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This content will become publicly available on February 1, 2026

Title: Simultaneous Schlieren and direct photography of detonation diffraction regimes in hydrogen mixtures
The diffraction behavior of gaseous detonations through an abrupt area change is investigated using hydrogen-oxygen-nitrogen mixtures at initial pressures of 0.5 and 1.0 bar. Critical conditions are noted and detailed discussion of the differing diffraction behaviors is undertaken, supported by simultaneous Schlieren and direct photography imaging as well as pressure-based velocity measurements. The experiments reveal four distinct diffraction regimes. The subcritical outcome is characterized by transmission failure with the leading shock front decoupling from the reaction zone, seen predominantly at lower oxygen concentrations. At intermediate oxygen levels, reinitiation from reflected shock waves is consistently observed. The critical regime exhibits both subcritical and supercritical outcomes, with detonation reinitiation at the diffraction dome's head leading to localized implosions for the supercritical case. Supercritical outcomes demonstrate successful detonation transmission, maintaining the shock front and reaction zone coupling. The effects of initial conditions on the probability of successful detonation transition and diffraction are highlighted. With the use of simultaneous direct photography and Schlieren imaging techniques, previously unseen details of the detonation and diffraction processes are recorded and explained.  more » « less
Award ID(s):
2324471
PAR ID:
10621254
Author(s) / Creator(s):
;
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Combustion and Flame
Volume:
272
Issue:
C
ISSN:
0010-2180
Page Range / eLocation ID:
113845
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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