Characterization of the ignition by repetitive streamer discharges using laser diagnostics

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• 作者：Detlef Markus ; ^{Detlef.Markus@ptb.de} ; Aljoscha Hallermann ; Michael Paul ; Tim Langer ; Frank Lienesch
• 关键词：Ignition ; Electrical discharges ; Laser-induced fluorescence
• 刊名：Journal of Loss Prevention in the Process Industries
• 出版年：2013
• 出版时间：March, 2013
• 年：2013
• 卷：26
• 期：2
• 页码：324-328
• 全文大小：613 K

文摘

Repetitive streamer discharges caused by transients, e.g. due to high frequency overvoltages, can ignite combustible mixtures, which has to be taken into account concerning the safety assessment of electrical apparatus for usage in hazardous areas. Hydrogen/air mixtures were ignited inside a closed vessel using a rod/plane electrode configuration. Alternating voltage with a frequency between 600 and 750?kHz and amplitudes of up to 20?kV was used to produce streamer discharges. The ignition process and the subsequent flame front propagation were examined with respect to mixture composition and several electrical parameters using time-resolved measurements of planar laser-induced fluorescence (PLIF) of OH radicals. A multiple pulse laser and detection system was used to assemble four images during one experiment. These measurements have given detailed information about the point of ignition and flame velocities. The experimental results will be used to validate numerical simulations of ignition by streamer discharges, which will yield deep insights into this specific ignition process.