Influence of turbulent flowing condition on the ignition of flammable fuel/air-mixtures

摘要

In the present work,spark-induced ignition of methane/air- and starch/air-mixtures under turbulent conditios is investigated in a pipe-flow under increased turbulence by the use of grids.For the characterization of the turbulence in the test facility a laser doppler anemometer had been used and to determine the real energy released by the spark ignition source,current and voltage during the spark discharge were measured.The results show,that mainly the turbulent fluctuations influence the ignition process whereas the convective part of the flow (up to velocities of 40 m/s) has only little influence.For numeericla work a 1-dimensional simulation program,that includes detailed chemistry and multi-species transport was used.It is shown that the main influence on the ignition process is due to the rms-value.Furthermore the influence of increased flow velocity on flammability limits,different spark duration times and different macrolength on the ignition process are demonstrated.