Interaction Of Detonation Wave Research Articles

The Random Projection Method for Stiff Detonation Capturing

In this paper we present a simple and robust random projection method for underresolved numerical simulation of stiff detonation waves in chemically reacting flows. This method is based on the random projection method proposed by the authors for general hyperbolic systems with stiff reaction terms [W. Bao and S. Jin, J. Comput. Phys., 163 (2000), pp. 216--248], where the ignition temperature is randomized in a suitable domain. It is simplified using the equations of instantaneous reaction and then extended to handle the interactions of detonations. Extensive numerical experiments, including interaction of detonation waves, and in two dimensions, demonstrate the reliability and robustness of this novel method.

Development of a Two-Dimensional Hydrogen Detonation Analysis Code Devised to Reduce the Numerical Diffusion

Evaluation of thermal and mechanical loads on the containment vessel due to combustion of flammable gases is essential for addressing the important issues of safety analyses of nuclear power reactors under hypothesized severe accident conditions. In order to predict flammable gas detonation which is the most severe type of combustion, a two-dimensional numerial analysis code COMA has been developed using the explicit finite volume method and non-staggered mesh scheme. A new numerically stable transport calculation method has been devised to facilitate treatment of a large pressure discontinuity at the wave front with the minimum numerical diffusion. The test calculation of detonation propagation in a square cavity surrounded by walls showed that the calculated propagation velocity agreed well with the theoretical velocity by Chapman and Jouguet, and the wave reflection at rigid walls and interaction of detonation waves could be analyzed. The method was then validated through a comparison study with the hydrogen detonation tests in a cylindrical tube performed by NUPEC and BNL. The calculated results agreed with observed overall effects of hydrogen concentration and initial temperature on detonation wave propagation velocities.

Development of a Two-Dimensional Hydrogen Detonation Analysis Code Devised to Reduce the Numerical Diffusion

Evaluation of thermal and mechanical loads on the containment vessel due to combustion of flammable gases is essential for addressing the important issues of safety analyses of nuclear power reactors under hypothesized severe accident conditions. In order to predict flammable gas detonation which is the most severe type of combustion, a two-dimensional numerial analysis code COMA has been developed using the explicit finite volume method and non-staggered mesh scheme. A new numerically stable transport calculation method has been devised to facilitate treatment of a large pressure discontinuity at the wave front with the minimum numerical diffusion. The test calculation of detonation propagation in a square cavity surrounded by walls showed that the calculated propagation velocity agreed well with the theoretical velocity by Chapman and Jouguet, and the wave reflection at rigid walls and interaction of detonation waves could be analyzed. The method was then validated through a comparison study with the hy...

Elimination of jets formed by the interaction of detonation waves

We have considered the phenomenon of collision of detonation waves on the surfaces of aluminum and copper casings. It is shown that a cumulative jet is formed in the first case and a combination of cumulative and “three-shock” jets in the second. Experimentally checked methods of eliminating such jets are proposed.

Zig-Zag Oscilloscope Presentation of Millimicrosecond Accuracy for Microsecond Time Intervals

In the study of metal-high explosive detonation wave interaction, by the pin technique, it is desirable to obtain time measurements to an accuracy of less than 1 mμsec over a total time interval of 5 μsec. Commercial instruments capable of a high degree of time resolution were not available and a special instrument was developed for this purpose. A cathode-ray oscilloscope, displaying deflection type event pulses, is converted into a precise time-measuring instrument by a calibrated zig-zag sweep. The record is obtained by single-shot photography of the cathode-ray tube sweep which is triggered by the event to be measured. The calibrated zig-zag sweep is crystal controlled at 2 Mc and has superimposed deflection type time marks, 2 mμsec wide, at 50-mμsec interval, synchronized with the zig-zag frequency. The apparatus can drive six oscilloscopes simultaneously or in sequence from delayed triggers.