Design of a 160% pitch passage for cascade experiments using optimization methods

A linear turbine cascade experimental apparatus often consists of only a few cascade blades. Advantages to this arrangement are increased from using larger cascade blades and easier optical access. However, fewer cascade blades in the cascade row make it difficult to establish periodic flow conditions between blades. In this study, a 160% pitch passage for cascade experiments with a single blade is designed to satisfy infinite cascade flow conditions without any flow control or tailboards. Fourteen geometric design variables are applied to the design of a 160% pitch passage by using a gradient-based optimization method and a genetic algorithm. Flow structures within a passage designed with a genetic algorithm are closer to the infinite cascade flow conditions than those obtained with a gradient-based method. The results show that infinite cascade flow conditions can be obtained by modifying only the passage walls of the cascade experimental apparatus.