A Combined Level-Set/Mixture Fraction/Progress-Variable Approach for Partially-Premixed Turbulent Reacting Flows

2007 ◽  
Author(s):  
Cosmin Safta ◽  
Foluso Ladeinde ◽  
Xiaodan Cai ◽  
Kehinde Alabi
Keyword(s):  
Level Set ◽  
Mixture Fraction ◽  
Reacting Flows ◽  
Turbulent Reacting Flows ◽  
Progress Variable ◽  
Variable Approach ◽  
Partially Premixed

Large-Eddy Simulation of Reacting Turbulent Flows in Complex Geometries

2005 ◽  
Vol 73 (3) ◽  
pp. 374-381 ◽  
Author(s):  
K. Mahesh ◽  
G. Constantinescu ◽  
S. Apte ◽  
G. Iaccarino ◽  
F. Ham ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Reacting Flows ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Variable Approach ◽  
Large Eddy

Large-eddy simulation (LES) has traditionally been restricted to fairly simple geometries. This paper discusses LES of reacting flows in geometries as complex as commercial gas turbine engine combustors. The incompressible algorithm developed by Mahesh et al. (J. Comput. Phys., 2004, 197, 215–240) is extended to the zero Mach number equations with heat release. Chemical reactions are modeled using the flamelet/progress variable approach of Pierce and Moin (J. Fluid Mech., 2004, 504, 73–97). The simulations are validated against experiment for methane-air combustion in a coaxial geometry, and jet-A surrogate/air combustion in a gas-turbine combustor geometry.

scholarly journals A priori investigation of subgrid correlation of mixture fraction and progress variable in partially premixed flames

2018 ◽  
Vol 22 (5) ◽  
pp. 862-882 ◽  
Author(s):  
Zhi X. Chen ◽  
N. Anh Khoa Doan ◽  
Shaohong Ruan ◽  
Ivan Langella ◽  
N. Swaminathan
Keyword(s):  
Mixture Fraction ◽  
A Priori ◽  
Premixed Flames ◽  
Progress Variable ◽  
Partially Premixed Flames ◽  
Partially Premixed

scholarly journals Large Eddy Simulation of Autoignition in a Turbulent Hydrogen Jet Flame Using a Progress Variable Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Rohit Kulkarni ◽  
Wolfgang Polifke
Keyword(s):  
Large Eddy Simulation ◽  
Mixture Fraction ◽  
Chemical Mechanism ◽  
Model Parameters ◽  
Jet Flame ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Variable Approach ◽  
Tabulated Chemistry ◽  
Large Eddy

The potential of a progress variable formulation for predicting autoignition and subsequent kernel development in a nonpremixed jet flame is explored in the LES (Large Eddy Simulation) context. The chemistry is tabulated as a function of mixture fraction and a composite progress variable, which is defined as a combination of an intermediate and a product species. Transport equations are solved for mixture fraction and progress variable. The filtered mean source term for the progress variable is closed using a probability density function of presumed shape for the mixture fraction. Subgrid fluctuations of the progress variable conditioned on the mixture fraction are neglected. A diluted hydrogen jet issuing into a turbulent coflow of preheated air is chosen as a test case. The model predicts ignition lengths and subsequent kernel growth in good agreement with experiment without any adjustment of model parameters. The autoignition length predicted by the model depends noticeably on the chemical mechanism which the tabulated chemistry is based on. Compared to models using detailed chemistry, significant reduction in computational costs can be realized with the progress variable formulation.

Review of Large-Eddy Simulation of Non-Premixed Turbulent Combustion

2004 ◽  
Vol 128 (2) ◽  
pp. 209-215 ◽  
Author(s):  
James J. Riley
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Combustion ◽  
Mixture Fraction ◽  
Reacting Flows ◽  
Turbulent Reacting Flows ◽  
Premixed Turbulent Combustion ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Recent Developments ◽  
Potential Use

Recent developments in the methodology of large-eddy simulation applied to turbulent, reacting flows are reviewed, with specific emphasis on mixture-fraction-based approaches to nonpremixed reactions. Some typical results are presented, and the potential use of the methodology in applications and the future outlook are discussed.

Transient Radiation Properties of a Subgrid Scale Eddy

1992 ◽  
Vol 114 (1) ◽  
pp. 234-242 ◽  
Author(s):  
J. P. Gore ◽  
J. H. Jang
Keyword(s):  
Mixture Fraction ◽  
Reacting Flows ◽  
Radiative Cooling ◽  
Recent Experimental Data ◽  
Turbulent Reacting Flows ◽  
Turbulent Diffusion Flame ◽  
Total Enthalpy ◽  
Time Space ◽  
Transient Simulations ◽  
Cooling Effects

Analysis of transient radiative cooling of a strongly radiating turbulent diffusion flame is described. The specific objective is to study the possibility of including realistic radiative cooling effects in transient simulations of turbulent reacting flows. The laminar flamelet concept is used to estimate all scalar properties other than temperature and density. These are obtained from transient evolutions for total enthalpy in conjunction with the state relationships. The equation is numerically solved in the mixture fraction-time space. Results show aflame structure involving a relatively cold soot layer on the fuel-rich side consistent with recent experimental data.

Premixed Generated Manifolds for the Computation of Technical Combustion Systems

2009 ◽  
Author(s):  
Anja Ketelheun ◽  
Clemens Olbricht ◽  
Frederik Hahn ◽  
Johannes Janicka
Keyword(s):  
Bluff Body ◽  
Mixture Fraction ◽  
Computational Cost ◽  
Statistical Dependence ◽  
Good Prediction ◽  
Flammability Limits ◽  
Reaction Progress ◽  
Progress Variable ◽  
Variable Approach ◽  
Good Prediction Accuracy

Large eddy simulations (LES) show a good prediction accuracy at a decent computational cost for the simulation of combustion processes in complex geometries. However, the large grids required make the direct solution of detailed reaction kinetics impracticable. Therefore, the chemical reactions can be tabulated in a pre-processing step using detailed chemistry with one-dimensional laminar steady flamelets. These flamelets can be either non-premixed or premixed and are stored based on controlling variables like mixture fraction and reaction progress parameter, for example. In this work, a progress variable approach (PVA) using premixed flamelets was adopted to generate a manifold defined by mixture fraction and reaction progress variable. Since the computation of the flamelets is only feasible between flammability limits, the data outside these limits has to be extrapolated to obtain the complete manifold for all chemical states. The extrapolation influences the stability of the LES and its prediction quality and so four different extrapolation schemes were studied. A probability density function (PDF) model was applied to account for subgrid scale variances. Two methods of modeling the joint PDF of mixture fraction and progress variable in terms of their statistical dependence were investigated. Some results of a bluff body configuration comparing the PDF modeling approaches are shown. The results demonstrated that a diffusion flame can be simulated with both the progress variable approach based on premixed flamelets and classic non-premixed flamelets without progress variable.

Recent Advances in Measurement of Turbulent Reacting Flows in Which Heat Transfer is Dominated by Radiation

2010 ◽  
Author(s):  
G. J. Nathan ◽  
P. A. M. Kalt ◽  
Z. T. Alwahabi ◽  
B. B. Dally ◽  
P. R. Medwell ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Mixture Fraction ◽  
Soot Volume Fraction ◽  
Reacting Flows ◽  
Diagnostic Methods ◽  
Practical Significance ◽  
Turbulent Reacting Flows ◽  
Detailed Measurement ◽  
Recent Advances

Recent advances in diagnostic methods are providing new capacity for detailed measurement of turbulent, reacting flows in which heat transfer is dominant. Radiation typically becomes dominant in flames containing soot and/or with sufficient physical size, so is important in many flames of practical significance. The presence of particles, including soot, increases the coupling between the turbulence, chemistry and radiative heat transfer processes. Particles also increase the difficulties of laser-based measurements by increasing the interferences to the signal and the attenuation of the beam. The paper reviews recent advances in techniques to measure temperature, mixture fraction, soot volume fraction, velocity, particle number density and the scattered, absorbed and transmitted components of radiation propagation through particle laden systems.

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