The role of electrodes in the spark ignition process

The problem of flame propagation through a gas which is ignited by an electrical discharge is investigated numerically, taking into account the influence of the electrodes. It is shown that critical ignition conditions may exist. A variation in the interelectrode gap produces a change in the developing flame geometry. The extinguishing gap effect, which is observable during a narrowing of the interelectrode gap, is explained by the amplification of the heat exchange with the electrodes.