ID#: 207
Abstract Title: Numerical Investigation of Transverse Wave Structures in Two-Dimensional H2-O2-Diluent Detonations
Session Title: Cellular Structure I
Session Date: 7/30/01
Session Start Time: 8:55 AM
Contributing Author: Inaba, K.
Organization: Keio University
Country: Japan
Authors: Kazuaki Inaba, Akiko Matsuo, Katsumi Tanaka
Short Abstract: Two-dimensional computations of the propagating detonations in the mixture of 2H2+O2+3.76N2/3.76Ar at initial pressures 1.00, 0.421, and 0.132 atm were performed using a detailed chemical reaction mechanism. The transverse wave strength was defined as the dimensionless pressure increase across the reflected shock and was determined for the different channel widths. When a detonation propagates through a narrow channel in all cases, the shock structure evolves from a single Mach structure to a double Mach structure. In H2-Air at 1.00 and 0.421 atm, the transverse wave strength increases up to 1.5 with increasing the channel width, and the shock configuration evolves from the single Mach structure to a complex Mach structure. Both in H2-Air at 0.132 atm and H2-O2-Ar at 1.00 atm, the transverse wave strength does not go beyond 0.85, but the flow features show the complex Mach structure. In H2-O2-Ar at 0.132 atm, the transverse wave evolves up to the double Mach structure and the transverse wave strength indicated 0.5. Although the complex Mach structure appears, except for the case of H2-O2-Ar at 0.132 atm, the strong transverse detonations occurs only in H2-Air at 1.00 and 0.421 atm. We pursuit the lowest post-shock pressure and temperature and recognize that only the conditions of H2-Air at 1.00 and 0.421 atm varies across the second explosion limit. Therefore we summarize that the strong transverse detonation occurs due to the change in post-shock properties, which results in the immediately increase of the induction length and the onset of the strong transverse detonation.