Research on the construction of power spectral density function on the core barrel surface of pressurized water reactor

The construction of random turbulent excitation on the surface of reactor core barrel plays a very important role in the vibration fatigue analysis of the core barrel structure. In order to construct the power spectral density function of the core barrel surface, a semi-empirical formula is proposed based on the experimental load data and the turbulent kinetic energy simulated by Reynolds-Averaged Navier-Stokes (RANS). Firstly, through the hydraulic simulation test of the reactor internals, the fluid load and power spectral density function of the key points on the core barrel surface were obtained. Then, the fluid simulation of the reactor internals was carried out by Computational Fluid Dynamics (CFD) RANS solutions to obtain the turbulent kinetic energy on the surface of core barrel. Finally, the undetermined coefficient in the empirical formula was determined by the least square method. The results show that the semi-empirical formula proposed in this paper has a high degree of fitting reduction to the power spectral density of the measuring point. This method can obtain the load of the non-measuring point on the surface of the core barrel, which brings great convenience to the engineering design and evaluation of the flow-induced vibration of the reactor core barrel.