摘要 :
We have previously reported the experimental discovery of a second shock forming ahead of a radiative shock propagating in Xe. The initial shock is spherical, radiative, with a high Mach number, and it sends a supersonic radiative...
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We have previously reported the experimental discovery of a second shock forming ahead of a radiative shock propagating in Xe. The initial shock is spherical, radiative, with a high Mach number, and it sends a supersonic radiative heat far ahead of itself. The heat wave rapidly slows to a transonic regime and when its Mach number drops to two with respect to the downstream plasma, the heat wave drives a second shock ahead of itself to satisfy mass and momentum conservation in the heat wave reference frame. We now show experimental data from a range of mixtures of Xe and N2, gradually changing the properties of the initial shock and the environment into which the shock moves and radiates (the radiative conductivity and the heat capacity). We have successfully observed second shock formation over the entire range from 100% Xe mass fraction to 100% N2. The formation radius of the second shock as a function of Xe mass fraction is consistent with an analytical estimate.
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摘要 :
The purpose of this work was to develop an experimental apparatus for the study of the initiation of detonation in a gaseous medium as a result of shock compression. The design of the apparatus is described, and results of some pr...
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The purpose of this work was to develop an experimental apparatus for the study of the initiation of detonation in a gaseous medium as a result of shock compression. The design of the apparatus is described, and results of some preliminary experiments are reported. They indicate that the mechanism of the initiation process behind reflected waves in a shock tube is essentially different than that caused by an accelerating flame. (Author)
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摘要 :
Wave structure of marginal detonations, propagated through nitrogen-diluted stoichiometric hydrogen-oxygen mixtures in a 1-3/4 in. by 3/4 in. rectangular tube, is studied by the soot technique and velocity probes. Both weak shocks...
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Wave structure of marginal detonations, propagated through nitrogen-diluted stoichiometric hydrogen-oxygen mixtures in a 1-3/4 in. by 3/4 in. rectangular tube, is studied by the soot technique and velocity probes. Both weak shocks and strong detonations are shown to propagate transversely behind the detonation front. In marginal detonations in rectangular tubes, waves propagate in both lateral directions behind the initial shock. Ordinarily, each wave is the weak reflected shock of a triple shock interaction. Occasionally, however, as the result of a complex shock interaction, a transverse detonation is developed behind the leading shock. This produces a trace in the form of a band on a tube wall that has been previously coated with carbon soot. The width of this band is governed by the induction delay behind the initial shock. By coupling its measurement with velocity data, induction times and temperatures are obtained from self-sustained detonations. (Author)
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