A Model of Liquid Metal Droplet Vaporization in Arc Heated Gas Streams

A model of simultaneous heat and mass transfer has been constructed to describe vaporization of liquid metal droplets in arc heated gas streams. The major assumptions of the model include 1) plug flow, 2) negligible pressure drop, 3) no droplet-droplet interactions, 4) negligible gas radiation, natural convection, thermal diffusion, diffusion-thermo transport and axial conduction and diffusion, and 5) no interfacial discontinuities in temperature or concentration. The latter assumption is discussed in detail in a separate appendix. The analysis is limited to binary, nonreacting gas mixtures. The mathematical formulation results in five nonlinear, first order differential equations with temperature and compositional dependent properties. The model is applied to the vaporization of sodium and magnesium droplets injected into arc heated argon flowing in a cylindrical reactor. The effect of parameters such as initial droplet radius, reactor diameter, and liquid metal flowrate on the reactor length required to achieve a specified degree of vaporization is calculated.