Drone Rotor Performance Under Icing Conditions

Abstract Low- and high-fidelity physics-based models for assessing the aerodynamic performance of drone and eVTOL rotors under icing conditions are examined. The low fidelity model in this work makes use of a lifting line model of the rotor with a prescribed inflow coupled to an ice accretion solver for modeling ice growth, and an interactive boundary layer model for the generation of airfoil drag polars. The higher fidelity model employed in this study uses a 3-D unsteady Navier-Stokes analysis with a tightly coupled water droplet transport model for modeling the collection of liquid droplets over the rotor. The rotor shape is periodically updated to account for the ice formation. Low fidelity calculations for an 81% scaled-down version of the Bell APT70 drone rotor tested at Université du Québec à Montréal provide reasonable estimates of the loss in thrust and rise in power during the initial stages of ice growth. Higher fidelity models are found to be better suited for multirotor configurations with nonlinear wake interactions, while eliminating the needs for airfoil drag polars, tip loss models, and empirical compressibility corrections.