Riblet Surfaces for Performance Increase in Aircraft Turbines

The target of increasing environmental sustainability and reliability of the aero engines can be effectively achieved if correct decisions are made just in the preliminary design phase, when materials are identified with the scope to reduce fuel consumption and mechanical wear. The objective of this work is to describe a numerical procedure properly conceived to support the design of riblets. Riblets consist of micro-structures applied over the surfaces of turbomachines’ components in view of increasing the overall efficiency of the engine. Riblets can be generally thought as tiny streamwise grooved surfaces capable to reduce drag in the turbulent boundary layer. The aforementioned numerical methodology, based on the use of computational fluid dynamics (CFD) techniques and tools, makes it possible to determine the optimal size, position and effect of riblets on engine performance. Its use, then, constitutes an effective instrument enabling the quantification of the enhancement in terms of efficiency, CO2 emissions and noise generated, while guaranteeing an economical advantage. Adding customized numerical simulations in the preliminary phase of the turbine design of aero engines thus gives the chance to reduce the turbine’s length keeping the same performance, and to save material weight which has a positive impact on the overall efficiency of aircraft. The results described in this article were obtained in the Framework of ReSISTant, a research project co-financed by the European Commission under the Grant Agreement n. 760941.