Experimental Analysis of Rotating Propeller Performance in a Wind Tunnel

Sammanfattning

Today, the ability to analyse drones is becoming increasingly vital for obvious reasons. This study investigates the performance of a small-scale propeller through wind tunnel testing. The findings intend to support the validation of numerical models used for solving flow fields, specifically Computational Fluid Dynamics (CFD) solvers. CFD solvers are widely used to predict aerodynamic behaviours, yet their accuracy is often unknown without experimental validation. Utilising the Royal Institute of Technology (KTH) L2000 wind tunnel, experiments were conducted on the APC 11x10E propeller. Test conditions covered: propeller speeds ranging from 5 000 to 10 000 rpm, free stream velocities from 0 to 30 m/s, and angles of attack from 0 to 70 degrees. The designed wind tunnel model includes components such as the propeller, a balance system for acquiring thrust and torque data, and a control system for operation and telemetry feedback. Key experimental findings showed thrust and torque variations across various flow conditions, revealing both expected and unexpected trends. Further, numerical solutions were obtained under identical conditions using a CFD solver called M-Edge (version 3.2) and a blade element momentum theory-based software called QBlade. While comparisons showed consistent trends in thrust and power coefficient curves, an offset in magnitude was observed and also, indications that temperature effects influenced the experimental findings negatively. While the primary goal of gathering empirical data was achieved, the main outcome of this study emphasises improvements for future experiments to enhance reliability of the experimental data. Consequently, these results should be used cautiously when validating numerical models.