The book tries to manifest on the numerical analysis of a flow in all stages of a multistage centrifugal pump including of an impeller, diffuser & return vanes, and casing. The continuity and Navier-Stokes equations with the Realizable k- ¿ Model and standard wall functions are used. Computational study is utilized to study the flow behavior inside the 7-stage centrifugal pump. Study is carried out by the commercial code ¿ANSYS-Fluent¿. Numerical performance curve is drawn. Flow is steadily simulated. Flow rate is converted at mass flow equal to different flow rates in kg/s for 2980 rpm with full-domain solution. Computational study for all stages as a whole is analyzed, using the parallel computational technology, in ¿HPC¿ which is costly but more accurate. In this paper a cluster size in with 32 cores and 132 Gb ram is used. The process to benefit ¿HPCs¿ have advantages over normal industrial PCs and can reduce the time of processing, in this paper it is reveal that the results that are taken from normal PCs which split large models to stages analysis have considerable differences in flow patterns in comparison with whole model analysis.