Posted by: Citrus Marketing | February 3, 2013

Next Up! Riccardo Bonazza, PhD of the UW Engineering Department

Science Pub, February 10 @2pm @Brocach on Main Street, Madison

Please join us in welcoming Professor Riccardo Bonazza, PhD as our next Science Pub Speaker. Dr. Bonazza is an expert in shockwaves and all sorts of other incredibly smart topics about which this web writer would like to learn.

Riccardo’s topic will be Shock-Bubbles. Shock waves sometimes propagate through non-homogenous materials. In doing so, they cause the materials to move in complicated ways, and if more than one material components are present, the propagation of of the shock wave causes them to mix into each other. Examples of these events include the explosion of the cores of a certain class of stars called supernovae and the setup for one of these approaches suggested for the achievement of controlled nuclear fusion. Riccardo’s group performs experiments where a shock wave strikes a bubble full of glass initially moving freely inside a different gas. While no nuclear reaction occurs in the experiments, our results are useful in understanding the mixing process between the two gasses.

Here’s a summary from his web page:

Fields of Interest

  • experimental fluid mechanics and heat transfer
  • impulsive unsteady phenomena
  • shock tube applications
  • laser and X-ray imaging & measuring techniques

Summary

Professor Bonazza’s interests are in the areas of instrumentation and associated diagnostics as needed in the experimental investigation of impulsive, unsteady fluid flows such as shock-interface interactions and vapor explosion phenomena.The interaction of a shock wave with the interface between two fluids of different densities enhances the mixing that takes place at the interface. In some cases the mixing is detrimental to the objectives pursued in the application. In inertial-confinement nuclear fusion experiments, eg, a spherical, hollow shell containing a deuterium-tritium mixture is imploded by the shock wave generated by ten laser beams focused on it. The objective is to raise the temperature and density of the nuclear fuel to obtain a self-sustained fusion process. Upon acceleration, the shell’s manufacturing imperfections amplify causing the ablated shell material to mix with the fuel thus causing the end of the fusion process. In supersonic combustion systems, where fast, thorough mixing between fuel and oxidizer is indispensable to effective burning because of the very short residence time of the oxidizer in the chamber, shock-enhanced mixing could be used advantageously. The interaction of a shock with a fluid interface is investigated experimentally in a vertical, square shock-tube, using non-intrusive, optical diagnostics techniques.The study of vapor explosions is related to the development of an industrial waste-processing technique in which a water solution of toxic organic compounds is injected into a pool of molten iron, to use the thermal shock and the catalytic action of the iron to chemically crack down the toxic compounds into their harmless components. The mechanisms of explosive vaporization, and the thermophysical conditions under which a mechanical explosion takes place are investigated. In a cryogenic simulation experiment, the interaction of hot water with different types of refrigerant is investigated, using a light-extinction technique. In another experiment, water is injected into a pool of molten tin and the system is imaged with a continuous X-ray source and digital imaging system.

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