ZHANG Wenchao, JIAO Qi, ZHOU Yunlong, et al. Visualization study on pressure drop and superimposed oscillations under low pressure natural circulation in rectangular channel[J]. CIESC Journal, 2018, (6): 2455-2462.
ZHANG Wenchao, JIAO Qi, ZHOU Yunlong, et al. Visualization study on pressure drop and superimposed oscillations under low pressure natural circulation in rectangular channel[J]. CIESC Journal, 2018, (6): 2455-2462.DOI: 10.11949/j.issn.0438-1157.20171302.
visualization technique was used to study pressure drop and superimposed oscillations of low pressure natural circulation in rectangular channel. Gas-phase distribution images captured during oscillation processes were compared with flow pulsation curve to assess physical process and mechanism of flow oscillation. Four types of dynamic instabilities were found in the study
i.e.
density wave oscillation by gravity (DWOⅠ)
pressure drop oscillation (PDO)
superimposed oscillation (SPO)
and density wave oscillation by friction (DWOⅡ). Due to squeezing effect of rectangular channel and compressible space limitation within surge tank
working fluid flew cyclically between surge tank and circulation circuit and generated pressure drop oscillation (PDO). With increase of heating power
superimposed oscillation was formed by overlapping PDO and DWOⅡ. The onset points of both oscillations tended to diverge with increase of inlet overcooling degree
and such diverging tendency enlarged when system pressure was increased. DPO instability boundary curve was plotted against dimensionless parameters