|M.Sc Student||Gilburd Leonid|
|Subject||Underwater Electrical Explosion of Modified Wire Array|
|Department||Department of Physics||Supervisors||Professor Yakov Krasik|
|Professor Emeritus Joshua Felsteiner|
|Full Thesis text|
The present thesis is devoted to research of extreme water parameters created by a converging strong shock wave generated by underwater electrical wire array explosion.
The main purposes of the research were modifications of the cylindrical wire array which should allow one to obtain increased values of water density, temperature and pressure in the vicinity of the implosion axis without additional increase in the energy stored by the pulsed generator. Because of the difficulty to make a direct measurement of the water parameters, numerical hydro-dynamic simulation coupled with equations of state data bases and experimental data were implemented.
The experiments were carried out using a pulsed current generator charged to 80kV, with stored energy and current rise time of 6.14 kJ and 350 ns, respectively. The experimental results, coupled with modified hydro-dynamic simulation have shown that the application of an outer reflector made of material with significantly higher density than water density can result in a more efficient energy transfer to the converging water flow. The latter leads to an increase in the water pressure, density, temperature and internal energy in the vicinity of the implosion axis. It is shown that in the case of a Cu wire array (5 mm in diameter), the application of the outer metal reflector increases the pressure, density, and temperature of the water in the vicinity of the implosion axis ~1.38, ~1.07 and ~1.33 times, respectively. Moreover, in order to optimize the energy transfer to the converging water flow, we investigated the influence of the reflector material and its radial distance with respect to the wire array on the water parameters in the vicinity of the implosion axis.
The experimental and simulation results showed that the application of Al wire array allows one to obtain significantly higher water density, temperature and pressure in the vicinity of the implosion axis. This is caused by combustion of Al wires following by deposition of the additional energy into the converging water flow. It was shown that the application of Al wire array with a stainless steel reflector results in Al combustion and generates ~540 GPa pressure in the vicinity of the explosion axis.
As an example of application, it was shown in this research the ability of underwater electrical wire explosion to ignite different Al powder suspensions and to show that additional energy could be achieved from the process of chemical combustion of Al micro-particles.