Propeller ice accretion effects on tandem propeller aerodynamics in eVTOL aircraft mode

Propeller-propeller interaction is one of the main sources of aerodynamic losses in electric Vertical Takeoff and Landing (eVTOL) aircraft. While previous studies have extensively investigated these interactions under clean conditions, the impact of ice accretion on wake-induced coupling between tandem propellers remains insufficiently understood. Under icy conditions, propeller performance degrades and wake structures become highly distorted, potentially amplifying their impact on downstream components. In this study, propeller interaction (defined as the aerodynamic coupling between upstream and downstream propellers through their wake and induced velocity fields) is investigated in airplane mode under different tandem configurations. Icing simulations are initially performed on a singular blade using FENSAP-ICE, whose methodology has been validated in our previous work, and the resulting ice geometries are later restructured to perform aerodynamic interaction analysis in ANSYS CFX. Findings show that propeller ice accretion, reduces thrust force, increases power demand and alters the boundary layer flow momentum. Thereby, enhancing the wake non-uniformity, intensifies turbulence and the changes local inflow conditions at rear propeller. Despite these changes, improved pressure recovery and reduced trailing edge separations are observed on the rear propeller. At severe icing conditions and maximum overlapping conditions, about 19% increase in thrust coefficients of downstream propeller observed than the clean wake case. The impacts of upstream propeller ice accretion decrease with the increase of the advance ratio and vertical offset distance between the propellers. The results of this work provide new insights into icing-induced propeller-propeller interaction mechanisms relevant to eVTOL aircraft operating in adverse atmospheric conditions.