Increase of Compressor Performance through the Use of Microstructures

Turbomachinery efficiency is becoming more and more relevant in order to reduce fuel consumption and mechanical wear of machines at the purpose of increasing their environmental sustainability and reliability. Optimized material identification and design is therefore of paramount importance. This paper describes how turbomachines can be optimized thanks to the effect of microstructures suitably created over the shapes of their constituting components in order to increase the overall efficiency via a simple coating solution. These structures, called riblets, consist of tiny streamwise grooved surfaces which are such to reduce drag in the turbulent boundary layer. Theoretical, numerical and experimental experiences gave a first estimation of the impact of riblets in industrial compressors. In this case, the riblet structures reduce the aerodynamic shear stress losses. The areas of higher interest are the diffuser and the volute, where the higher losses happen. The optimal size, position and effect on performance were analysed via simulation. The use of such an effective numerical means may give a precise evaluation about benefits in terms of efficiency increase as well as of CO2 and noise emission reduction and, for these reasons, it also has a positive economical and societal impact in relation to mobility and energy sector, considering the use of turbomachinery in avionics and power application. The presented activities were performed in the Framework of the ReSISTant project, which was co-financed by the European Union under the Grant Agreement n. 760941.