers. By way of contrast, when the amount of fuel vapour reaching the hot boundary is small, as is observed in the computations employing the thermochemical properties of methanol, the incipient chemical reaction gives rise to a slowly developing lean deflagration that consumes the available fuel as it propagates across the mixing layer towards the spray. The flame structure that develops downstream from the ignition point depends on the fuel considered and also on the spray carrier gas, with fuel sprays carried by air displaying either a lean deflagration bounding a region of distributed reaction or a distinct double-flame structure with a rich premixed flame on the spray side and a diffusion flame on the air side. Results are calculated for the distributions of mixture fraction and scalar dissipation rate across the mixing layer that reveal complexities that serve to identify differences between spray-flamelet and gaseous-flamelet problems.

show abstract

Direct numerical simulations and analysis of three-dimensional n-heptane spray flames in a model swirl combustor

Cited by 159 publications

References 13 publications

Large-Eddy Simulation of Light-Round in an Annular Combustor With Liquid Spray Injection and Comparison With Experiments

Large-Eddy Simulation of Light-Round in an Annular Combustor With Liquid Spray Injection and Comparison With Experiments

Evaporation and combustion of multicomponent fuel droplets

Dynamics of thermal ignition of spray flames in mixing layers

Contact Info

Product

Resources

About