A Novel Approach to Modeling of Compressor Characteristics

This paper presents a novel approach to modeling a turbojet engine compressor through the approximation and interpolation of performance characteristics. A hybrid method is proposed, fitting each speed line individually with the most suitable function from a predefined library of candidate functions. To address the ill-conditioning issue, a modified beta interpolation method is introduced. The beta curves arc carefully defined to ensure that the beta grid remains entirely within the map, avoiding extrapolation. Each beta curve is defined by a set of control points given by its intersections with speed lines, and an optimization problem is formulated to evenly distribute these points along the speed line. The resulting control points are parametrized for each beta curve, allowing for a coordinate transform that facilitates well-behaved nonlinear interpolation.