Numerical Simulations of Dynamics of Premixed Hydrogen-Air Flames Propagating in Ducts

Xiao, Huahua

doi:10.1007/978-3-662-48379-4_3

Cited by 1 publication

(1 citation statement)

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“…The longer the pipe is, the farther the tulip flame propagates. Combined with the formation of tulip flame, vortex of different scales is also formed behind the flame, 26 , 27 which increases the turbulence intensity in the flow field and causes laminar flow transforming to turbulent flow. Therefore, the longer distance the tulip flame propagates in the open-ended pipe, the larger the turbulent kinetic energy is, and eventually the flame speed is accelerated.…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation of the influence of pipe length on explosion flame propagation in open-ended and close-ended pipes

Zhou

Liu

et al. 2020

Science Progress

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The pipeline length exerts great influence on flame propagation characteristics, Realizable [Formula: see text] model and Premixed combustion model were used to study the influence of pipe length on propane-air explosion flame in open-ended and close-ended pipes. Using the numerical model verified by experiments, the changes of flame structure and flame propagation speed are studied. The result showed that the Realizable model was in good agreement with the experimental results. It also proved that the reflected wave produced a strong interference on the flame front, which promoted the formation of tulip flame. Besides, some obvious vortices were usually generated in the burned gas after the tulip flame formed, which will affect the flow field around the flame front and thus exert influence on the flame structure. The formation mechanism of tulip flame as well as the flame self-acceleration is different in open-ended and close-ended pipes. In close-ended pipes, the reflection wave at the pipe end and the reflection-induced countercurrent both promote the formation of tulip flame. As the flame propagates to the pipe end, the flame propagation is inhibited by the compression wave formed by the rapid expansion of combustion products under high temperature. While, in open-ended pipes, the turbulence induced by the opening at the pipe end is the main cause of tulip flame formation. The flame acceleration depends on the combustion reaction of unburned gas, so the velocity of flame propagation continues to increase. Generally, the maximum flame propagation velocity in the open-ended pipe is larger than that in the close-ended pipe.

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Section: Resultsmentioning

confidence: 99%