Transient performance of a dual disc check valve during the opening period

Check valves are essential components to prevent reverse flow within the nuclear industry. Check valves enable the parallel pump systems operating at part load that only some of their branches are put into operation, consequently energy is saved. Many researchers have focused on check valve closure transient and the water hammer phenomena induced, yet few papers have been published on its opening transient characteristics. This paper elaborates on the transient study of a dual disc check valve during the opening period. An unsteady CFD method is applied to simulate the transient characteristics and the internal flow field of the check valve. The experiment of transient characteristics is conducted on a typical pump-valve test bench, which verifies the validity of the CFD results. An approximation of disc rotation characteristics is given, based on the comparison between the experimental results and the CFD approaches. The approximation method is verified on another check valve simulation with different boundary conditions and external moments. The visualization of the internal flow field evolutions is analyzed for a better understanding of the flow fields inside the check valve and its transient characteristics. This paper gives a detailed description of dual disc check valve opening during the pump starting period.