Performance of a Multiphase Boiling MHD Generator

Abstract

Adiabatic liquid metal-water MHD generators produce power during water boiling because both temperature and pressure drop throughout the phase change. Therefore, boiling MHD generators with boiling water, as distinguished from purely expansive steam-liquid metal MHD generators, may be useful energy-conversion devices. A generator, with a working fluid consisting of a liquid-metal eutectic of tin and bismuth, water, and steam, was analyzed in accordance with anticipated isentropic efficiencies. Real-gas-law data from steam tables were employed to integrate one-dimensional multiphase thermodynamic equations by using Simpson’s rule. Consistency checks on the boiling section showed errors of about 1 percent. The contribution of the boiling section of the generator was computed to be about 20 percent greater per unit length and 360 percent greater per unit volume than the purely expansive section of the MHD generator for the studied inlet conditions.