An imploding annular shock wave driven by a jet of air was used to initiate detonations inside a 76 mm diameter tube. The tube was filled with a test gas composed of either stoichiometric ethylene-oxygen or propane-oxygen diluted with nitrogen. The strength of the imploding shock wave and the sensitivity of the test gas were varied in an effort to find the minimum shock strength required for de...

The accurate determination of the speed of a propagating disturbance is important for a number of applications. A nonstationary cross-spectral density phase technique was developed to provide a statistical estimation for the propagation time, and was applied to a shock and a detonation wave. The results show that by including an envelope signal, the technique is an improvement over the traditio...

Abstract To study the axial distribution rules of initial velocity and direction angle prefabricated fragments, first, acceleration process fragments is divided into three stages:"detonation wave stage”,"metal medium interaction stage” “detonation product stage”, to establish three-stage detonation drive model based on energy conservation, correction coefficients in were subsequently fitted usi...

The possibility of using a detonation wave as the key combustion system for supersonic propulsion is examined. A brief review of propagating detonations is provided first. This review emphasizes the unique and unstable nature of the coupling between reaction zone and shock waves that characterize detonations. The theory of idealized, steady, oblique detonation waves and their reaction zone stru...

The numerical approximation of combustion processes may lead to numerical difficulties, which are caused by different time scales of the transport part and the reactive part of the model equations. Here we consider a modified fractional step method that overcomes this difficulty on standard test problems and allows the use of a mesh width and time step determined by the nonreactive part, withou...

The Numerical modeling of burning particles, initiated from a heavily aluminized High Explosive (HE) is being investigated. Reactive multiphase flows must be modeled to properly account for variable-size aluminum particles burning behind the blast wave. The governing equations also include models for solid evaporation and chemical reactions. The final paper will present comparison of experiment...

A long plasma channel, formed due to the dynamic balance between the nonlinear self-focusing and the plasma defocusing in the propagation of intense femtosecond laser pulses in air, is demonstrated to be able to continuously propel a paper airplane without complicated focusing optics. The maximum coupling coefficient generated by the plasma channel is found to be more than 8.5 dyne/W. In the pl...

D ETONATION, a shock-induced combustion process in which the heat releasemakes a strong contribution to the support of the lead shock, is one of the most rapid chemical energy release processes in nature. For self-sustained detonations propagating in gases initially at atmospheric pressure and temperature, energy release rates approaching 10 W=m are not uncommon, and propagation velocities on t...

For the ignition of a thermonuclear detonation wave assisted by a strong magnetic field, it is proposed to use two concentrically nested magnetically insulated transmission lines, the inner one transmitting a highvoltage lower-current-, and the outer one a high-current lower-voltageelectromagnetic pulse drawn from two Marx generators. The concept has the potential of large thermonuclear gains w...