Flow dynamics and microparticles acceleration in the electrothermal launcher

Application of electrothermal launchers for obtaining powder materials coatings with improved values of density and adhesion requires formation of the gas flow region, immediately following behind the shock wave, where microparticles are being caught into acceleration. A method of such region forming by means of the shock wave space and time shaping is presented. The flow dynamics analysis on the basis of a numerical model, which was carried out for the case of two gaps in the launcher discharge unit, has shown that it is possible to accelerate microparticles up to very high velocities (2 km/s and higher) with simultaneous control of their temperature and to increase substantially the launcher efficiency. Measurements with the experimental equipment allowed us to determine dynamic parameters of flows, the velocity and extension of the shock-compressed region as well as velocities of the shock-waves and main flow region. Registration of plasma flows radiation spectra permitted determination of their temperature. The obtained experimental results are in good correlation with computer simulation data.