scholarly journals Study on Burning Velocity of Premixed Turbulent Flames with Wrinkled Laminar Flame Structure. Behavior of Vibrating Flames and Flame Propagation Model.

1995 ◽  
Vol 61 (586) ◽  
pp. 2283-2289
Author(s):  
Tetsui Yanagi ◽  
Noboru Kagawa
Keyword(s):  
Flame Propagation ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Flame Structure ◽  
Turbulent Flames ◽  
Propagation Model ◽  
Premixed Turbulent Flames

The structure and propagation of turbulent flames

1975 ◽  
Vol 344 (1637) ◽  
pp. 217-234 ◽  
Keyword(s):  
Turbulence Intensity ◽  
Combustion Zone ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Turbulent Flame ◽  
Flame Structure ◽  
Turbulent Flames ◽  
Flame Speed ◽  
Turbulence Scale ◽  
Turbulent Flame Speed

The influence of turbulence intensity, scale and vorticity on burning velocity and flame structure is examined by using premixed propane-air mixtures supplied at atmospheric pressure to a combustion chamber 31cm long and lOcmx 10 cm cross-section. The chamber is fitted with transparent side walls to permit flame observations and schlieren photography. Control over the turbulence level is achieved by means of grids located upstream of the combustion zone. By suitable modifications to grid geometry and flow velocity, it is possible to vary turbulence intensity and scale independently within the combustion zone in such a manner that their separate effects on burning velocity and flame structure are readily distinguished. From analysis of the results obtained three distinct regions may be identified, each having different characteristics in regard to the effect of scale on turbulent burning velocity. For each region a mechanism of turbulent flame propagation is proposed which describes the separate influences on burning velocity of turbulence intensity, turbulence scale, laminar flame speed and flame thickness. The arguments presented in support of this 3-region model are substantiated by the experimental data and by the pictorial evidence on flame structure provided by the schlieren photographs. This model also sheds light on some of the characteristics which turbulent flames have in common with laminar flames when the latter are subjected to pressure and velocity fluctuations. Finally the important role of vorticity is examined and it is found that turbulent flame speed is highest when the rate of production of vorticity is equal to about half the rate of viscous dissipation.

scholarly journals Effect of Stretch on Local Burning Velocity of Premixed Turbulent Flames

2007 ◽  
Vol 2 (2) ◽  
pp. 268-280 ◽  
Author(s):  
Masaya NAKAHARA ◽  
Hiroyuki KIDO ◽  
Takamori SHIRASUNA ◽  
Koichi HIRATA
Keyword(s):  
Burning Velocity ◽  
Turbulent Flames ◽  
Premixed Turbulent Flames ◽  
Local Burning

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.

scholarly journals Laminar flame speed of soy and canola biofuels

2012 ◽  
Vol 4 (5) ◽  
pp. 75-83 ◽  
Author(s):  
Juan-Sebastián Gómez-Meyer ◽  
Subramanyam R Gollahalli ◽  
Ramkumar N. Parthasarathy ◽  
Jabid-Eduardo Quiroga
Keyword(s):  
Flame Propagation ◽  
Equivalence Ratio ◽  
Laminar Flame ◽  
Turbulent Flames ◽  
Flame Speed ◽  
Thermochemical Property ◽  
Laminar Flame Speed ◽  
Hot Air ◽  
Maximum Value ◽  
Canola Oils

In this article, the flame speed values determined experimentally for laminar premixed flames of the vapors of two biofuels in air are presented. The laminar flame speed is a fundamental thermochemical property of fuels, and is essential for analyzing the flame propagation in practical devices, even those employing turbulent flames. The fuels obtained from transesterification of soy and canola oils are tested. Also, the diesel flames are studied to serve as a baseline for comparison. The experiments are performed with a tubular burner; pre-vaporized fuel is mixed with hot air and is ignited. The flame speed is determined at fuel-equivalence ratios of 1; 1,1 and 1,2 by recording the geometry of the flame. The experimental results show that the flame speed of biofuels is lower by about 15% than that of diesel. Also, the maximum value of flame speed is obtained at an equivalence ratio of approximately 1,1.

412 Influence of Markstein Number on Local Burning Velocity of Premixed Turbulent Flames

2005 ◽  
Vol 2005.58 (0) ◽  
pp. 145-146
Author(s):  
Masaya NAKAHARA ◽  
Hiroyuki KIDO ◽  
Kenshiro NAKASHIMA ◽  
Hideaki TAKAMOTO ◽  
Koichi HIRATA
Keyword(s):  
Burning Velocity ◽  
Turbulent Flames ◽  
Premixed Turbulent Flames ◽  
Markstein Number ◽  
Local Burning

A Model for Flame Propagation in Low Volatile Coal Dust-Air Mixtures

1978 ◽  
Vol 100 (1) ◽  
pp. 105-111 ◽  
Author(s):  
J. L. Krazinski ◽  
R. O. Buckius ◽  
H. Krier
Keyword(s):  
Flame Propagation ◽  
Energy Transport ◽  
Laminar Flame ◽  
Solid Phase ◽  
Coal Dust ◽  
Flame Structure ◽  
Radiant Energy ◽  
Differential Approximation ◽  
Two Phase ◽  
Coal Particles

A model describing steady, laminar flame propagation in low volatile coal dust-air mixtures is presented. The model includes radiative transport, a two-phase energy equation, and heterogeneous carbon gasification of the coal particles. The differential approximation (or method of spherical harmonics) was used to represent the one-dimensional radiant energy transport. The equations were numerically integrated and predictions of flame structure and the adiabatic flame speed are presented. The effects of radiation properties and coal particle size are presented and discussed. The influence on the temperature profiles of heat released in the solid phase is also described.

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