Prediction of Flow Features in Rotating Cavities With Axial Throughflow by RANS and LES

Abstract

Rotating cavities with axial throughflow are found inside the compressor rotors of turbomachines. The flow pattern and heat transfer in the cavities are known as sophisticated problems. In this paper, the 3D compressible flow field in a rotating cavity is investigated numerically using a steady RANS method, an unsteady RANS method and LES. The numerical results based on the three methods are analyzed in detail and compared with the available experimental data. For the LES method with a subgrid-scale model, the instantaneous flow structure and the heat transfer can be captured very well. For the unsteady RANS method with an appropriate turbulence model, the large-scale flow structure can be revealed acceptably, and the heat transfer solution agrees with the experimental data with a certain error. For the steady RANS method, a reasonable flow structure cannot be obtained, while the distribution of the heat transfer has a same tendency and uncertain error with the experiments. Therefore, it is suggested that the steady RANS method can still be a numerical tool in the quite preliminary design of the rotating cavities, while the LES is more advanced from an academic view. Moreover, the unsteady RANS method is most appropriate for industry. It should be valuable in the detailed design computations for selecting the optimized design.