每年專案

## 摘要

In 2014, Wu et al. discovered an unexpected result. Turbulence can facilitate ignition through differential diffusion when the effective Lewis number (Le) of mixtures is sufficiently larger than unity using small electrode gaps (d_{gap} ≤ 0.8 mm) in near-isotropic turbulence generated by a fan-stirred burner. This suggested that the required minimum ignition energy (MIE) in intense turbulence can be smaller than that in quiescence (Wu et al. did not measure MIE). This work explores whether the aforesaid turbulent facilitated ignition (TFI) for Le > 1 is independent of d_{gap}. We apply the same hydrogen mixtures at the equivalence ratio ϕ = 5.1 (Le ≈ 2.3) and ϕ = 0.18 (Le ≈ 0.3) as Wu et al. in our large fan-stirred cruciform bomb capable of generating near-isotropic turbulence to measure values of MIE as a function of d_{gap} at both quiescence and intense turbulence (the rms turbulent fluctuating velocity u′ = 5.4 m/s) conditions. A drastic fall of values of laminar and turbulent MIE (MIE_{L} and MIE_{T}) with increasing d_{gap} is observed. TFI only occurs for Le > 1 (ϕ = 5.1) and it is restricted at smaller d_{gap} = 0.58 mm, where MIE_{L} = 61.5 mJ >> MIE_{T} = 26 mJ (0.25-mm tungsten electrodes) and MIE_{L} = 255.5 mJ >> MIE_{T} = 36.8 mJ (2-mm tungsten electrodes) in support of Wu et al.’s finding. However, we discover that the MIE_{L} and MIE_{T} curves versus d_{gap} can cross each other at larger d_{gap}, at which no TFI for Le > 1 at d_{gap} = 2 mm where MIE_{L} = 0.52 mJ << MIE_{T} = 17.3 mJ (2-mm tungsten electrodes). This interesting result depending on d_{gap} should be disseminated in our combustion community for stimulating further research.

原文 | ???core.languages.en_GB??? |
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頁（從 - 到） | 1-3 |

頁數 | 3 |

期刊 | Combustion and Flame |

卷 | 185 |

DOIs | |

出版狀態 | 已出版 - 2017 |

## 指紋

深入研究「Is turbulent facilitated ignition through differential diffusion independent of spark gap?」主題。共同形成了獨特的指紋。## 專案

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