多台阶通道中的爆震衍射
This research investigated multiple detonation diffraction events in order to betterunderstand the limits and benefits of diffraction strategies with respect to pulsedetonation engine design. Hydrogen/air detonations were generated using sweptramp obstacles in a 1.27 m long channel with a cross section of 25.4 mm by 88.9mm and were diffracted into various multiple-stepped openings. This allowed thedetonation wave diffraction transmission limits to be determined for hydrogen/airmixtures and to better understand reinitiating mechanisms throughout thediffraction process. Tests were conducted for area ratios ranging from 2.00–2.60with varying equivalence ratios from 0.5–1.5.Computational methods were used to better understand the diffractionphenomenon using a series of sensitivity studies for different chemistry sets,computational cell size and equivalence ratio. Experimental tests used combinedoptical shadowgraph and particle image velocimetry imaging systems to provideshock wave detail and velocity information. The images were observed througha newly designed explosive proof optical section and split flow detonationchannel. It was found that area ratios of 2.0 could survive single and doublediffraction events over a range an equivalence ratio range of 0.8 to 1.14 Arearatios of 2.3 survived the primary diffraction event for equivalence ratios nearstoichiometric for the given step length. Detonation diffraction for area ratios of2.6 did not survive the primary diffraction event for any equivalence ratio andwere unable to transmit to a larger combustor.