Numerical Simulation of Two-Phase Flow Behavior under Earthquake Acceleration

Fluctuation of void faction is an important factor for the safety operation of the nuclear reactor, and fluctuation of void fraction is related to behavior of gas-liquid two-phase flow. In case of the earthquake, the fluctuation is not only the flow rate, but also body force on the two-phase flow and shear force through a pipe wall. Interactions of gas and liquid through their interface also act on the behavior of the two-phase flow. The fluctuation of the void fraction is not clear for such complicated situation under the earthquake. Therefore, the behavior of gas-liquid two-phase flow is investigated experimentally and numerically in a series of study. In this study, to develop the prediction technology of two-phase flow dynamics under earthquake acceleration, a detailed two-phase flow simulation code with an advanced interface tracking method TPFIT was expanded to two-phase flow simulation under earthquake conditions. The bubbly flow in a horizontal pipe excited by oscillation acceleration and under the fluctuation of the liquid flow was simulated by using the expanded TPFIT. And the influence of acceleration, the fluctuation of flow rate and the fluctuation of share force though a pipe wall were investigated in the numerical simulations.