Spark Ignition Characteristics of Hydrogen Under Ar-O₂ Atmosphere

The hydrogen-fueled argon power cycle engine has the potential for high efficiency and zero emissions. Based on constant volume combustion bomb and capacitive spark ignition system, this paper compares hydrogen spark ignition characteristics under different atmospheres, including breakdown voltage and spark ignition energy. It is expected to provide a theoretical basis for designing spark ignition system in terms of reliable spark ignition and eliminating the backfire or pre-ignition caused by the residual energy in the spark ignition system. Research results indicate that the breakdown voltage and spark ignition energy are highest under the CO₂-O₂ atmosphere, intermediate under the air atmosphere, and lowest under the Ar-O₂ atmosphere. When the initial pressure is 0.1 MPa, the breakdown voltage and spark ignition energy under the 79%Ar-21%O₂ atmosphere are respectively 2533 V and 64 μJ, respectively 24% and 38% lower than those under the air atmosphere. When initial pressure is 0.3 MPa, with the argon proportion increased from 79 to 88%, the breakdown voltage and spark ignition energy increase respectively by 23% and 49% to 5360 V and 282 μJ. Further researches find that the breakdown voltage and spark ignition energy generally increase with the increasing excess oxygen ratio and the decreasing hydrogen proportion. As the gas density increases with the increasing initial pressure, the breakdown voltage and spark ignition energy increase significantly.