Closed valve flow field investigation using computational fluid dynamics

摘要

The flow field of a centrifugal pump operating at closed valve was investigated using Computational Fluid Dynamics (CFD). The rotor stator interactions were shown to directly link to the developed flow regime. The impeller flow regime was divided into two distinct areas. The upper proportion at the discharge vanes contained a vortex, the size and motion of which was influenced by the vane number ratio of stator to rotor vanes and the position of the rotor vanes with respect to the stator vanes The lower proportion of the impeller was filled with a strong flow reversal, which developed from the impeller hub and traversed to the shroud side spiralling out of the impeller eye into the suction duct. The suction duct flow regime contained a helically spiralling outflow near to the duct wall and a spiralling inflow core driven by the viscous forces imposed by the outflow regime. The pump casing showed a non-linear pressure development around the volute influenced by the stationary collector. The collector passages, which connect to the pump discharge, experienced pressure pulsations at the vane passing frequency.