Interrelationship of the baric index for the normal burning velocity of gas?Air mixtures and the kinetics of trimolecular reactions in a flame front

1991 ◽  
Vol 27 (2) ◽  
pp. 173-175
Author(s):  
Yu. N. Shebeko ◽  
A. Ya. Korol'chenko ◽  
V. G. Shamonin ◽  
S. G. Tsarichenko
Keyword(s):  
Flame Front ◽  
Burning Velocity ◽  
Kinetics Of ◽  
Normal Burning Velocity

The Time Required for Constant-Volume Combustion

1952 ◽  
Vol 19 (1) ◽  
pp. 72-76
Author(s):  
A. S. Campbell
Keyword(s):  
Temperature Distribution ◽  
Flame Front ◽  
Thermodynamic Analysis ◽  
Burning Velocity ◽  
Combustion Process ◽  
Constant Volume ◽  
Time Rate ◽  
Constant Volume Combustion ◽  
Time Required ◽  
Normal Burning Velocity

Abstract By combining the results of an elementary thermodynamic analysis of the temperature distribution in the burned gases of a constant-volume bomb with an examination of the velocity relations at the flame front, it is possible to relate the “normal burning velocity” to the time rate of production of burned gases. Integration of this equation leads to an estimate of the time required for the combustion process.

scholarly journals Prediction of Deflagrative Explosions in Variety of Closed Vessels

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2138
Author(s):  
Wojciech Rudy ◽  
Andrzej Pekalski ◽  
Dmitriy Makarov ◽  
Andrzej Teodorczyk ◽  
Vladimir Molkov
Keyword(s):  
Flame Front ◽  
Burning Velocity ◽  
Premixed Flame ◽  
Combustion Mechanism ◽  
Velocity Dependence ◽  
Laminar Burning Velocity ◽  
Transient Pressure ◽  
Predictive Capability ◽  
Preferential Diffusion ◽  
Insight Into

In this paper the multi-phenomena deflagration model is used to simulate deflagrative combustion of several fuel–air mixtures in various scale closed vessels. The experimental transient pressure of methane–air, ethane–air, and propane–air deflagrations in vessels of volume 0.02 m3, 1 m3, and 6 m3 were simulated. The model includes key mechanisms affecting propagation of premixed flame front: the dependence of laminar burning velocity of concentration, pressure, and temperature; the effect of preferential diffusion in the corrugated flame front or leading point concept; turbulence generated by flame front itself or Karlovitz turbulence; increase of the flame front area with flame radius by fractals; and turbulence in the unburned mixture. Laminar velocity dependence on concentration, pressure, and temperature were calculated using CANTERA software. Various scale and geometry of used vessels induces various combustion mechanism. Simulations allow insight into the dominating mechanism. The model demonstrated an acceptable predictive capability for a variety of fuels and vessel sizes.

Effects of Hydrogen Addition on Swirl-Stabilized Flame Properties

2010 ◽  
Author(s):  
Shengrong Zhu ◽  
Sumanta Acharya
Keyword(s):  
Flame Front ◽  
Surface Density ◽  
Recirculation Zone ◽  
Burning Velocity ◽  
Mie Scattering ◽  
Reacting Flow ◽  
Flame Surface ◽  
Flame Surface Density ◽  
Hydrogen Addition ◽  
Methane Flame

The role of hydrogen addition to swirl-stabilized methane flames is studied experimentally. Of specific interest are flame properties including flame surface density and curvature. The measurements are based on Particle Image Velocimetry (PIV), Mie-scattering and CH-chemiluminescence imaging. Identification of the flame front and its geometric characterization provides an understanding of the flame properties. Compared to the non-reacting flow, the methane flame broadens the central recirculation zone. Hydrogen enriched flames reduce the central recirculation zone and scales down the characteristic length of the flow. With hydrogen addition, the distribution of the flame front curvature is broadened and flame surface density is increased. This indicates that hydrogen addition increases the reaction front thermo-diffusive instability, causing the flame front to be more wrinkled, and increasing the flame surface area leading to an increase in the burning velocity.

Transient and limit cycle combustion dynamics analysis of turbulent premixed swirling flames

2017 ◽  
Vol 830 ◽  
pp. 681-707 ◽  
Author(s):  
Paul Palies ◽  
Milos Ilak ◽  
Robert Cheng
Keyword(s):  
Heat Release ◽  
Flame Front ◽  
Limit Cycle ◽  
Burning Velocity ◽  
Propagation Mode ◽  
Dynamic Mode ◽  
Flame Surface ◽  
Swirl Number ◽  
Combustion Dynamics ◽  
Swirling Flames

Premixed low swirling flames (methane–air and hydrogen–methane–air) are experimentally investigated for three different regimes. Stable, local transient to instability and limit cycle regimes corresponding to three distinct equivalence ratios are considered. Dynamic mode decomposition is applied to the hydrogen–air–methane flame to retrieve the modes frequencies, growth rates and spatial distributions for each regime. The results indicate that a vortical wave propagating along the flame front is associated with the transition from stability to instability. In addition, it is shown that a key effect on stability is the location of the non-oscillating (0 Hz) flame component. The phase-averaged unsteady motion of the flames over one cycle of oscillation shows the vortical wave rolling up the flame front. The Rayleigh index maps are formed to identify the region of driving and damping of the self-sustained oscillation, while the flame transfer function phase leads to the propagation mode of the perturbations along the flame front. The second mechanism identified concerns the swirl number fluctuation induced by the mode conversion. By utilizing hypotheses for the flow field and the flame structure, it is pointed out that those mechanisms are at work for both flames (methane–air and hydrogen–methane–air) and their effects on the unsteady heat release are determined. Both unsteady heat release contributions, the vortical wave induces flame surface fluctuations and swirl number oscillation induces unsteady turbulent burning velocity, are in phase opposition and of similar amplitudes.

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