摘要：The paper is concerned with the fluid flow in the impeller side clearances of a centrifugal pump with volute *** flow conditions in these small axial gaps are of significant importance for a number of effects such as disk friction,leakage losses or hydraulic axial thrust to name but a *** the investigated single stage pump,the flow pattern in the volute turns out to be asymmetric even at design flow *** gain a detailed insight into the flow structure,numerical simulations of the complete pump including the impeller side clearances are ***,the hydraulic head and the radial pressure distributions in the impeller side clearances are measured and compared with the numerical *** configurations of the impeller,either with or without balancing holes,are ***,three different operating points,i.e.:design point,part load or overload conditions are *** addition,analytical calculations are accomplished to determine the pressure distri-butions in the impeller side *** accurate boundary conditions are available,the 1D flow models used in this paper can provide reasonable results for the radial static pressure distribution in the impeller side ***,a counter rotating wake region develops in the rear impeller side clearances in absence of balancing holes which severely affects the inflow and outflow conditions of the cavity in circumferential direction.