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The role of presumed probability density function in the simulation of non premixed turbulent combustion

2013/05/25 by Alessandro Coclite, Coclite, Alessandro, G. Pascazio +7
Chemical Engineering · Engineering · Physics and Astronomy · #Advanced Combustion Engine Technologies #Combustion and flame dynamics #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Fire dynamics and safety research #Fluid Dynamics (physics.flu-dyn) #Radiative Heat Transfer Studies #physics.comp-ph #physics.flu-dyn

paper · pdf · doi:10.48550/arxiv.1305.5893

EUCASS 2013 proceedings

openalex publication_date 2013/05/25 · arxiv created 2014/01/21 · arxiv updated 2014/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Flamelet Progress Variable (FPV) combustion models allow the evaluation of all thermo chemical quantities in a reacting flow by computing only the mixture fraction Z and a progress variable C. When using such a method to predict a turbulent combustion in conjunction with a turbulence model, a probability density function (PDF) is required to evaluate statistical averages (e.g., Favre average) of chemical quantities. The choice of the PDF is a compromise between computational costs and accuracy level. The aim of this paper is to investigate the influence of the PDF choice and its modeling aspects in the simulation of non premixed turbulent combustion. Three different models are considered: the standard one, based on the choice of a beta distribution for Z and a Dirac distribution for C; a model employing a beta distribution for both Z and C; a third model obtained using a beta distribution for Z and the statistical most likely distribution (SMLD) for C. The standard model, although widely used, doesn't take into account the interaction between turbulence and chemical kinetics as well as the dependence of the progress variable not only on its mean but also on its variance. The SMLD approach establishes a systematic framework to incorporate informations from an arbitrary number of moments, thus providing an improvement over conventionally employed presumed PDF closure models. The rational behind the choice of the three PDFs is described in some details and the prediction capability of the corresponding models is tested versus well known test cases, namely, the Sandia flames, and a test case for supersonic combustion provided by Cheng.

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