Numerical study on the spark ignition characteristics of hydrogen–air mixture using detailed chemical kinetics

Hydrogen is a promising fuel and is expected to replace hydrocarbon fuels for its significant potentials to reduce the pollutants and greenhouse gases. It is very important to investigate Minimum ignition energy (MIE) on safety standards and ignition process of hydrogen–air mixtures. Even though the formation of flame kernels in quiescent hydrogen–air mixtures has been researched numerically and experimentally, the details of ignition mechanism have never been satisfactorily explained. In this study, the spark ignition of hydrogen–air mixture is investigated by using detailed chemical kinetics and considering the heat loss to the electrode. The purpose of this study is emphasized in the effects of the energy supply procedure, the radius of the spark channel, electrode size and electrode gap distance on the MIE. In addition, the effects of mixture temperature, electrode gap distance and electrode size on relationship between the equivalence ratio and the MIE are examined.

► The hydrogen–air spark ignition was investigated using detailed chemical kinetics. ► The energy supply procedure dramatically affected the MIE for hydrogen. ► As spark channel radius decreased to 0.15 mm, the MIE leveled off near 0.04 mJ. ► The electrode size significantly affected the MIE within the quenching distance.