Ejection of Particles from the Free Surface of Shock-Loaded Lead into Vacuum and Gas Medium
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Ejection of Particles from the Free Surface of Shock-Loaded Lead into Vacuum and Gas Medium V. A. Ogorodnikova,b, A. L. Mikhailova,b, S. V. Erunova, M. V. Antipova, A. V. Fedorova, M. A. Syrunina,b, E. V. Kulakova,*, O. A. Kleshchevnikova, I. V. Yurtova, A. A. Utenkova, S. A. Finyushina, E. A. Chudakova, D. A. Kalashnikova, A. S. Pupkova, A. V. Chapaeva, A. V. Mishanova, V. V. Glushikhina, A. V. Fedoseevb, R. R. Tagirova, S. A. Kostyukova, I. Yu. Tagirovaa, and E. V. Saprykinaa a All-Russia
Research Institute of Experimental Physics, Russian Federal Nuclear Center, Sarov, Nizhny Novgorod oblast, 607188 Russia b Sarov State Institute of Physics and Technology, Branch of the National Nuclear Research University MEPhI (Moscow Engineering Physics Institute), Sarov, Nizhny Novgorod oblast, 607188 Russia *e-mail: [email protected] Received April 16, 2017
Abstract—The presence and behavior of a gas–metal interfacial layer at the free surface of shock-wave driven flying vehicles in gases of various compositions and densities has not been sufficiently studied so far. We present new comparative data on “dusting” from the free surface of lead into vacuum and gas as dependent on the surface roughness, pressure amplitude at the shock-wave front, and phase state of the material. Methods of estimating the mass flux of ejected particles in the presence of a gas medium at the free metal surface are proposed. DOI: 10.1134/S1063776117120172
The phenomenon of shock-wave induced “dusting” or ejection of particles from the free surface (FS) of a material loaded by a shock wave (SW) has been experimentally studied over a long time, especially thoroughly in recent years [1–15]. This process has also been numerically simulated using a Richtmeyer– Meshkov solution describing small sinusoidal disturbances of the FS under the action of stationary or nonstationary SW incident onto a liquid or elastoplastic material [12, 14]. According to the results of these investigations, dominating factors determining the mechanism of particle ejection are the surface roughness and phase state of the material (solid or liquid). In particular, SW incident onto the FS with microscopic roughness caused, e.g., by metal cutting process, induces cavitation of the walls of microgrooves left by the tool. This results in the formation of microjets separating into fragments (particles) due to the gradient of velocity in the direction of motion and the finite strength of material. The sizes of particles are related to the dimensions and geometry of surface roughness (micrgrooves). Depending on the phase state of material (solid or liquid), velocities of particles, and parameters of the gas medium, coarse particles can divide into smaller fragments. It should be noted that more detailed information available on the source of “dust-
ing” is related to the FS roughness and material structure, defects, and phase state (solid or liquid), rather than to other factors influencing this process, in particular, the presence of gas medium at the FS and the
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