Study on flow field characteristics and fluid-induced resonance analysis of swing check valve

The purpose of this study is to investigate the vibration of the valve flap and rocker arm of DN25 swing check valve in piping system caused by fluid under working condition. Computational fluid dynamics (CFD), fluid–solid coupled modal analysis and harmonic response analysis are used to carry out non-constant flow field calculations and structural modal calculations. The flow field characteristics, pressure pulsations, modal frequencies and modal vibration modes of the flap and rocker stem of the rotary check valve at different opening degrees are obtained. The results show that the fluid in front of the valve is relatively stable, while the fluid behind the valve exhibits chaos and vortex. As the valve opening increases, the vortices dissipate and the fluid becomes orderly. The pressure pulsations are mainly concentrated in the high-velocity region downstream of the valve and gradually decrease as the valve opening in the flow direction increases. The peak frequency distribution of pressure pulsations caused by eddy currents and turbulence is in the range of 30 to 1000 Hz in the valve opening range of 0% to 20%. The peak frequencies of pressure pulsations at 5% and 10% opening are 539.56 Hz and 554.24 Hz, respectively, and the intrinsic mode frequencies are 539.44 Hz and 554.1 Hz. These frequencies are similar to those of the medium frequency resonance (FIR). The maximum amplitude of the pressure pulsation in the valve is 0.1763 mm in the Y-axis and 0.10669 mm in the Z-axis.