Abstract
The advanced technology with supercritical fluids has been adopted in many aspects, such as the current new type of thermal power plants and the next-generation nuclear power plants. The external vibrations, e.g. seismic motion, imposed on such systems would generate substantial effects on the supercritical flows as well as structure parts. It could cause the fluctuations in flow properties to affect the stability and safe operation of a supercritical heated system through multiple feedbacks. At present, the relevant study concerning the external vibration on the supercritical heated system is quite sparse in the literatures. Therefore, this study develops a nonlinear dynamic model of a uniformly heated channel with supercritical water under external vertical accelerations based on three-region model and external force method. The present model validated against the experimental data could reasonably apply to explore the density-wave stability issues of a supercritical heated system coupled with the influence of vertical acceleration. The resonance oscillations would be triggered if the external vibration frequency is near the system natural frequency. The strength of resonance effect may depend on the inherent stability characteristics of the initial states. Moreover, this study could simulate the impact of vertical seismic acceleration on the dynamic behaviors of the system.