Research on Two-Phase Flow Instability in Parallel Multi-Channel Under Rolling Motion Condition

Abstract

Two-phase flow instability of the parallel multi-channel system has been studied under rolling motion condition in this paper. Based on the homogeneous flow model with considering the rolling motion condition, the parallel multi-channel model is established by using the control volume integrating method. Gear method is used to solve the system equations. The influences of the inlet and upward sections and the heating power on the flow instability under rolling motion condition have been analyzed. The marginal stability boundary (MSB) under rolling motion condition is obtained and the unstable regions occur in both low and high equilibrium quality regions. The region with low inlet subcooling is also instable. In high equilibrium quality region, the multiplied period phenomenon is found and the chaotic phenomenon appears at the MSB. The oscillation part of mass flow rate (amplitude) may be averaged into other channels so that the influence of rolling motion is weakened. But the stability of multi-channel system is independent of the channel number and the increase of the channel number could only make the amplitude more uniformity in channels.