The Vortex Pump Under Highly Viscous Liquid Flow Conditions

The hydraulic performance and flow patterns in a standard motor-connected vortex pump with a specific speed of 76 are tackled by using CFD method under water and highly viscous oil flow conditions. The variations in performance curve and hydraulic loss caused from increased liquid viscosity are clarified; the flow rate, head and efficiency correction factors are correlated with impeller Reynolds number under three operating conditions and compared with centrifugal pumps. The flow patterns in the casing chamber, meridional plane and blade-to-blade plane are demonstrated. The impeller disc friction loss power and dimensionless liquid angular velocity in the casing chamber, incidence loss and slip factor are discussed. The pump hydraulic loss and total efficiency were decomposed and presented. It is shown that liquid viscosity exhibits a less effect on both flow rate and efficiency correction factors, but a more substantial influence on head correction factor. If the Reynolds number is not smaller than 1 x 10(4), the vortex pump can maintain a better performance and is suitable to transport liquids more viscous than water. The impeller disc friction loss power in the vortex pump is only 5% of the shaft power in maximum, so the vortex pump is a pump with lower impeller disc friction loss in comparison with centrifugal pumps. The circulating flow efficiency is volumetric efficiency actually and is the factor controlling the total efficiency of the pump.