Quantification of the propeller slipstream effect on ice shed trajectories

Abstract

Ice accretion is a significant natural hazard which can occur during flight. It can lead to the degradation of the aircraft aerodynamic performance. For decades, engineers have tried to solve this ice accretion problem by integrating de-icing and anti-icing devices on the aircraft frame to maintain the performance. Nevertheless, the unknown trajectories of the detached particles remained an issue due to the complex physical flows around the aircraft. The detached ice particles from the wing or propeller strike the aircraft components, damaging them on impact. Their unknown trajectories reduce the safety of the aircraft structures, leading to major repairs and severe accidents. Numerical studies of these unknown trajectories are employed in order to reduce these dangers, especially behind the engine propeller where the ice particles are dismantled with high velocity. A good way of representing the probability of a trajectory to cross a plane perpendicular to the fuselage is called a footprint map. The objective of this thesis is to build a tool capable of studying the ice trajectory footprint map behind the propeller and the wing geometries. To correctly predict a footprint map at the propeller section of a turboprop, a 3D panel method (3DPM) is used as the numerical approach to compute the flowfield and these unknown trajectories around the propeller and wing. Additionally, a numerical tool called (Qprop) advanced Blade Element Method (BEMT) is used. (Qprop) is employed to determine the induced velocities needed to represent the slipstream produced by the propeller. The combination of both 3DPM and BEMT is used as a numerical tool for performing the interaction between propeller and wing study. A parametric study is made based on test cases on a single ice trajectory to show the parameters’ effect on the ice trajectory. Also, a probabilistic study of the ice particles footprints is done based on the 1000 trajectories to observe the most hit area by the ice chunks. Moreover, the Probability Distribution Function (PDF) in the area of the slipstream of the propeller is compared with the known literature PDF wing area without propeller slipstream. This comparison will allow for a better understanding of the ongoing threat to aviation safety of the propeller slipstream. This can be useful on different propeller and wing configurations to study the ice shed trajectories on various aircraft. Three main findings were yielded from this study. First, the ice trajectories were significantly affected by the propeller slipstream, as seen through the parametric study (single ice trajectory). This was supported further by the quantification of the propeller slipstream on the aircraft on 1000 ice trajectories. A lower lift and a higher rate of accretion above the wing behind the propeller were observed. Therefore, wing-only models are missing a key element : for turbo-prop aircraft, the propeller slipstream must be taken into account. The second finding is the validation of the drop in pressure coefficient on the wing behind the propeller. Finally, the third finding is the potential ice impact on the fuselage when decreasing the slipstream induced velocity.

Date	5 Apr 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	François Morency (Supervisor)