Multi-objective Shape Optimization of Airfoils for Mars Exploration Aircraft Propellers

This study aims to improve the aerodynamic performance of a propeller for Mars exploration aircraft by applying multi-objective shape optimization to its airfoils. To increase the accuracy of performance evaluation in the low-Reynolds-number and high-subsonic flows condition on Mars, a Reynolds-averaged Navier-Stokes simulation using the gamma-Re-theta transition model, which can predict the laminar separation bubble and the location of the laminar-turbulent transition with high accuracy, is employed. Furthermore, multi-objective shape optimization is performed using a shape-definition method with a high degree of freedom to enable the inclusion of a variety of airfoil shapes. A multi-objective genetic algorithm is used to determine the optimal airfoil shape, and a Kriging model is used to reduce the computation time. The Adkins method is used to determine the optimal shape of the propeller using the designed airfoil. Then, the performance and efficiency of the propeller are investigated. Results demonstrate improvements in the power consumption and efficiency of the propeller using the designed airfoil over those of the propellers using reference airfoils. Quantitative and qualitative correlations between the design variables and airfoil performance are also analyzed using analysis of variance and self-organizing map methods to extract the geometric features that affect airfoil performance.