INVERSE 3D CAMBER-LINE CALCULATION TOOL INCA-3D

摘要

The modern aerodynamic design process of blades for commercial axial-flow compressors for aero-engines has to be fast but also accurate in terms of the blade and profile shaping. To achieve that, the three-dimensional flow effects, which have a significant impact on the optimum blade geometry, have to be considered in the early design phase. That requires fast software tools, which support the fully three-dimensional-design of compressor blades.This paper describes the software tool INCA-3D and its capabilities to calculate camber lines for compressor blade profiles inversely. INCA-3D is a Fortran coded software which runs on Unix and Windows operating systems and uses inviscid potential theory to calculate the camber lines of compressor rotor and stator blades based on the three-dimensional blade loading distribution.The input to the programme is the three-dimensional blade load distribution in terms of Δc_p, the distribution of space-to-chord ratio, stagger angle (inlet angle), Mach number, chord length and leading edge shape (sweep and dihedral), which can be taken from throughflow analysis and 2D-blade-to-blade calculations. The output of INCA-3D are camber lines distributions along chord for 21 blade heights equally distributed over the annulus in a format which can be read in by a blade generation software. An INCA-3D ran for a blade row takes, depending on the required accuracy, between 6 and 120 minutes and runs automatically. That means that a whole set of compressor blades can be generated within hours.The present paper shows the basic equations of the method, which INCA-3D is using and gives examples of the application of the software for different compressor test cases.