Views
2 years ago

Sensitivity calculations in PDF modelling of turbulent flames

Sensitivity calculations in PDF modelling of turbulent flames

Sensitivity calculations in PDF modelling of turbulent

Available online at www.sciencedirect.comProceedings of the Combustion Institute 32 (2009) 1629–1637Proceedingsof theCombustionInstitutewww.elsevier.com/locate/prociSensitivity calculations in PDF modellingof turbulent flamesZhuyin Ren * , Stephen B. PopeSibley School of Mechanical and Aerospace Engineering, Cornell University, Rhodes Hall 101, Ithaca, NY 14853, USAAbstractIn modelling turbulent combustion, it is desirable to know the sensitivities of the predictions to certainparameters. Recently, a method for calculating particle-level sensitivities in PDF modelling of turbulentcombustion has been described by Ren and Pope [1]. In this work, we develop a methodology for the efficientcalculation of these particle-level sensitivities using in situ adaptive tabulation. In addition, PDF calculationswith sensitivities of the Cabra H 2 /N 2 jet flame are performed to investigate the sensitivities of thepredictions to certain important parameters. The accuracy of the proposed methodology is demonstratedby comparing its prediction of sensitivities with those obtained by divided difference. For the Cabra flame,the sensitivities confirm that the predictions are extremely sensitive to the coflow temperature: the sensitivitiesto coflow temperature are about 10 times larger than those to chemistry, and about 100 times largerthan those to the mixing model constant. The particle-level sensitivities show that, at the flame base, strongchemical reactions start at in very fuel-lean region, which indicates that this region is important to the stabilizationof the flame. The sensitivities also indicate the physical regions where the effects of differentparameters are significant. Further insights are obtained by investigating the compositions and the sensitivityvectors in the composition space. The most sensitive particles are found to lie close to a saddle-shapedtwo-dimensional manifold, and the sensitivity vectors are generally tangential to the manifold. The singularvalue decomposition of the sensitivity matrices reveals that there is only one significant singular value andhence there is a dominant direction of the response to a change in the sensitivity parameters considered.Similarities in particle sensitivities are also illustrated. Similar PDF calculations (with sensitivities) ofthe Barlow and Frank flame F are reported in the Supplementary material.Ó 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.Keywords: Sensitivity analysis; In situ adaptive tabulation; Particle-level sensitivities; Local extinction/re-ignition; PDFmethods1. Introduction* Corresponding author. Address: ANSYS Inc., 10Cavendish Court, Lebanon, NH 03766, USA. Fax: +1603 643 3967.E-mail address: zr26@cornell.edu (Z. Ren).Modelling combustion phenomena requiresthe knowledge of chemical kinetics, transportproperties, turbulence/combustion model parameters,etc. as input parameters, and produces predictions(such as species concentration profiles,etc.) as the output, with the input and the outputbeing connected by the governing model equations.Often it is desirable to know how sensitivethe predictions are to certain parameters in themodel formulation. In the fields of chemical kineticsand laminar flames, sensitivity analysis [2–4]has been widely used to examine quantitatively1540-7489/$ - see front matter Ó 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.doi:10.1016/j.proci.2008.05.074

Modelling Your Armiya Krajowa PDF... - Flames of War
Sensitivity analysis of a complex global aerosol model to - MUCM
Consistent calculation of multiple system models and ... - EcoInvent
Set Point Calculation Model for a Paper Mill Power ... - Tech4CDM
APPLICATIONS OF TURBULENCE MODELS - VBN
Turbulence closures for ocean models - lseet
Sensitivity of ARGO-YBJ to different composition models in the ...
Modelling of turbulent flows applied to numerical simulations of ...
Application of a Shelterbelt Turbulence Model to Simulate Drag
pdf - Computational Modeling and Analysis for Complex Systems
Turbulence- and particle-resolving numerical modeling of ... - CSDMS
Conference on MODELLING FLUID FLOW - Turbulence Mechanics ...
SG2218 – 2012 Turbulence models for CFD SG2218 – 2012 ... - KTH
Green Infrastructure Models and Calculators (PDF) - Water
pdf - Computational Modeling and Analysis for Complex Systems
PDF Calculations of a Turbulent Flame - Turbulence and ...
Joint PDF Closure of Turbulent Premixed Flames - Italian Section of ...
Modelling Turbulent Non-premixed Flames Using a Reactant Plan ...
PDF Model Calculations of Compressible Turbulent Flows Using ...
A revised EBU type model for turbulent premixed flames based on ...
Measurement of flame surface density for turbulent premixed flames ...
Calculations of a Turbulent Bluff-Body Stabilized Flame K. Liu , S. B. ...
chapter 5 turbulent diffusion flames - FedOA
Numerical Simulation of Turbulent Premixed Flames with ...
Calculating soot in a turbulent jet diffusion flame using the unsteady ...
Turbulent lifted flames in a vitiated coflow investigated using joint ...
Measurement of turbulent transport in premixed turbulent flames by ...
Determination of the Heat Release Distribution in Turbulent Flames ...
DNS of Turbulent Nonpremixed Ethylene Flames