The objective of this project was to perform a design optimization on the main rotor blade of the UAV helicopter SARAH 4.0 from FLYING-CAM. The target was to achieve a higher aerodynamic efficiency, measured through the rotor's Figure of Merit (FoM) parameter.
The fast optimization performed with NUMECA Fine/Design3D optimization environment provided a 10.4% increase in the rotor thrust and a 16.2% increase in the rotor efficiency with comparison to the initial design. The rotor torque was contrained to its orginal value to prevent any engine redesign need.
The design optimization is performed in 3 main steps. Firstly, by the creation of a parametric model of the original geometry. Secondly, by the creation of a database containing various feasible and non-feasible designs generated by varying the free parameters of the parametric model of the blade. Finally, the fast convergence of the optimization algorithms permit to quickly identify the feasible (i.e. satisfying contraints)optimum of the problem.
For the present case, many physical parameters were optimized: angle of attack and twisting law, chord and thickness distributions as well as 3D blade tip design. The fine post-processing of the results allowed to identify that most of the performance gain is generated by the angle of attack and twisting law optimization.