Thermohydraulics in liquid metals

Heat transfer problems in single-phase and two-phase liquid metal forced convection flow are reviewed. Liquid metal boiling heat transfer in pool flow; and dry out heat fluxes are considered. It is shown that in technological plants working with liquid metals, superheating up to 150 C occurs, and can lead to nonstationary hydraulic transition between the single-phase and established two-phase flows. Boiling phases relative to subcooled boiling and bubble boiling have no importance for technological processes. Piston, slug and annular flow patterns dominate. On the basis of the flow patterns observed during boiling, the separate flow model principle is the only one suitable for calculating the two-phase flow pressure drop. Using this model and total pressure drop measurements, a relationship for the two-phase frictional pressure characteristic, valid for tubular and annular geometry, can be determined.