Etude numérique de propulseurs cycloïdaux : analyse des écoulements internes et optimisation
Résumé:
As a new type of propulsion system, the cycloidal propeller has been attracting more attention recently. For a better design of such device, it is of great importance to understand the flow physics of the cycloidal propeller and how it affects the performance under different working conditions. In this thesis, the unsteady vortical flows over a two-bladed cycloidal rotor are simulated using the SST − ̃ transition model. The main contributions of the present work can be summarized as follows: (1) Analysis of the performances of the transition model over a single airfoil, in terms of the mesh distribution, inlet turbulence condition, correlations and parameters in the transition model, and then comparing the results with the experiments at different incidences and Reynolds numbers; (2) applying the optimized transition model to a cycloidal rotor at two advance coefficients, to investigate the internal flow structures in detail, mainly including the blade-wake interaction, wake-wake interaction, near-wall vortex flows and laminar-turbulence transition; (3) optimizing the cycloidal propeller, including the pitching kinematic, chord-to-radius ratio, pitch-pivot-point and blade profile.