Flow analysis was carried out for a double-suction centrifugal pump. An impeller-only model and a full pump model were used to simulate the velocity and the pressure field of the pump. Pump head and efficiency were calculated with flow rate in order to obtain general performance of the pump. The calculation results were compared to the experimental data, and satisfactory results were obtained. Also, the velocity and the pressure field of this pump were analyzed for the rated point and off-design points. Changes of the velocity and the pressure field with flow rate were investigated at impeller eye and impeller exit.

In this study, an optimization design method is established for a rotor blade of a Curtis turbine. Bezier curve is generally used to define the profile of turbine blades. However, this curve is not proper to a supersonic impulse turbine. Section shape of a supersonic turbine blade is composed of straight lines and circular arcs. That is, it has several constraints to define the section shape. Thus, in this study, a blade design method is developed by using B-spline curve in which local control is possible. The turbine blade section has been changed by varying three design parameters of exit blade angle, stagger angle and maximum camber. Then flow analyses have been carried out for the sections. Lift-drag ratio of the blade section is used as the object function, and it is maximized in the optimization. Second-order response surface model is employed to express the object function as a function of design parameters. Central composite design method is used to reduce the number of design points. Then, an evolution strategy is employed to obtain the optimized section of the Curtis turbine blade.

In this study, unsteady flow field of an industrial double-suction centrifugal pump has been solved to obtain the interaction between impeller and volute casing. Quasi-steady and unsteady methods have been used. A block-structured grid is employed to represent the complicated pump geometry. The velocity field and the pressure fields of the pump are analyzed for the rated point and off-design points. Magnitude of the interaction is evaluated numerically.

In order to obtain sufficient towing force, tug boats are usually equipped with high powered engines and special thrusters such as azimuth thrusters. The hydraulic design of a ducted azimuth thruster was carried out for a 2 MW-class tug boat by using CFD. Here, the azimuth thruster consists of a fixed-pitch screw propeller, a duct, a gear casing and a strut. To design the duct propeller, the effects of design parameters of a screw propeller and a nozzle on thruster performance were evaluated. The proper section shape of the strut is also important because it can largely affect inflow velocity distribution on the propeller. The model of the designed azimuth thruster was manufactured with a scale ratio of 10. Propeller open water and cavitation observation tests were carried out to confirm the performance of the design model.

In this study we introduce pump design work in which two vertical diffuser pumps are designed by using computational fluid dynamics and vane shape optimization. The first pump is a submergible pump having the specific speed of 300(m3/min-m-rpm). The effects of vane shape change on pump performance have been studied for this pump. Some effects of impeller inlet profile and diffuser blade angle are shown. Since this pump has very high head, the impeller exit angle of the first design model has been increased to get the specified head. This modification induces flow separation on the impeller blade. Blade angle distribution has been modified to eliminate the flow separation so that pump efficiency is maintained as high as in the base model. The second pump is a CWP for power plants having specific speed of 330. Blade shape is designed by using fractional factorial design method. The main effects and the interactions of design parameters are investigated. Impeller inlet diameter is increased to get better NPSH required performance. Flow analysis shows that the design model has higher efficiency and better cavitation performance than the existing model.