Aerodynamic Design of Fan and Compressor Assembly for Turbofan Engines of Arbitrary By-pass Ratio, Based on Streamline Curvature Method

This paper deals with aerodynamic design of fan and compressor assembly for turbofan engines having arbitrary bypass ratios. Two different softwares were developed in this respect. First، based on general performance data at design point condition، a one-dimensional approach was activated. Initial flow passages of both fan and compressor، together with splitter position were developed utilizing row by row analysis along the meanline radius. Considering design restriction parameters، with diffusion factor as the most important one، the initial geometries of blades projection on the meridional plane and their numbers at each row was estimated. Then، these data were imported to the second software، developed for three-dimensional design purposes. This latter approach is based on the well-known streamline curvature method. Executing this computerized program، one can obtain the full geometries of fan and compressor blades with all gas dynamics data at different axial and radial positions. Different kinds of losses، including profile، shock wave and tip clearance losses were considered through the calculations، in order to evaluate entropy changes. To validate current design procedure، an existent two-stage fan was redesigned. Finally، a parametric study was carried out to investigate the effects of variations in some geometric and gas dynamics parameters on the general performances of either the fan or compressor modulus.