Numerical methods have become the basis for the aerodynamic design of turbomachinery in order to reduce the time for development cycles and associated cost. Designing modern axial compressors requires high confidence in the quality of numerical predictions. In terms of the aerodynamics, the loading of the blades as well as the efficiency targets constantly increase. Losses have to be predicted precisely and the impact of three-dimensional secondary flows, separation, and laminar-turbulent transition must be taken into account. In the present paper, the aerodynamic prediction quality of the state-of-the-art turbomachinery design code TRACE is validated against experimental data from a 2.5-stage axial compressor.

The aerodynamic prediction quality is systematically investigated to determine errors and uncertainties regarding the discretization, turbulence and transition models, and importance of considering unsteady effects. Computations are performed for several operating points and the results are validated by means of the compressors integral pressure ratio as well as by means of local pneumatic probe measurements. It is shown that using the empirical γ–ReΘ model improves the prediction quality of the boundary layers and wake flows. Time-resolved computations at the design point of the compressor show that the strength and the losses of a corner separation in both vane rows are reduced to realistic levels when the periodic-unsteady interaction with the upstream wakes is considered. The generally good aerodynamic predictions for both local and integral experimental quantities qualify TRACE for aeroelastic predictions which are planned for the future.

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