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 response to the increasing number of free trade agreements (FTA) and the Trans-Pacific Partnership (TTP), it is necessary to develop next-generation fishing vessels for the littoral sea of the Republic of Korea. The main objectives of such fishing vessels are to enhance the comfort of the crew and to improve fuel efficiency under the newly established principal dimension. This paper employs the hull form variation method to obtain a series of forebody hull forms of the 19 gross tonnage class of a coastal composite fishing vessel. Chine breadth modification has been used for hull form variations. The objective function is the minimum value of wavemaking resistance. A parametric study was conducted to observe the effects of design parameters on the objective functions, and hull-form optimization was performed. In addition to the hull-form optimization, the effect of the stern flap was investigated in terms of both resistance and operational performances.

In this study performance of two vertical pumps has been improved by using CFD. The first pump is a vaporization sea-water pump which has 6 blade impeller and the specific speed of about 410. The second one is the cargo pump of a chemical product carrier. This pump is a submersible pump operating near the bottom of the cargo hold and has the specific speed of about 210. In order to get higher efficiency, the flow fields of the initial models of the pumps are simulated, and design directions are obtained by analyzing the flow fields. NPSH required values are also calculated to know whether the design models have good cavitation performance or not. Satisfactory results are obtained for the design models.