Abstract
The aerodynamic operating conditions of a propeller can include complex situations where vorticity from sources upstream can enter the propeller plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor plane and an eight-bladed propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.
Highlights
The blade vortex interaction (BVI) phenomenon is well known in the community of turbomachinery and rotorcraft aerodynamics
The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the propeller shaft
The current research could be applied to analyse the influence of the incoming vortex on the propeller, e.g., ground vortex, tip vortex shed from a control surface, etc
Summary
The blade vortex interaction (BVI) phenomenon is well known in the community of turbomachinery and rotorcraft aerodynamics. Besides the ground vortex impingement [4], the blade vortex interaction can . The presence of a concentrated vortex in the incoming flow leads to a non-uniform and distorted inflow into the engine [10], to an impulsive force on the blade [11] and to noise generation [12, 13]. The ground vortex influence on a turbofan engine inflow has been studied in terms of flow distortion. The vortex is generated from the tip of the lifting surface at positive incidence angle. The vortex with opposite circulation can be generated at negative incidence angle, the profile of the vortex axial flow velocity changes as the airfoil is not symmetrical. To adjust the vortex impinging position on the propeller, the wing can be moved in the transverse direction and spanwise direction
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