Development of Global Optimization Method by Orthogonal Array (Application to Turbine Stage Design)

A new optimization method for the design of axial turbine stages is described, which can search for the global optimum solution and decrease the number of iterations. In order to realize high efficiency in turbines, it is necessary not only to apply the latest technology to turbine apparatus, but also to optimize various design factors using conventional technology for the purpose of cost effectiveness. The feature of the new method include creating orthogonal arrays and changing the level value of design factors for every search step. The orthogonal array is selected based on the number of factors & levels, and the level values are changed based on the trend of the optimum solution. As a result of applying the method to the optimum design of turbine stages, it is shown that the method can search the global optimum solution at approximately one seventh of the iterations of Ga or SA.