A. V. Fedorov

Experimental study of the stripping breakup of droplets and jets after their ejection from a liquid surface

This paper presents the results of experiments on the breakup dynamics of droplets and jets moving in a gas medium after their shock-wave ejection from the surface of a liquid and molten metal. Velocities of jets, droplet clouds, and the free surface and the deceleration parameters of droplets and jets in the gas were measured using a heterodyne laser interferometer (photon Doppler velocimetry). The induction period and the droplet sizes after breakup were determined.

Determination of chemical reaction zone parameters, neumann peak parameters, and the state in the Chapman-Jouguet plane in homogeneous and heterogeneous high explosives

Parameters of detonation waves in homogeneous and heterogeneous high explosives are registered. Dependences of the duration of the chemical reaction zone on the critical diameter are obtained. The transition from a stable to an unstable detonation mode in liquid explosives is studied. In these studies, the regime of normal detonation with a stretched shock wave is observed, and the induction period of the thermal explosion is determined.

Determination of parameters of detonation waves in PETN and HMX single crystals

Detonation parameters in PETN and HMX single crystals are experimentally studied. The state parameters at the Chapman-Jouguet point and the parameters of the Neumann spike and chemical reaction zone are obtained. The duration and width of the chemical reaction zone in single crystals are demonstrated to be appreciably greater than in pressed heterogeneous explosives.

Shock Wave Initiation of Mixture Liquid Explosives

We investigated initiation of liquid HE consisting of tetranitromethane (TNM) and nitrobenzene (NB). Smooth stable (when mass of NB<20%) and pulsing unstable detonation wave front was registered (20–50% NB). We registered shock wave, shock compressed explosive (SCE) detonation wave and normal detonation wave for unstable detonation front on different parts of the front. In case of normal and SCE detonation wave we registered parameters rise during 3–25 nsec until the start of chemical reaction. We consider it to be the induction period of thermal explosion inside detonation wave front.

On the stability of the detonation front in tetranitromethane-nitrobenzene and tetranitromethane-nitromethane liquid composite HEs

The stability of the detonation front and the detonation parameters of composite liquid HEs of fueloxidizer type prepared from tetranitromethane, nitrobenzene, and nitromethane are studied using laser interferometry.

Study of Relaxation of Elastic Precursor in Natural Uranium

Laser interferometry was used to investigate elastic precursor relaxation in natural uranium. Samples with the thickness of 0.5–10 mm were loaded by shock wave pulse with the pressure of 13 and 17 GPa. In this particular thickness range elastic precursor amplitude attenuates from 4.72 GPa to 1.44 GPa. The resulting experimental data on elastic precursor attenuation are extrapolated well by the dependence σel=3.4x−0.4. The present paper for the first time cites experimental data for the thickness range of 0.5–2mm. As was shown, elastic precursor attenuates 10 and more times stronger in the aforementioned thickness range as compared to that of 2.. 10 mm. This should be attributed to intensive onset of dislocation, development of defect structure in a material, and energy dissipation.

Recording of Dispersion of Elastic Wave Velocity in Natural Uranium

Laser interferometer techniques were used to research elastic precursor (EP) velocities in natural uranium samples 3–10 mm in thickness. A complicated elastic precursor shape was recorded, which might be explained by the shift and turn of constituent elements of the deformed continuum. The elastic precursor release jitter and velocity dispersion were measured to a spatial resolution of ∼0.1 mm (with respect to different interferometric lines there are recorded different elastic precursor amplitudes and profiles). Microstructure studies of samples after loading showed that average distance between shear bands at elastic precursor are in good agreement with the interferometry measurements.

Study of Detonation Wave Structure in Solid and Liquid Tetranitromethane (TNM)

Investigations of detonation front structure and parameters in solid and liquid tetranitromethane were done using Doppler Fabry‐Perot velocimeter. We recorded the particle velocity of explosion products, braking on the HE/window interface. Smooth front of the detonation wave and concave negative‐going particle velocity profile were recorded for liquid TNM. The experimental records indicate that because of solid TNM heterogeneity flow, turbulization occurs behind detonation wave front what appears in the form of velocity fluctuations on the U(t) profile.

Characterization of Optically Transparent Window Materials for Isentropic‐Compression Studies

Experimental researches were made to determine change of refractive index of transparent materials PMMA and LiF under quasi‐isentropic loading. Laser interferometric velocimeter Fabry‐Perot was changed as the method of investigation. Values of the correction factor Κ=1+Δv/v and the refractive indexes n were obtained for the given loading conditions. The obtained experimental data under the quasiisentropic loading in PMMA and LiF was compared with the same under the shock‐wave compression.