Study on Frequency and Time Domain Analysis of Flow-Induced Vibration Response of Core Barrel

Different calculation methods of flow-induced vibration of the reactor vessel internals (RVI) are studied in this paper, that is frequency domain analysis and time domain analysis. Firstly, considering the fluid-structure interaction between the core barrel (CB) and the reactor pressure vessel (RPV), the CB and the heavy reflector, the finite element model of the CB in water is established and the results of its vibration characteristics are obtained, which is consistent with the test results. Based on the flow-induced vibration test of the RVI scale model, the fluctuating pressure data of the CB is obtained. The parameters such as power spectral density (PSD), correlation length and coherence function are obtained by processing the test data. Thus, the cross-power spectral density between any two points is got through these parameters. The root mean square (RMS) response of the CB is obtained by random vibration analysis (frequency domain). Then, the CFD model is established and large eddy simulation (LES) is used to obtain the time history of the fluctuating pressure of the CB. The response of the CB is obtained by time integration method (time domain). The calculation results by using these two methods are in good agreement with the experimental results.