Detailed modelling of combustion systems

Oran, Elaine S.; Boris, J. P.

doi:10.1016/0360-1285(81)90014-9

Cited by 168 publications

(35 citation statements)

References 99 publications

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“…(1)- (6) It can be seen in Fig. 1 la that following an ini- (14) tial sharp drop due to compression by the piston, Pu/Pb remains nearly constant over most of the burning range. This is an extremely useful property and simplifies the approximate analysis of combustion in spark ignition engines.…”

Section: (17)mentioning

confidence: 92%

“…Mathematical theories have been proposed to deal with this problem [2][3][4][5][6][7][8], but no established physical description of a turbulent flow is yet available. The physics of turbulent flame propagation is even less well understood [9][10][11][12][13][14][15][16]. For these reasons, an attempt has been made in the present work to define quantities and obtain experimental estimates independently of physical models, so that the resulting experimental evidence may be used to test the assumptions of any physical model.…”

Section: Introductionmentioning

confidence: 99%

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Turbulent flame propagation and combustion in spark ignition engines

Beretta

Rashidi

Keck

1983

Combustion and Flame

158

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Pressure measurements synchronized with high-speed motion picture records of flame propagation have been made in a transparent piston engine. The data show that the initial expansion speed of the flame front is close to that of a laminar flame. As the flame expands, its speed rapidly accelerates to a quasi-steady value comparable with that of the turbulent velocity fluctuations in the unburned gas. During the quasi-steady propagation phase, a significant fraction of the gas behind the visible front is unburned. Final burnout of the charge may be approximated by an exponential decay in time.The data have been analyzed in a model independent way to obtain a set of empirical equations for calculating mass burning rates in spark ignition engines. The burning equations contain three parameters: the laminar burning speed st, a characteristic speed at, and a characteristic length IT. The laminar burning speed is known from laboratory measurements. Tentative correlations relating u T and IT to engine geometry and operating variables have been derived from the engine data.

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Section: (17)mentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Turbulent flame propagation and combustion in spark ignition engines

Beretta

Rashidi

Keck

1983

Combustion and Flame

158

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“…These equations have been derived and discussed extensively by Williams * (1965) and their numerical solution has been discussed, for example, by Oran and Boris (1981). They are the nonlinear, compressible partial differential equations describing a gas phase combustion system.…”

Section: A Basic Equationsmentioning

confidence: 99%

Chemical-acoustic interactions in combustion systems

Oran

Gardner

1985

Progress in Energy and Combustion Science

Self Cite

107

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“…In fact, most current engineering predictive procedures are based on such models. In the late 1970s with rapid development of supercomputer technology and the increased number of users of such technology, the method of "direct numerical simulation" (DNS) was introduced into turbulent combustion research (Oran and Boris, 1981). This method has since gained significant popularity; however, within the past decade its limitations in dealing with practical combustion problems have been widely recognized (Givi, 1994).…”

Section: Les Methodologymentioning

confidence: 99%

Les Software for the Design of Low Emission Combustion Systems for Vision 21 Plants

Smith¹,

Cannon²,

Adumitroaie³

et al. 2005

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In this project, an advanced computational software tool was developed for the design of low emission combustion systems required for Vision 21 clean energy plants. Vision 21 combustion systems, such as combustors for gas turbines, combustors for indirect fired cycles, furnaces and sequestrian-ready combustion systems, will require innovative low emission designs and low development costs if Vision 21 goals are to be realized. The simulation tool will greatly reduce the number of experimental tests; this is especially desirable for gas turbine combustor design since the cost of the high pressure testing is extremely costly. In addition, the software will stimulate new ideas, will provide the capability of assessing and adapting low-emission combustors to alternate fuels, and will greatly reduce the development time cycle of combustion systems.The revolutionary combustion simulation software is able to accurately simulate the highly transient nature of gaseous-fueled (e.g. natural gas, low BTU syngas, hydrogen, biogas etc.) turbulent combustion and assess innovative concepts needed for Vision 21 plants. In addition, the software is capable of analyzing liquid-fueled combustion systems since that capability was developed under a concurrent Air Force Small Business Innovative Research (SBIR) program. The complex physics of the reacting flow field are captured using 3D Large Eddy Simulation (LES) methods, in which large scale transient motion is resolved by time-accurate numerics, while the small scale motion is modeled using advanced subgrid turbulence and chemistry closures. In this way, LES combustion simulations can model many physical aspects that, until now, were impossible to predict with 3D steady-state Reynolds Averaged Navier-Stokes (RANS) analysis, i.e. very low NO x emissions, combustion instability (coupling of unsteady heat and acoustics), lean blowout, flashback, autoignition, etc. LES methods are becoming more and more practical by linking together tens to hundreds of PCs and performing parallel computations with fine grids (millions of cells). Such simulations, performed in a few weeks or less, provide a very cost-effective complement to experimental testing. In 5 years, these same calculations can be performed in 24 hours or less due to the expected increase of computing power and improved numerical techniques.This project was a four-year program. During the first year, the project included the development and implementation of improved chemistry (reduced GRI mechanism), subgrid turbulence (localized dynamic), and subgrid combustion-turbulence interaction (Linear Eddy) models into the CFD-ACE+ code. University expertise (Georgia Tech and University of California, Berkeley) was utilized to help develop and implement these advanced submodels into the unstructured, parallel CFD flow solver, CFD-ACE+. Efficient numerical algorithms that rely on in situ look-up tables or artificial neural networks were implemented for chemistry calculations. In the second year, the combustion LES software was ev...

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Detailed modelling of combustion systems

Cited by 168 publications

References 99 publications

Turbulent flame propagation and combustion in spark ignition engines

Turbulent flame propagation and combustion in spark ignition engines

Chemical-acoustic interactions in combustion systems

Les Software for the Design of Low Emission Combustion Systems for Vision 21 Plants

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