A Quasi-One-Dimensional CFD Model for Multistage Compressors

In this contribution a quasi-one-dimensional tool for stationary and transient simulations of post-stall flows in multistage axial compressors is presented. An adapted version of the 1D Euler equations with additional source terms is discretized with a finite volume method and solved in time by a fourth-order Runge-Kutta scheme. The equations are discretized at mid-span both inside the blade rows and the non-bladed regions. The source terms express the blade-flow interactions and are estimated by calculating the velocity triangles for each blade row. Several loss and deviation correlations are implemented and compared to experimental data in normal flow, stalled flow and reversed flow regions. Transient simulations are carried out and a parameter study is presented to analyze the shape of the surge cycles and the frequency of the surge oscillations. At last, a bleeding control strategy is implemented to study the recoverability of the instabilities in a compression system.