Dynamic Simulations of Pressure-Drop Type Instabilities in a Two-Phase Upflow Boiling System Including the Effect of Thermal Non-Equilibrium

Abstract

The two-phase flow pressure-drop type instabilities in a two-phase upflow boiling system has been studied theoretically. A mathematical model of the exit restriction is presented, which is based on the modified separated flow model in conjunction with the homogeneous flow model of the two-phase fluid flowing through a sharp-edged orifice. The drift-flux model is adopted for prediction. The dynamic oscillations of the quasi-static pressure-drop type instabilities in the boiling system are simulated, and good predictions of the system stability boundary and oscillations characteristics are obtained.