Implementation of flow loss minimization incorporating the riblet technique on cascade profile and experimental validation

For the purpose of reducing the flow loss in the compressor cascade, the aerodynamic design of the blade geometry is essential. The traditional aerodynamic design focuses on curve modification, and the surface structure design is rarely considered in the optimization framework. Recent studies have revealed that micro riblet surface provides an excellent application prospect in drag reduction, which offers a new idea for the design of compressor cascade. In this paper, a concept of “geometry-flow loss” control is proposed, and an innovative optimization method combining profile and riblet design is developed further to improve the aerodynamic performances of the compressor cascade. In the design process of multiple iterations, the multi-scale simulations describing the whole flow field with a massive amount of grids would cause unaffordable costs. Therefore, the blade-riblets simplified simulation strategy is employed to evaluate the aerodynamic performances of the cascade profile with riblets and make the profile with riblet design practicable. The flow loss characteristics of the original cascade and two optimal cascades are assessed and verified by wind tunnel tests. The simulation and experimental results both indicate that the profile with the riblet design significantly further reduces the total pressure loss of the compressor cascade compared to the traditional profile design. The proposed concept in this paper increases the dimensionality of the geometry design and further exploits the design potential of the compressor cascade.