Influence of the Helicopter Configuration on its Electrostatic Charging

A helicopter flying through an atmosphere containing particulates may accumulate high electrostatic charges which can challenge its operational safety. In this paper we report on the influence of the helicopter configuration on its electrification. Our study is based on a recently developed numerical approach according to which the turbulent air flow around the rotorcraft is estimated via large eddy simulations while 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 that we examined in our study include rotor systems of two different sizes equipped with two, three or four blades. Our results reveal that a helicopter with fewer blades accumulates less electric current even though the charge on each individual blade is higher. Further, the location of the charge build-up on the rotor disk depends strongly on the number of blades. Also, according to our computations, a reduction of the rotor size leads to a reduction of its electrification, if all other parameters are kept constant