Abstract:The internal flow field, pressure distribution and hydrodynamic performance of a mixed-flow pump are studied in detail for a variety of speed, flow rate and surface roughness with FLUENT software. The relationship, which is among the efficiency, the head and the pressure difference between the blade pressure surface and the suction surface, was obtained by analyzing the pressure and velocity distributions of the blade pressure surface and the suction surface. The study shows that the hydrodynamic performance of the mixed-flow pump is proportional to increase of the speed; as the surface roughness is increasing, the torque and power increase, while the efficiency and head are significantly reduced.