Theoretical investigations on two-phase flow instability in parallel multichannel system

In this paper, the behavior of multichannel system two-phase flow instability is studied theoretically. A physics model that includes the entrance section, heater section and riser section is built. The subcooled boiling is also included. The results of twin-channel system are compared with the twin-channel experiment. Then the model is extended to the multichannel systems that have more channels. The two-phase flow instability between multichannels (FIBM) is studied under different system pressures, different inlet resistance coefficients and asymmetric heating. The instability boundaries of the multichannel system are obtained in the parameter plane of the subcooling and phase change numbers. A concept of instability space or instability reef is brought forward. Finally, the influence of inlet and riser sections on the FIBM is analyzed.