Aerodynamic performance of a small-scale tilt rotor: Numerical simulation and experiment in steady state

Abstract

The present work studies the aerodynamic performance of a small-scale rotor in tilting transition states through wind tunnel tests and numerical simulations. Firstly, the test platform for the rotor aerodynamics is built up, and the Computational Fluid Dynamics (CFD) model of flow field around the rotors is established based on the multiple reference frame method. Secondly, the effects of flow velocity, tilt angle and advance ratio on the aerodynamic performance of the rotor are investigated using both the numerical simulation and the wind tunnel test. It is found that for the Model 8038 rotor with maximum effeciency of 0.567 at advance ratio of 0.43, the rotor thrust coefficient increases with the increase of the Reynolds number. At Reynolds number of 410 thousand to 820 thousand, the thrust coefficient increases slightly with the increase of the rotating speed. The results also show that the thrust coefficient decreases with the increase of the advance ratio. With high-speed airflow and relatively low-speed rotation, “windmill” phenomenon is found in the experiment. The tilting of the rotor from level flight to hovering increases the thrust coefficient. Highly dependency of the tilt angle on the thrust coefficients at given advance ratios is found in the wind tunnel tests.

Aerodynamics and Aeroacoustics Characterisation of Isolated Rotor in Hover and Transition to Forward Flight

“…As the tilting angle increases relative to the inflow direction, the rotor blade's thrust and power are expected to decrease at a given rotation rate [8]. Due to the unique flight segment, the noise characteristics of a tilt-rotor system varies depending on the loading condition experienced by the rotor.…”