Flow in a pressurized, vapor condensation boron nitride nanotube production rig is modeled. A laser provides a thermal energy source to the tip of a boron fiber bundle in a high-pressure nitrogen chamber causing a plume of boron-rich gas to rise. The buoyancy-driven flow is modeled as a mixture of thermally perfect gases (B, B 2 , N, N 2 , BN) in either thermochemical equilibrium or chemical nonequilibrium, assuming steady-state melt and vaporization from a 1 mm radius spot at the axis of an axisymmetric chamber. The simulation is intended to define the macroscopic thermochemical environment from which boron-rich species, including nanotubes, condense out of the plume. Simulations indicate a high-temperature environment ( T > 4400 K ) for elevated pressures within 1 mm of the surface, sufficient to dissociate molecular nitrogen and form BN at the base of the plume. Modifications to the program LAURA, a finite volume-based solver for hypersonic flows including coupled radiation and ablation, are described to enable this simulation. High-pressure synthesis conditions enable formation of BN vapor in the plume, which may serve to enhance formation of exceptionally long nanotubes in the pressurized vapor condensation process.


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    Title :

    Laser Vaporization and Plume Chemistry in a Boron Nitride Nanotube Production Rig


    Contributors:

    Published in:

    Publication date :

    2013-07-01




    Type of media :

    Conference paper , Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English