The results of five experimental investigations on the initiation, propagation and transmission of detonation have shown that the wave behavior depends on the relative rates of gasdynamic expansion and chemical energy release occurring within the cellular detonation front. The former rate is controlled by the "boundary conditions" defined by the physical system, while the latter rate depends on the chemical and physical properties of the combustible mixture. The fractional increase (xi) in the area of the post-shock "stream tube", evaluated over a chemical kinetic distance equal to the cell length, has been identified as a parameter which satisfactorily characterizes the competition between these two rate processes. For (xi) less than about 20%, the chemical processes survive the gasdynamic expansion and self-sustained propagation is possible. However, under these "supercritical" conditions, the wave propagates with a velocity deficit which appears to be a universal and theoretically predictable function of (xi). / For (xi) greater than 20%, the shock/reaction zone coupling breaks down, resulting in failure of the wave. The "critical" conditions for the propagation of detonation waves subjects to a wide range of expansion inducing mechanisms, including viscous boundary layers, compressible boundary gases and yielding walls, are all found to be consistent with the 20% criterion. However, the criterion becomes inapplicable as the cell size approaches the characteristic transverse dimension of the geometry. / In the case of direct initiation or transmission of detonation from one geometry to another, the critical conditions are shown to be linked to the requirement for the diverging wave to exceed some minimum radius of curvature. Such radius is geometry dependent and satisfies the stream tube criterion. The role of the "initial conditions" in this type of problem is to guarantee survival of the wave until it achieves the minimum radius for which shock/reaction zone coupling, and hence self-substance, are possible.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 215-232).

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Guensler, Randall; Committee Member: Rodgers, Michael; Committee Member: Russell, Armistead.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 133-137). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Alabama at Birmingham, 2006. / Description based on contents viewed Jan. 29, 2007; title from title screen. Includes bibliographical references (p. 42-44).

The effects of swirl and spark location on combustion duration were studied in a constant volume cylindrical chamber of length-to-diameter ratio of 0.5. A chemically balanced methane-air mixture was swirled up to 628 radians per second by tangential injection. The chamber was closed by a valve before ignition by a spark gap of variable location and electrode geometry. The burning duration, indicated by repeated measurements of combustion pressure rise, was found to be a strong function of swirl intensity and spark location. Increased swirl resulted in decreased burning duration; mid-radius ignition location combined with high swirl resulted in the shortest combustion durations. Spark gap was found to have an important effect on the standard deviation of the burning duration, especially with high swirl. Various "flame holders" were installed to achieve shorter burning durations and lower cyclic variation. Results indicated that the best ignition source geometry was an unshielded, low-drag probe. This gave the least burning durations and the least cyclic variation at the higher swirl values. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Call number: LD2668 .T4 1979 P63 / Master of Science

Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Bibliography: leaves 114-122.

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