Flame propagation and auto-ignition of n-C₇H₁₆ / air premixture in high temperature / pressure closed vessel

In this study, the auto-ignition and flame propagation under high temperature and pressure conditions are experimentally investigated. n-C7H16/air mixture is ignited by electric spark at the center of a constant volume vessel of 20-mm inner diameter and 80-mm long under various conditions of temperature (400-500K) and pressure (0.5-1.0MPa), and the flame propagation and auto-ignition behavior near the closed end are observed. In the experiment, distinct end-gas auto-ignition occurs at 500K and 1.0MPa, accompanied by the propagation of both cool and hot flames in the end-gas region. Following the end-gas auto-ignition, amplification of the pressure wave by acoustic resonance is observed, indicating that the propagation and reflections of the pressure wave within the chamber govern the maximum pressure attained.