Spark ignition of hydrogen-air mixture

The electrostatic ignition of hydrogen-air mixture is investigated. First, the minimum ignition energy (MIE) of the hydrogen-air mixture is measured using a capacitance spark discharge. The influences of the spark gap length, humidity, and the spark pulse duration on the MIE are studied. It is shown that the MIE is approximately constant when the relative humidity increases from 0% to 90% at room temperature, and that the MIE is approximately constant when the spark duration is varied from 5 ns to 1 ms. Next, the density of OH radicals and gas temperature in an incipient spark-ignited hydrogen(50%)-air flame are measured using laser-induced predissociation fluorescence (LIPF). The time evolutions of the OH density and the gas temperature are measured from 3 mu s to 200 mu s after ignition.