I13 Influence of Energy Spectrum and Scales of Turbulence on Burning Velocity of Spherically Propagating Premixed Turbulent Flame

2011 ◽  
Vol 2011.64 (0) ◽  
pp. 315-316
Author(s):  
Akihiro HAYAKAWA ◽  
Yukito MIKI ◽  
Yukihide NAGANO ◽  
Toshiaki KITAGAWA
Keyword(s):  
Energy Spectrum ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Premixed Turbulent Flame

Numerical Modeling of Stationary But Developing Premixed Turbulent Flames

2006 ◽  
Author(s):  
Pratap Sathiah ◽  
Andrei N. Lipatnikov
Keyword(s):  
Bluff Body ◽  
Burning Velocity ◽  
Rectangular Channel ◽  
Turbulent Flame ◽  
Flame Stabilization ◽  
Turbulent Flames ◽  
Turbulent Diffusivity ◽  
Flame Thickness ◽  
Premixed Turbulent Flames ◽  
Premixed Turbulent Flame

A typical stationary premixed turbulent flame is the developing flame, as indicated by the growth of mean flame thickness with distance from flame-stabilization point. The goal of this work is to assess the importance of modeling flame development for RANS simulations of confined stationary premixed turbulent flames. For this purpose, submodels for developing turbulent diffusivity and developing turbulent burning velocity, which were early suggested by our group (FSC model) and validated for expanding spherical flames [4], have been incorporated into the so-called Zimont model of premixed turbulent combustion and have been implemented into the CFD package Fluent 6.2. The code has been run to simulate a stationary premixed turbulent flame stabilized behind a triangular bluff body in a rectangular channel using both the original and extended models. Results of these simulations show that the mean temperature and velocity fields in the flame are markedly affected by the development of turbulent diffusivity and burning velocity.

A two-eddy theory of premixed turbulent flame propagation

1981 ◽  
Vol 301 (1457) ◽  
pp. 1-25 ◽  
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Experimental Measurements ◽  
Laminar Burning Velocity ◽  
Turbulent Reynolds Number ◽  
Theoretical Predictions ◽  
Premixed Turbulent Flame ◽  
Turbulent Burning Velocity

Available experimental data on the turbulent burning velocity of premixed gases are surveyed. There is discussion of the accuracy of experimental measurements and the means of ascertaining relevant turbulent parameters. Results are presented in the form of the variation of the ratio of turbulent to laminar burning velocities with the ratio of r.m.s. turbulent velocity to laminar burning velocity, for different ranges of turbulent Reynolds number. A two-eddy theory of burning is developed and the theoretical predictions of this approach, as well as those of others, are compared with experimentally measured values.

Further development of the three-region model of a premixed turbulent flame III. Eddy entrainment, combustion in depth process of region 3

1979 ◽  
Vol 368 (1733) ◽  
pp. 295-304 ◽  
Keyword(s):  
Burning Velocity ◽  
Turbulent Flame ◽  
Small Scale ◽  
Laminar Burning Velocity ◽  
Turbulence Scale ◽  
Advection Term ◽  
Region Model ◽  
Premixed Turbulent Flame ◽  
High Level

An experimental study of the turbulent kinetic energy balance for the eddy entrainment, combustion in depth process of region 3 has been carried out. The influence of approach turbulence scale, intensity and laminar burning velocity on each term in the balance equation has been examined for propane-air and acetylene-air flames and the important role of small scale turbulent motion is highlighted. It is observed that either an increase in intensity or a reduction in scale of approach turbulence increases the magnitude of all terms except that for convection. The core region of the flame shows jet-like behaviour. The entrainment, combustion in depth process produces a very high level of fluctuating vorticity. Therefore, the dominant terms appear to be those of viscous dissipation and advection. Finally, a large increase in laminar burning velocity enhances the contribution of the advection term at the expense of a reduction in the convection term.

Further development of the three-region model of a premixed turbulent flame I. Turbulent diffusion dominated region 2

1979 ◽  
Vol 368 (1733) ◽  
pp. 267-282 ◽  
Keyword(s):  
Turbulence Intensity ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Turbulent Energy ◽  
Variable Density ◽  
Turbulent Flames ◽  
Laminar Burning Velocity ◽  
Advection Term ◽  
Set Up ◽  
Premixed Turbulent Flame

A study of the balance equation for turbulent kinetic energy of a premixed turbulent flame has been carried out. Various parameters constituting each term have either been measured or have been calculated from previously measured values. Propane and hydrogen were used as fuels, and the turbulence intensity of the approach flow was varied. Thus, an energy balance of turbulence in a flame has been set up. These results show that increase in both approach turbulence intensity and laminar burning velocity reduce the ratio of production/dissipation in a flame. Thus the stabilizing influence of laminar burning velocity is fully confirmed. The turbulent convection term is found to remain substantially unaltered. The advection term, on the other hand, changes from a loss to a gain in the turbulent energy of the flame. Finally, it is shown that significant differences exist between a flame and a non-reactive variable density axisymmetric jet. These conclusions make the study of turbulent flames unique in that theories that do not accommodate their special features should either be modified or abandoned.

Experimental Study on Local Burning Velocity of Hydrogen added Methane Premixed Turbulent Flame

2004 ◽  
Vol 2004 (0) ◽  
pp. 305-306
Author(s):  
Hiroyuki KIDO ◽  
Masaya NAKAHARA ◽  
Kenshiro NAKASHIMA ◽  
Daisuke MATSUDA ◽  
Hideaki TAKAMOTO
Keyword(s):  
Experimental Study ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Premixed Turbulent Flame ◽  
Local Burning

Further development of the three-region model of a premixed turbulent flame II. Instability dominated region 1

1979 ◽  
Vol 368 (1733) ◽  
pp. 283-293 ◽  
Keyword(s):  
Energy Balance ◽  
Viscous Dissipation ◽  
Balance Equation ◽  
Large Scale ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Flame Structure ◽  
Small Scale ◽  
Laminar Burning Velocity ◽  
Premixed Turbulent Flame

An analysis of the balance equation for turbulent kinetic energy of an instability dominated region 1 is presented for a turbulent, premixed propane-air flame. The effects of intensity, scale and laminar burning velocity on the energy balance are also examined. Specifically, the nature of instability in a turbulent flame and its influence on the flame structure are highlighted. These results show that either increase in scale or reduction in intensity of approach turbulence increases the magnitude of all the terms in the balance equation. The core region of the flame is unaffected by a small scale instability, whereas, for a large scale instability, the ratio of turbulence production/viscous dissipation remains independent of scale. The dominant terms in the energy balance are found to be those of convection and advection when the structure of the flame turbulence consists mainly of a large scale fluctuating motion. Finally, increase in laminar burning velocity restores stability and causes transition to region 2, in which production and viscous dissipation predominate over convection and advection terms, respectively.

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