EMHD effects on subcooled boiling in a vertical annulus

In this study, the simulation of a steady-state water vapor-water liquid system heated in a vertical annulus with an upward flow under electromagnetohydrodynamics (EMHD) is performed. The annulus is partially heated with the inlet condition of subcooling near saturation. To model the subcooled boiling heat transfer of axial flow the assumptions of nonhomogeneous properties, nonswirling flow, and nonequilibrium between phases is used. Governing equations including the conservation of mass, momentum, and energy are solved by the finite-volume method in axial dimension. The mass transfer is considered in mass conservation; the gravity and EMHD force in momentum conservation; and the viscous dissipation, Joule heating, and radiation are included in the energy conservation. Comparison of area-averaged gas fraction along the axial direction with experimental results showed the accuracy of the numerical modeling. It was seen that the EMHD can decrease the phase transfer rate, and change the velocity difference between phases, volume forces, and dissipation terms. Also the friction factor and Joule heating were augmented by the EMHD forces. © 2018 by Begell House, Inc.