Experimental studies on flame propagation and quenching characteristics of premixed N2O and fuels in reduced–diameter channels

This study established a reduced-diameter combustion channel system to investigate combustion characteristics, detonation flame quenching, and attenuation using N 2 O and fuel mixtures. High-speed Schlieren photography was used to track the flame evolution in polymethyl methacrylate channels, allowing for subsequent calculation of flame front speeds. The results revealed two primary flame behaviors: flame quenching and flame passage. Flame passage was characterized by successful flame propagation, whereas quenched flames failed to pass through the capillary. The required quenching channel diameters for N 2 O/C 2 H 4 , N 2 O/C 3 H 8 , and N 2 O/NH 3 were 0.2–0.3, 0.5–0.7, and 1.2–1.6 mm, respectively. Furthermore, with increasing capillary length and flame speed, the critical diameter for flame quenching decreased. These findings offer valuable insights into the failure modes of fire-extinguishing processes and may aid in improving the fire-resistance performance of flame arresters.