Experimental Studies on Hugoniot Data of Methane-Air Mixtures under Shock Compression

To study the state parameters of methane-air mixture under shock compression, Aluminum target chamber filled with methane-air mixture were impacted by tungsten alloy projectiles. Projectiles were accelerated to about 5 km/s using a two-stage light gas gun. Methane-air mixture with different air ratioes of 0, 1%, 5%, and 10% were tested, respectively. The radiance signals from shocked methane-air gases were recorded by an instantaneous pyrometer system. The Hugoniot data of four mixed ratio gases were obtained. The experimental results indicated that the shock temperatures of mixtures increase with rising of the air mixed ratio. The mixtures emitted non-equilibrium thermal radiation in shock downstream. The ionization of methane-air gas with 10% air mixed ratio is calculated by Saha ionization function. Calculated results indicated that methane-air mixed gases with an air mixed ratio less than 10% doesn't ionize, and can protect pins effectively.