Influence of the rotor configuration on the electrostatic charging of helicopters

A helicopter flying through an atmosphere containing particulates may accumulate high electrostatic charges that can challenge its operational safety. In this paper the influence of the helicopter configuration on its electrification is reported. The current study is based on a recently developed numerical approach in which the turbulent airflow around the rotorcraft is estimated via large-eddy simulations, whereas the particulate flow is computed via Lagrangian particle tracking. Also, this approach incorporates a model for the triboelectric charge transfer during particle-helicopter collisions that is briefly described herein. The configurations examined in the study include rotor systems equipped with two, three, or four blades. Also investigated are the effects of the rotor size and its rotational frequency. The current results predict that a helicopter with fewer blades accumulates less electric current, even though the charge on each individual blade is higher. Furthermore, the location of the charge buildup on the rotor disk depends strongly on the number of blades. Also, according to current computations, a reduction of the rotor size leads to a reduction of its electrification, even if the blade tip velocity is kept constant