A Novel Nonaxisymmetric Endwall Contouring for Turbine Cascade Using Automated Optimization

A novel nonaxisymmtric endwall contouring is presented to suppress the corner separation and to produce a more uniform exit flow angles. Firstly, a design methodology of automated optimization based on baseline is put forward. Hereafter, with respect to the contoured endwall and baseline, numerical simulations are conducted in an effort to gain further understanding of the effects of endwall contouring. The results demonstrate that with the addition of nonaxisymmetric endwall, the corner separation is enormously suppressed owing to the redistribution of the blade loading in the blade passage, furthermore, the total loss coefficient is decreased by 10% in the 128% Cax plane, and the underturning of the flow is reduced to a high degree, which clarifies the mechanisms of reduction in the secondary flow losses.

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