Dependence of turbulent burning velocity on turbulent reynolds number and ratio of flaminar burning velocity to R.M.S. turbulent velocity

1977 ◽  
Vol 16 (1) ◽  
pp. 1725-1735 ◽  
Author(s):  
Ramzy G. Abdel-Gayed ◽  
Derek Bradley
Keyword(s):  
Reynolds Number ◽  
Burning Velocity ◽  
Turbulent Velocity ◽  
Turbulent Reynolds Number ◽  
Turbulent 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.

Turbulent burning velocities: a general correlation in terms of straining rates

1987 ◽  
Vol 414 (1847) ◽  
pp. 389-413 ◽  
Keyword(s):  
Burning Velocity ◽  
Significant Proportion ◽  
Spectral Density Function ◽  
Turbulent Velocity ◽  
Gasoline Engines ◽  
Turbulent Spectrum ◽  
Experimental Values ◽  
Dimensionless Correlations ◽  
Turbulent Burning Velocity ◽  
Lower Frequencies

All known experimental values of turbulent burning velocity have been scrutinized. These number 1650, a significant proportion of which at the higher turbulent Reynolds numbers we measured in a fan-stirred bomb. Dimensionless correlations which have a theoretical basis are presented. These are in terms of flame straining rates and the effective r. m. s. turbulent velocity, as well as the laminar burning velocity of the mixture. When a flame develops from an ignition source it is not initially exposed to the lower frequencies of the turbulent spectrum. As the kernel grows the flame is affected by ever-lower frequencies and the turbulent burning velocity increases towards a fully developed value. An experimental dimensionless power spectral density function is presented, and used to show how both effective r. m. s. turbulent velocity and flame straining rate develop in an explosion. The results are relevant to a variety of practical devices, including gasoline engines, as well as atmospheric explosions.

scholarly journals Effects of Turbulent Reynolds Number on the Performance of Algebraic Flame Surface Density Models for Large Eddy Simulation in the Thin Reaction Zones Regime: A Direct Numerical Simulation Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mohit Katragadda ◽  
Nilanjan Chakraborty ◽  
R. S. Cant
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Fractal Dimension ◽  
Direct Numerical Simulation ◽  
Surface Density ◽  
Flame Surface ◽  
Algebraic Models ◽  
Flame Surface Density ◽  
Turbulent Reynolds Number ◽  
Reaction Zones

A direct numerical simulation (DNS) database of freely propagating statistically planar turbulent premixed flames with a range of different turbulent Reynolds numbers has been used to assess the performance of algebraic flame surface density (FSD) models based on a fractal representation of the flame wrinkling factor. The turbulent Reynolds number Rethas been varied by modifying the Karlovitz number Ka and the Damköhler number Da independently of each other in such a way that the flames remain within the thin reaction zones regime. It has been found that the turbulent Reynolds number and the Karlovitz number both have a significant influence on the fractal dimension, which is found to increase with increasing Retand Ka before reaching an asymptotic value for large values of Retand Ka. A parameterisation of the fractal dimension is presented in which the effects of the Reynolds and the Karlovitz numbers are explicitly taken into account. By contrast, the inner cut-off scale normalised by the Zel’dovich flame thicknessηi/δzdoes not exhibit any significant dependence on Retfor the cases considered here. The performance of several algebraic FSD models has been assessed based on various criteria. Most of the algebraic models show a deterioration in performance with increasing the LES filter width.

scholarly journals Feasibility study of power generation using a turbine mounted in aircraft wing

2018 ◽  
Vol 7 (2-1) ◽  
pp. 433
Author(s):  
K. Sri Vamsi Krishna ◽  
Shiva Prasad ◽  
R. Sabari Vihar ◽  
K. Babitha ◽  
K Veeranjaneyulu ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Power Systems ◽  
Free Stream ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Aircraft Wing ◽  
Aerodynamic Efficiency ◽  
Turbulent Reynolds Number ◽  
Main Motive ◽  
Emergency Power

The main objective of this study is to increase the aerodynamic efficiency of turbine mounted novel wing. The main motive behind this work is to reduce the drag by attaining the positive velocity gradient and generate power by converting the stagnation pressure which also acts as emergency power source. By using the energy source of free stream air, Mechanical energy is converted into electrical energy. The obtained power is presented in terms of voltage generated at various angles of attack with different Reynolds number. Experimental analysis is carried out for NACA4415 airfoil at various angles with respect to free stream ranging from 0deg to 30deg from laminar to turbulent Reynolds number. The results were obtained using the research tunnel at IARE aerodynamic facility center. The aerodynamic advantage of this design in terms of voltage is 9.5 V at 35m/s which can be utilized for the aircraft on board power systems.

A Model for Predicting Turbulent Burning Velocity by using Karlovitz Number and Markstein Number under EGR Conditions

2021 ◽  
Author(s):  
Kei Yoshimura ◽  
Kohei Ozawa ◽  
Kyohei Yamaguchi ◽  
Ratnak Sok ◽  
Jin Kusaka ◽  
...  
Keyword(s):  
Burning Velocity ◽  
Markstein Number ◽  
Turbulent Burning Velocity

scholarly journals Effects of Turbulent Reynolds Number on the Displacement Speed Statistics in the Thin Reaction Zones Regime of Turbulent Premixed Combustion

2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
Nilanjan Chakraborty ◽  
Markus Klein ◽  
R. S. Cant
Keyword(s):  
Reynolds Number ◽  
Strain Rate ◽  
Surface Density ◽  
Three Dimensional ◽  
Flame Surface ◽  
Tangential Strain ◽  
Turbulent Reynolds Number ◽  
Qualitative Nature ◽  
Displacement Speed ◽  
Turbulent Premixed

The effects of turbulent Reynolds number on the statistical behaviour of the displacement speed have been studied using three-dimensional Direct Numerical Simulation of statistically planar turbulent premixed flames. The probability of finding negative values of the displacement speed is found to increase with increasing turbulent Reynolds number when the Damköhler number is held constant. It has been shown that the statistical behaviour of the Surface Density Function, and its strain rate and curvature dependence, plays a key role in determining the response of the different components of displacement speed. Increasing the turbulent Reynolds number is shown to reduce the strength of the correlations between tangential strain rate and dilatation rate with curvature, although the qualitative nature of the correlations remains unaffected. The dependence of displacement speed on strain rate and curvature is found to weaken with increasing turbulent Reynolds number when either Damköhler or Karlovitz number is held constant, but the qualitative nature of the correlation remains unaltered. The implications of turbulent Reynolds number effects in the context of Flame Surface Density (FSD) modelling have also been addressed, with emphasis on the influence of displacement speed on the curvature and propagation terms in the FSD balance equation.

The Effects of Turbulent Burning Velocity Models in a Swirl-Stabilized Lean Premixed Combustor

2018 ◽  
Vol 35 (4) ◽  
pp. 365-372
Author(s):  
Jong-Chan Kim ◽  
Won-Chul Jung ◽  
Ji-Seok Hong ◽  
Hong-Gye Sung
Keyword(s):  
Burning Velocity ◽  
Premixed Combustion ◽  
Dynamic Mode Decomposition ◽  
Combustion Model ◽  
Dynamic Mode ◽  
Turbulent Premixed Combustion ◽  
Velocity Models ◽  
Flame Structures ◽  
Turbulent Burning Velocity ◽  
Turbulent Premixed

Abstract The effects of turbulent burning velocities in a turbulent premixed combustion simulation with a G-equation are investigated using the 3D LES technique. Two turbulent burning velocity models – Kobayashi model, which takes into account the burning velocity pressure effect, and the Pitsch model, which considers the flame regions on the premixed flame structure – are implemented. An LM6000 combustor is employed to validate the turbulent premixed combustion model. The results show that the flame structures in front of the injector have different shapes in each model because of the different turbulent burning velocities. These different flame structures induce changes in the entire combustor flow field, including in the recirculation zone. The dynamic mode decomposition (DMD) method and linear acoustic analysis provide the dominant acoustic mode.

scholarly journals Turbulent burning velocity measurements: Extended to extreme levels of turbulence

2017 ◽  
Vol 36 (2) ◽  
pp. 1801-1808 ◽  
Author(s):  
Timothy M. Wabel ◽  
Aaron W. Skiba ◽  
James F. Driscoll
Keyword(s):  
Burning Velocity ◽  
Velocity Measurements ◽  
Turbulent Burning Velocity
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