摘要

In supercritical water reactor (SCWR), the flow instability phenomenon may occur due to the drastic decrease in the density of supercritical water. Such phenomenon should be detected, prevented and suppressed to ensure the safety of SCWR. In this work, a one-dimensional transient model for predicting the occurrence and characteristic of the flow instability was developed. The capability of the model in predicting the onset of flow instabilities was validated against benchmark tests and experimental data. Validation results show that the numerical model is able to provide reliable estimates of stability boundary and also can validly identify the flow excursion instabilities and the density wave oscillations. Numerical simulations were carried out to study the effect of different operating and geometric conditions on modeling single channel and parallel-channel flow instabilities. The results aim at the assessment of the developed model for detecting and describing flow instabilities at supercritical pressure. In this respect, the analysis results can provide useful understanding and guidance for planning experimental campaigns or avoiding flow instability in SCWR.