Browsing by Subject "streamers"

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    Simulating mode transitions during breakdown in liquids
    (IEEE, 2011-06) Murphy, B.T.; Hebner, R.E.; Kelley, E.F.
    The primary new information from this investigation is the simulation of a transition from one streamer mode to another during propagation. The transition is characteristic of experimental data, but has not heretofore been described in a model. This demonstrates that the conceptual framework describing prebreakdown streamers in liquids as stochastic growth of a branching fractal tree in point-plane geometry is capable of simulating a wide range of streamer propagation behaviors in insulating liquids. The work also improved the approach in the model for scaling the potential at nearby grid points and explored some of the influences of computational choices, specifically needle length and grid size, on the predicted results.
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    Stochastic Modeling of Streamer Transitions
    (IEEE, 2008-10) Kim, M.; Murphy, B.; Hebner, R.E.
    Simulations of the growth of streamers using a model based on the stochastic growth of a branching fractal tree have shown good fidelity in matching the morphology of streamers in liquids. An important aspect that has not yet been simulated is the transition between Type 1 and Type 2 streamers. This work explores the effect of a variation of the applied voltage during streamer growth as well as the effect of differing amounts of available electrons during growth. Neither of these assumptions produced the experimentally observed transitions. These results produced a possible approach that could modify the step length in the simulation in relation to the electric field that may trigger the transition. It also points out that the transition might be due to hydrodynamic instabilities that are not captured by the model.