Correlation of solidity and curved blade in compressor cascade design

Solidity is a primary parameter in prediction models of compressor design. Curved blade is a widely used 3d-blade-method for compressor performance improvement. This paper put curved blade angle into prediction models to develop its universal applicability in compressor design, then study the correlation of solidity and curved blade to find out the optimum matching principle of solidity and curved blade. Substantial compressor cascade cases for models are simulated with validated numerical method. The effect of solidity and curved blade on diffusion and loss under min-loss incidence condition are discussed. Then, a min-loss incidence (imin) model, a diffusion factor (Dimin) model and a total pressure loss (ωimin) model are established and validated by experiments. It indicates that the (ωimin)min cases of different Dimin are related to a matching principle of solidity and curved blade. Flow analysis shows that both curved blade and lower solidity decrease loss and meanwhile curved blade recovers the decreased diffusion caused by lower solidity. So, for a given Dimin, the optimum combination of curved blade and lower solidity becomes the ωiminmin case. This paper develops curved blade universal applicability, finds out optimum matching principle of solidity and curved blade, and brings benefits to advanced compressor design.