Experimental Investigation of the Steady-State Flow Field with Particle Image Velocimetry on a Nozzle Check Valve and Its Dynamic Behaviour on the Pipeline System

Abstract

In the present work, to investigate the hydraulic losses and safe operation of nozzle check valves in industrial piping systems, the static characteristics of the valve and its dynamic behavior in the pipeline system were studied using an experimental bench with a visual DN300 nozzle check valve. Besides, basing on the PIV (Particle Image Velocimetry) technique measures the valve steady-state flow field under the different flow rates. The study has shown that as the flow rate rises, the valve disc displacement slowly increases to 44 mm, then rapidly increases to a maximum displacement of 72 mm. When the Reynolds number exceeds 5 × 105, the relationship between pressure drop and flow obeys a quadratic function. The local vortex area formed by the flow passage near the downstream deflector expands with the flow improvement. As the increase of flowrate, at low flow operating conditions, the downstream flow velocity in the local high-speed area near the valve body increases; at medium operating conditions, the area’s flow velocity decreases; at high flow work, this local high-speed area disappears. When the fluid deceleration is lower than 4 m/s2, the dynamic behavior satisfies the quadratic curve when the maximum slope is only 0.354, which shows that this nozzle check valve has a favorable response to the system.