A Comparative Study of Subgrid Models, Reaction Mechanisms and Combustion Models in LES of Supersonic Combustion

2019 ◽  
Author(s):  
Christer Fureby
Keyword(s):  
Comparative Study ◽  
Reaction Mechanisms ◽  
Supersonic Combustion ◽  
Combustion Models

scholarly journals Comparative study of four reactions at onset of pre-equilibrium emission

2019 ◽  
Vol 223 ◽  
pp. 01010
Author(s):  
Magda Cicerchia ◽  
Fabiana Gramegna ◽  
Daniela Fabris ◽  
Tommaso Marchi ◽  
Marco Cinausero ◽  
...  
Keyword(s):  
Comparative Study ◽  
Nuclear Structure ◽  
Model Prediction ◽  
Reaction Mechanisms ◽  
Charged Particles ◽  
Decay Chain ◽  
Event Selection ◽  
Hot Nuclei ◽  
Light Charged Particles ◽  
Equilibrium Emission

The study of the emitted particles, comparing pre-equilibrium and thermal components, is a useful tool to examine the nuclear structure of emitters. Possible clustering effects, which may change the expected decay chain probability, could be highlighted on the competition between different reaction mechanisms. The NUCL-EX collaboration (INFN, Italy) has carried out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions 16O+30Si, 18O+28Si, 19F+27Al at 7 AMeV and 16O+30Si at 8 AMeV have been carried out using the GARFIELD+RCo array at Legnaro National Laboratories. Some anomalies in the α-particle emission channels have been evidenced in the measurement reported above, showing in an exclusive way the observed effects related to the entrance channels. The experimental results are compared to model prediction, for which the same filtering and complete event selection have been applied.

scholarly journals Comparison of Combustion Models for Lifted Hydrogen Flames within RANS Framework

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 152
Author(s):  
Ali Cemal Benim ◽  
Björn Pfeiffelmann
Keyword(s):  
Reaction Mechanism ◽  
Turbulent Combustion ◽  
Reaction Mechanisms ◽  
Numerical Study ◽  
Combustion Reaction ◽  
Combustion Model ◽  
Prediction Quality ◽  
Combustion Models ◽  
Wide Range ◽  
Lift Off

Within the framework of a Reynolds averaged numerical simulation (RANS) methodology for modeling turbulence, a comparative numerical study of turbulent lifted H2/N2 flames is presented. Three different turbulent combustion models, namely, the eddy dissipation model (EDM), the eddy dissipation concept (EDC), and the composition probability density function (PDF) transport model, are considered in the analysis. A wide range of global and detailed combustion reaction mechanisms are investigated. As turbulence model, the Standard k-ε model is used, which delivered a comparatively good accuracy within an initial validation study, performed for a non-reacting H2/N2 jet. The predictions for the lifted H2/N2 flame are compared with the published measurements of other authors, and the relative performance of the turbulent combustion models and combustion reaction mechanisms are assessed. The flame lift-off height is taken as the measure of prediction quality. The results show that the latter depends remarkably on the reaction mechanism and the turbulent combustion model applied. It is observed that a substantially better prediction quality for the whole range of experimentally observed lift-off heights is provided by the PDF model, when applied in combination with a detailed reaction mechanism dedicated for hydrogen combustion.

A Comparative Study of Combustion Models for Spark Ignition Engines Based on Experimentation and CFD Simulation

2010 ◽  
Author(s):  
Raouf Mobasheri ◽  
M. Sadegh Shahrokhi-Dehkordi
Keyword(s):  
Comparative Study ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Experimental Tests ◽  
Experimental Results ◽  
Nox Emission ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Flamelet Model ◽  
Combustion Models

Computational fluid dynamics (CFD) is able to significantly reduce the number of experimental tests and measurements and lower the development time and costs. However some parameters which are needed for CFD calculation must be achieved experimentally. In this paper, a comparative study was carried out to clarify the effect of three different combustion models on the prediction capability of combustion process and NOx emission on a modified 4-cylinder MPFI SI engine. Validation of the combustion model has been performed through comparing simulation data with the experimental results and a satisfactory agreement between them has been achieved in terms of combustion parameters and NOx emission. The results show that, applying appropriate constants of each combustion model including Eddy break up model (Ebu), Probability density function (Pdf) and Coherent flamelet model (Cfm) causes the computational results to be in agreement with experimental results. Furthermore the results show that the nearest prediction in comparison with experimental results is by applying the Ebu model.

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