Laser ignition and flame characteristics of pulsed methane jets in homogeneous isotropic turbulence without mean flow
| Autor: | Gyungmin Choi, Yonmo Sung, Yannis Hardalupas, Georgios Charalampous |
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| Rok vydání: | 2016 |
| Předmět: |
Technology
Engineering Chemical Laser ignition Energy & Fuels Homogeneous and isotropic turbulence General Chemical Engineering Pulsed jet 0904 Chemical Engineering Mechanical engineering 0902 Automotive Engineering Physics::Fluid Dynamics ENERGY symbols.namesake COMBUSTION Engineering PREMIXED FLAMES Mean flow Physical and Theoretical Chemistry Physics::Chemical Physics Jet (fluid) Homogeneous isotropic turbulence Science & Technology Chemistry Turbulence INDUCED SPARK-IGNITION Mechanical Engineering Diffusion flame DISTRIBUTED REGIMES Reynolds number AIR MIXTURES Engineering Mechanical DIFFUSION FLAMES Minimum ignition energy Physical Sciences Chemical Engineering(all) symbols Thermodynamics Atomic physics TRANSITION 0913 Mechanical Engineering |
| Popis: | The influence of turbulence on the minimum ignition energy (MIE) and ignited flame characteristics is investigated for pulsed methane diffusion jets ignited by laser-induced plasma. The methane jet is injected in a volume of homogeneous and isotropic air turbulence without mean flow, with the level of turbulence being controlled independently. The study is carried out for a range of fuel jet ( Re jet ) Reynolds number, namely 1000, 2000, and 3000, and a range of turbulent ( Re λ ) Reynolds number, namely 0–207. The results show that the position of the maximum intensity of flame emission was randomly scattered due to the fact that the ignited flame is deflected from the nozzle axis by the turbulent velocity fluctuations. The effect is more profound at higher Re jet . The value of the MIE, determined according to 50% ignitibility of mixture, increases by a factor of 2 for an increase of Re λ from 0 to 207 and by a factor of 5 for an increase of Re jet from 1000 to 3000. Two trends are observed on MIE with Re λ . For low Re λ , MIE is independent of Re λ . Past a critical value of Re λ , MIE increases as a linear function of Re λ . This transition occurs at critical values of Re λ,c = 158, 197 and 202 for Re jet = 1000, 2000 and 3000, respectively. The mean value of MIE for ignition before and after transition is a linear function of Re jet . The difference between the mean value of MIE before transition and after transition is around 5 mJ for all considered Re jet . |
| Databáze: | OpenAIRE |
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