Study on the Effects of Pressure on Turbulent Burning Velocity of Outwardly Propagating Propane-Air Flame with Turbulence Reynolds and Markstein Numbers

Kitagawa, Toshiaki; Nagano, Yukihide; Tsuneyoshi, Kousaku

doi:10.1299/kikaib.72.825

Cited by 4 publications

(3 citation statements)

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“…This trend is similar to the premixed methane/air flame [43] and premixed hydrogen/air flame [44]. On the other hand, the premixed iso-octane/air flame [18] and premixed propane/air flame [45] displayed an opposite trend. The value of the Markstein number for = 0.8 and 0.9 is negative.…”

Section: Resultssupporting

confidence: 74%

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Extinction limits of an ammonia/air flame propagating in a turbulent field

Ichimura

Hadi

Hashimoto

et al. 2019

Fuel

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Ammonia, which does not emit carbon dioxide even when it is burned, is expected as a new carbon-free fuel to replace coal and natural gas used in thermal power plant. However, the turbulent flame propagation characteristics have yet to be extensively investigated. This study aimed to clarify the extinction limits of ammonia/air flame in turbulent fields. To achieve this aim, the spherical flame propagation experiments using a fan-stirred constant volume vessel were conducted.The results revealed the unique feature of extinction limit of ammonia in a turbulent field. The ammonia/air mixture with a 0.9 equivalence ratio can propagate at the highest turbulence intensity even though the laminar burning velocity reaches a maximum around an equivalence ratio of 1.1. The fuel-lean mixture can propagate at high turbulence intensity because of the effect of Lewis number. For a lean ammonia/air mixture that has a Lewis number smaller than unity, the local burning velocity increases by the diffusional-thermal instability. On the other hand, the local burning velocity in rich ammonia/air mixtures with a Lewis number larger than unity did not increase in the turbulent field, and the flame was easily extinguished. Because of the diffusional-thermal instability, the turbulence Karlovitz number at the flame extinction limit increases as the Markstein number decreases. The obtained findings from this study can contribute to the optimal design of gas turbines fueled by ammonia as well as the safety use of ammonia.

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Section: Resultssupporting

confidence: 74%

“…The turbulence Karlovitz number at each condition was obtained by Eq. ( 13) as a characteristic value of the flame stretch given to the turbulent flame by the turbulent flow [45]:…”

Section: Discussion On Extinction Limitsmentioning

confidence: 99%

Extinction limits of an ammonia/air flame propagating in a turbulent field

Ichimura

Hadi

Hashimoto

et al. 2019

Fuel

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“…Recent studies by Kitawaga et al (8), (19) have discussed the influence of Markstein length on turbulent flames for propane and methane. In this study, an equivalence ratio of 0.4 yielded a negative Markstein length.…”

Section: Turbulent Flamesmentioning

confidence: 99%

Turbulent and Stable/Unstable Laminar Burning Velocity Measurements from Outwardly Propagating Spherical Hydrogen-Air Flames at Elevated Pressures

Smallbone

Tsuneyoshi

Kitagawa

2006

JTST

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The laminar burning velocity of pre-mixed hydrogen-air mixtures was measured in a fan stirred combustion bomb. Unstretched laminar burning velocities and Markstein lengths were obtained at 0.10MPa for equivalence ratios of 0.4, 0.6, 0.8 and 1.0 using high speed flame imaging. The difficulties which arose whilst obtaining similar measurements at 0.25MPa and 0.50MPa are outlined. The turbulent burning velocity was measured at equivalence ratios of 0.4 and 0.8 from explosions carried out at 0.10MPa with turbulence intensities of 0.8 and 1.6m/s. Higher turbulent burning velocity ratios were observed for mixtures which yielded lower Markstein lengths in the laminar combustion experiments.

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