Abstract
In the millisecond time domain, deflagration curves of the methane, CH4, have been observed at low and elevated initial temperatures. 20-L closed spherical chamber have been adopted for low and high initial temperatures measurements. Methane air mixtures were studied experimentally and numerically for different equivalence ratios between 0.2 and 2.5 and initial temperatures of -20, -10, 0, 10, 20, 30, 40, 50 °C. More than three hundred pressure-time curves were recorded. Twenty-five deflagration curves of the CH4 have been observed in the below-zero temperature region in 20-L volume for the first time, including two pressure-time curves in -20 °C. The effects of temperature on the maximum explosion pressure, maximum rate of pressure rise, and deflagration index were investigated. The evaluated experiments' actual results are the maximum pressure rise rate for -20 °C. Our results should also provide critical information applicable to thermodynamic and kinetic modeling of methane explosion and flame low-temperature chemistry. This work allowed a systematic comparison of the structural and bonding properties among the CnH2n analogs in the physics and chemistry of low temperatures explosions.
