Numerical assessment of ice formation processes and its impact on a variable-pitch unmanned aerial vehicles propeller in forward flight

Abstract

Unmanned aerial vehicles (UAVs) encounter significant challenges in freezing climates, as atmospheric ice accretion adversely impacts both flight safety and aerodynamic performance. This study provides an in-depth numerical investigation into the ice accretion process and its implications on the aerodynamic performance of UAV propeller. The analysis explores at various propeller blade pitching angles and rotational speeds. Detailed flow field analysis around propeller blade surfaces is conducted to address the performance degradations associated with ice accretion. The investigation reveals a noteworthy shift in ice shapes and extents with varying pitching angles and rotational speeds. The iced propeller demonstrates increased aerodynamic losses, marked by large size separation bubbles aft the ice shapes at outer radial locations. Remarkably, at higher pitching angles, the iced propeller outperforms the baseline propeller, followed by a propeller with increased rotating speed. For both baseline and higher pitching angles, the most significant losses in thrust coefficient 57.60% and 25.39%, respectively, occur at −2 °C, accompanied by maximum spikes in power coefficient of 140.08% and 93.92% at −4 °C. Meanwhile, an increase in rotating speed results in a decrease in thrust coefficient by 48.60% and an increase in power coefficient by 150.66% at an icing temperature of −4 °C.