This paper presents a numerical investigation of the potential aerodynamic benefits of using endwall contouring in a fairly aggressive duct with six struts based on the platform for endwall design optimization. The platform is constructed by integrating adaptive genetic algorithm (AGA), design of experiments (DOE), response surface methodology (RSM) based on the artificial neural network (ANN), and a 3D Navier-Stokes solver. The visual analysis method based on DOE is used to define the design space and analyze the impact of the design parameters on the target function (response). Optimization of the axisymmetric and the non-axisymmetric endwall contouring in an S-shaped duct is performed and evaluated to minimize the total pressure loss. The optimal ducts are found to reduce the hub corner separation and suppress the migration of the low momentum fluid. The non-axisymmetric endwall contouring is shown to remove the separation completely and reduce the net duct loss by 32.7%.

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This paper presents both the computational and experimental results to assess the effectiveness of non-axisymmetric endwall contouring in linear cascades under different solidities. Endwalls were designed by geometric scaling of a prior optimized endwall. The results show that the total pressure loss can be reduced by the contoured endwall (CEW) under different solidities. The mechanism of the improvement of CEW is that the adverse pressure gradient (APG) has been reduced mainly through the groove configuration near the leading edge of the suction surface. Besides, the cross-passage pressure gradient (CPG) has also been reduced, which has the benefits to further suppress the corner separation. Moreover, there is an optimum range of the solidity for the CEW. For a lower solidity, the performance of the CEW at +7 degree incidence presents a rapid deterioration, due to the risk of flow separation near the mid-span, for a higher solidity, the profile loss can be more dominant.