Burning velocity of turbulent premixed flames in a high-pressure environment

The Coherent Flamelet Model (CFM) is applied to symmetric counterflow turbulent premixed flames studied by Kostiuk et al. The flame source term is set proportional to the sum of the mean and turbulent rate of strain while flame quenching is modeled by an additional multiplication factor to the flame source term. The turbulent rate of strain is set proportional to the turbulent intensity to match the correlation for the turbulent burning velocity investigated by Abdel-Gayed et al. The predicted flame position and turbulent flow field coincide well with the experimental observations. The relationship between the Reynolds averaged reaction progress variable and flame density seems to show a wrong trend due to inappropriate modeling of the sink and source term in the transport equation.

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608 Non-Scanning CT Measurement for Instantaneous 3D Distributions of a Local Burning Velocity of Turbulent Premixed Flames with a Flame-Tracking Multi(40)-Lens-Camera

The Proceedings of Conference of Tokai Branch ◽

10.1299/jsmetokai.2008.57.407 ◽

2008 ◽

Vol 2008.57 (0) ◽

pp. 407-408

Author(s):

Sakiko SHIGA ◽

Kei TAKEUCHI ◽

Yojiro ISHINO ◽

Norio OHIWA

Keyword(s):

Burning Velocity ◽

Premixed Flames ◽

Turbulent Premixed Flames ◽

Ct Measurement ◽

Local Burning ◽

Turbulent Premixed

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High-Pressure Combustion Phenomena

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 3 ◽

10.1115/ht2007-32055 ◽

2007 ◽

Author(s):

Hideaki Kobayashi

Keyword(s):

High Pressure ◽

High Temperature ◽

Flame Spread ◽

Burning Velocity ◽

Premixed Flames ◽

Spread Rate ◽

Flame Spread Rate ◽

Droplet Array ◽

Turbulent Burning Velocity ◽

Turbulent Premixed

Two high-pressure combustion phenomena recently observed by the author’s group are reviewed. The first one is the flame spread of a droplet array in the supercritical pressure range of the fuel in microgravity. Microgravity experiments are essential for research on droplet combustion, especially at high pressure, because of the large Grashof number in normal gravity. The flame spread rate for an n-decane droplet array was measured at high pressure, and a fuel-vapor jet was found to be generated due to an imbalance of surface tension of the droplet surface, leading to a higher flame spread rate. The second phenomenon is turbulent premixed combustion at high pressure and high temperature, environmental conditions of which are very close to those in SI engines and premixed-type gas turbine combustors. Information on the flame characteristics in such conditions has been very limited. A high-pressure combustion test facility with a large high-pressure combustion chamber enabled us to stabilize turbulent premixed flames with a high turbulence Reynolds number and to perform flame observations and measurements for extended period using lasers. Turbulent burning velocity was successfully measured and significant effects of intrinsic flame instability on flame structure and turbulent burning velocity at high pressure were revealed. Effects of CO2 dilution on high-pressure and high-temperature premixed flames were also investigated to evaluate the fundamental effects of exhaust gas recirculation (EGR) in practical high-load high-pressure combustors.

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