Mechanism for Onset of Sudden-Rising Head Effect in Centrifugal Pump When Handling Viscous Oils

The “sudden-rising head effect” may be prevalent in the head curve when a centrifugal pump transports highly viscous liquids, but it is not well understood presently. To clarify this effect the hydraulic performance of centrifugal pump when handling water and viscous oils was evaluated numerically by using a CFD code. The “sudden-rising head effect” is confirmed to exist at a higher viscosity and a certain large surface roughness. The viscosity and roughness, which make a transition of boundary layer flow pattern in both the impeller and volute to the hydraulically smooth regime from the fully rough one, are responsible for the effect.