Application of LES-PDF Methods on Turbulent Reacting Flows

Application of LES-PDF Methods on Turbulent Reacting Flows PDF Author: Ilias Dodoulas
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Category :
Languages : en
Pages :

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Application of LES-PDF Methods on Turbulent Reacting Flows

Application of LES-PDF Methods on Turbulent Reacting Flows PDF Author: Ilias Dodoulas
Publisher:
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Category :
Languages : en
Pages :

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Application of PDF Methods to Compressible Turbulent Reacting Flows

Application of PDF Methods to Compressible Turbulent Reacting Flows PDF Author: Bertrand Delarue
Publisher:
ISBN:
Category :
Languages : en
Pages : 234

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Computational Models for Turbulent Reacting Flows

Computational Models for Turbulent Reacting Flows PDF Author: Rodney O. Fox
Publisher: Cambridge University Press
ISBN: 9780521659079
Category : Mathematics
Languages : en
Pages : 156

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Table of contents

Calculations of Turbulent Reacting Flows Using PDF Methods

Calculations of Turbulent Reacting Flows Using PDF Methods PDF Author: David Henry Rowinski
Publisher:
ISBN:
Category :
Languages : en
Pages : 202

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This work presents applications of the probability density function (PDF) method to several recently-developed turbulent flows, and the implementation and assessment of several sub-models. A series of lean piloted premixed jet flames (in order of lowest to highest jet bulk velocity: PM1-50, PM1-100, PM1150, and PM1-200) is first studied using a Reynolds-Averaged Navier-Stokes (RANS) based PDF method. These calculations use diagnostic testing and thorough parametric studies of models to show that the standard models overpredict the reaction rate in the flames PM1-150 and PM1-200. The nature of the combustion in these flames is examined through comparison to simpler combustion models, and it is found to be similar to laminar non-premixed flames. These same flames are then investigated further using both RANS-PDF and the recently developed Large Eddy Simulation (LES) PDF method. Simple models for molecular diffusion and combustion are tested and implemented in the RANS-PDF calculations. In the LES-PDF calculations, the effects of differential diffusion and the mixing model constant, C M, are both examined, and the calculations are found to be very sensitive to the value of C M . This study yields substantially improved calculations of all the flames. In particular, the study of C M shows strong evidence that larger values of C M are necessary for flames PM1-150 and PM1-200. The modeling of molecular mixing is investigated further through a study of a non-reacting turbulent jet flow with three inflowing streams. This study presents the unique opportunity to compare the scalar dissipation rate and conditional diffusion from the calculations to experimental data. In the RANS-PDF calculations of this flow, three classic mixing models are evaluated. The joint scalar PDF's are very sensitive to the choice of mixing model and show a wide variability from the measurements. Only the Euclidean Minimum Spanning Tree (EMST) produces compositions which lie very close to the slow manifold identified in the experimental work. LES calculations of the same flow are performed, and the dissipation rate and conditional diffusion are calculated. The resolved scalar dissipation rate is found to be in good agreement with the experimental data, but depends strongly on the resolution; the total dissipation rate from the RANS-PDF and LES calculations indicates significantly larger scalar dissipation rates than those measured experimentally. Lastly, LES-PDF calculations of the same flow yield joint-PDF's in very good agreement with the experimental data, and are far-improved from those of any mixing model studied with RANS-PDF. The attenuation of variance production model is introduced for LES-PDF and tested in this flow. This new model results in an additional dissipation of scalar variance and yields calculations of improved accuracy on coarse grids.

Application of a Pdf Method to Compressible Turbulent Reacting Flows

Application of a Pdf Method to Compressible Turbulent Reacting Flows PDF Author: A. T. Hsu
Publisher:
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Category :
Languages : en
Pages :

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An Introduction To Turbulent Reacting Flows

An Introduction To Turbulent Reacting Flows PDF Author: Epaminondas Mastorakos
Publisher: World Scientific Publishing Company
ISBN: 1911298429
Category : Technology & Engineering
Languages : en
Pages : 192

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Book Description
This book provides physical intuition and key entries to the ever-growing body of literature on turbulent reacting flows. It is of a tutorial nature and includes some historical perspective of the theories developed over the past 30 years. A selection of basic and advanced materials is used to build the necessary background and emphasize some of the main concepts that the student or newcomer to the field of turbulent reacting flows should know, thus facilitating further study of specialized research papers and research monographs. A range of exercises is also provided in order to consolidate the student's understanding./a

LES/PDF Approach for Turbulent Reacting Flows

LES/PDF Approach for Turbulent Reacting Flows PDF Author: Pratik Prakash Donde
Publisher:
ISBN:
Category :
Languages : en
Pages : 220

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Book Description
The probability density function (PDF) approach is a powerful technique for large eddy simulation (LES) based modeling of turbulent reacting flows. In this approach, the joint-PDF of all reacting scalars is estimated by solving a PDF transport equation, thus providing detailed information about small-scale correlations between these quantities. The objective of this work is to further develop the LES/PDF approach for studying flame stabilization in supersonic combustors, and for soot modeling in turbulent flames.

Les, DNS and Rans for the Analysis of High-Speed Turbulent Reacting Flows

Les, DNS and Rans for the Analysis of High-Speed Turbulent Reacting Flows PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781723192067
Category :
Languages : en
Pages : 126

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The purpose of this research is to continue our efforts in advancing the state of knowledge in large eddy simulation (LES), direct numerical simulation (DNS), and Reynolds averaged Navier Stokes (RANS) methods for the computational analysis of high-speed reacting turbulent flows. In the second phase of this work, covering the period 1 Sep. 1993 - 1 Sep. 1994, we have focused our efforts on two research problems: (1) developments of 'algebraic' moment closures for statistical descriptions of nonpremixed reacting systems, and (2) assessments of the Dirichlet frequency in presumed scalar probability density function (PDF) methods in stochastic description of turbulent reacting flows. This report provides a complete description of our efforts during this past year as supported by the NASA Langley Research Center under Grant NAG1-1122. Givi, Peyman and Taulbee, Dale B. and Adumitroaie, Virgil and Sabini, George J. and Shieh, Geoffrey S. Unspecified Center COMPUTATIONAL FLUID DYNAMICS; PROBABILITY DENSITY FUNCTIONS; REACTING FLOW; STOCHASTIC PROCESSES; TURBULENT FLOW; DIRICHLET PROBLEM; HIGH SPEED; MIXING LAYERS (FLUIDS); NAVIER-STOKES EQUATION; VORTICES...

Hybrid LES-PDF Methods for the Simulation of Turbulent Reactive Flows

Hybrid LES-PDF Methods for the Simulation of Turbulent Reactive Flows PDF Author: Venkatramanan Raman
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :

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A PDF Approach for Compressible Turbulent Reacting Flows

A PDF Approach for Compressible Turbulent Reacting Flows PDF Author: A. T. Hsu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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