LAUSR

Abstract Two phase flow instability is of vital importance to the safety of nuclear reactors and other boiling systems. In this work, a theoretical model for the two phase flow instability in parallel channels in ocean motions is developed based on drift flux model. The effect of phasic slip effect is considered. The variation of density against temperature and enthalpy is included. The theoretical results are validated with experimental data and pioneer research results with a satisfactory agreement obtained. The effects of several important parameters on the stability boundary are also analyzed. It is found that the effect of rolling motion on the stability boundary in parallel channels is limited in motions with small accelerations. The effect of heeling motion on the stability boundary of parallel channels is slight. In rolling motion, the stable region in parallel channels decreases as the channel distance increasing, which is caused by the increasing of rolling radius and additional forces. This work is valuable for the subsequent research of small modular reactors.