3D Inverse Design of Centrifugal Compressor Impellers with Splitter Blades

In the design of centrifugal compressor impellers with splitter blades it is quite common to use the same blade shapes on the full and splitter blades with the splitters placed at the mid-pitch location. However, recent results using conventional design methodology have indicated that by moving the pitch wise location of the leading edge of the splitter it is possible to improve splitter performance.

3D inverse design is developed for the design of compressor impellers with splitters. In this design method the blades are designed subject to a specified distribution of the circulation on the full and splitter blades. The choice of loading (or derivative of circulation with respect to meridional distance) and stacking condition to limit the complexity of the blade shape. Two different generic impellers are designed with different splitter leading edge location. The performance of these inverse designed impellers is then compared with the corresponding conventional impellers by using a 3D viscous code at design and off design conditions.

The blade geometry on the full and splitter blades are designed by using a specified circulation distribution. By controlling the circulation (and therefore loading) distribution on the splitter blades as well as the full blades the method allows a designer to optimise the splitter geometry with ease. Inverse design allows ability to choose loading distribution independently can provide considerable flexibility in the choice of design parameters.