Multiobjective Design Exploration of Propeller Airfoils at Low-Reynolds and High-Mach Number Conditions towards Mars Airplane

Abstract

Multiobjective design explorations of airfoils for Mars airplane propeller blade are conducted to obtain insights into high efficiency Mars airplane propeller blade design in low Reynolds number and high Mach number condition. In this study, two airfoil design optimization problems at different Mach number in low Reynolds number condition are studied to understand the Mach number effect. Maximization of the lift coefficient and minimization of the drag coefficient are employed as the objective functions where the design valuables are control points of B-spline curves representing airfoil shape. The result of multiobjective aerodynamic optimization suggests that non-dominated solutions in low and high Mach number conditions have a similar trend, although these solutions in low Mach number condition are widely scattered. Dominant modes of non-dominated solutions relates with the large aft camber and thick near middle region of airfoil geometry when the Mach number is larger. The larger aft camber is observed as the common feature of the non-dominated solutions, and three-representative airfoils for minimum Cd, maximum l/d, and maximum Cl designs among the non-dominated solutions have a similar shape. The geometry becomes thicker the near middle region of the airfoil due to the Mach number effect.