Aerodynamic Performance Characterization of UAV Propellers via Blade Element Momentum Theory including Post-Stall Behaviour

This work deals with the development of a numerical code for the evaluation of aerodynamic performance of UAV propellers combining the Blade Element Momentum Theory (BEMT) with empirical corrections for the extension to the post-stall behaviour of blade sections. The formulation also takes into account low-Reynolds effects and starts from the aerodynamic data of blade airfoils in 2D flow. The results of the developed model are verified against manufacturer database for two types of fixed-pitch propellers, over a wide range of advance ratio, aiming to cover the flow conditions related to hovering and cruise phases of a reference VTOL UAV. The results stability is demonstrated by a discretization convergence analysis, assessing the influence of sectional resolution on blades. Owing to the fast convergence of the solver, the proposed approach is expected to be effectively employed as a starting point of propeller design optimization loops.