Study on the influence of premixed volume on methane explosion dynamics under semi-confined conditions

Abstract

Gas explosion accidents are highly destructive, and the gas dispersion range significantly affects the explosion intensity. This study combines experiments and simulations in a semi - enclosed pipe to explore how different premixed volumes affect methane - air explosion dynamics and energy release efficiency. Results show that as the premixed volume increases, the average flame propagation velocity rises linearly, the time for the flame front to reach its farthest distance increases, and the peak explosion overpressure changes logarithmically. Expansion waves from the opening create negative pressure inside the pipe, gathering residual flammable gases. This allows unreacted fuel to mix with air again and participate in the explosion, providing energy for multi - peak fluctuations in explosion pressure. At 10vol% conditions, the explosion energy release coefficient correlates positively with the premixed volume. This research offers a theoretical basis for assessing gas explosion accidents and predicting losses.