Experimental and numerical investigation on dynamic characteristic of nozzle check valve and fluid-valve transient interaction

Abstract

Check valves play an important role in multiple systems within nuclear power plants. This study focuses on the valve closing process and investigates the dynamic characteristics, valve disc motion, and flow field of a nozzle check valve under different spring stiffness and fluid deceleration rates using experimental and numerical simulation methods. Experimental tests were conducted on a DN300 annular disc-type nozzle check valve with a spring stiffness of 3000 N/m, and the dynamic characteristic curve of the check valve was obtained. The curve exhibits a small maximum slope (0.0454), indicating good dynamic performance of the check valve. Numerical simulations were performed using the dynamic mesh method and RNG k-ε turbulence model to study the effects of different spring stiffness and fluid deceleration rates on the maximum reverse flow velocity, disc motion process, disc impact velocity, and internal flow field of the valve. The maximum reverse flow velocity was also corrected, and the resulting dynamic characteristic curve agrees well with experimental values. This study analyzes the influence of spring stiffness and fluid deceleration rate on various parameters during the dynamic closing process of the check valve. This study contributes to the optimization design of check valves and provides guidance for more accurate calculation of the dynamic characteristic curve of check valves through numerical simulations.