Influence of perforated plate thickness on supersonic combustion wave propagation mechanism in a stoichiometric H2-O2 mixture. (1st March 2022) - Guo, Wang
Highlights: Stoichiometric hydrogen-oxygen combustion wave through the perforated plate was studied. Four different modes as the supersonic combustion wave through the perforated plate were discovered. The criteria of a detonation transmitting the perforated plate successfully is d/λ larger than 2.29. Abstract: The behaviors of a supersonic combustion wave through the perforated plate were studied based on velocity and cellular structures. The perforated plate with the thicknesses of Δ = 40 mm, 70 mm, and 100 mm was placed perpendicular to the direction of combustion wave propagation. Stoichiometric hydrogen-oxygen was used in all tests with initial pressure ranging from 11 kPa to 55 kPa. Soot foils were employed to record the triple-point trajectory of a detonation through the perforated plate. Pressure transducers were used to measure the shock time-of-arrival, based on which average velocity was derived. It was found that the fast flame, entering the perforated plate, either maintains fast flame or accelerates to detonation. For CJ detonation, the diffraction kills the detonation directly, and the decoupled detonation may re-initiate or not, which is up to the initial pressure and the geometry of the perforated plate. However, for an overdriven detonation, it can transmit the perforated plate successfully with no failure. The critical condition for a detonation go or no go requires d/λ (d is the hole diameter and λ is the cell size) to be larger than 2.29.