  The article describes research of fluid flow inside an axial-flow pump that
includes guide vanes, impeller and discharge diffuser. Three impellers with
different hub ratio were researched. The article presents the performance
curves and velocity distributions behind each of the impeller obtained by
computational and experimental ways at six different capacities. The velocity
distributions behind the detached guide vanes of different hub ratio are also
presented. The computational results were obtained using the software tools
CFX-BladeGenPlus and CFX-TASCflow. The experimental performance curves were
obtained using the standard procedure. The experimental velocity distributions
were obtained by probing of the flow. Good correspondence of results, both for
performance curves and velocity distributions, was obtained for most of the
considered cases. As it was demonstrated, the performance curves of the pump
depend essentially on the impeller hub ratio. Velocity distributions behind the
impeller depend strongly on the impeller hub ratio and capacity. Conclusions
concerning these dependencies are drawn.
