Optimal design and experiment of propellers for high altitude airship

The multi-objective optimization design method and experimental validation of the propeller for high altitude airships are presented in this paper. The method of predicting the propeller’s aerodynamic characteristics is based on the vortex theory. The non-dominated sorting genetic algorithm II is introduced and applied to solve the optimization problem. Then the optimization model which aims to design an efficient and lightweight propeller for high altitude airships is established based on the conditions of high altitude airships propulsion system. In addition, the effects of various design variables including pitch angle, chord length, diameter, rotational speed, and the number of blades on high altitude propeller performance are presented and discussed in a gradual manner. The optimization results indicate that the desirable tradeoff between the efficiency and weight of high altitude propeller is associated with the absorbed power, structural strength, and even the manufacturing and installation conditions. In order to evaluate the mathematical model and performance of the optimized propeller, wind tunnel experiments of scaled model on the basis of scaling laws and the full-scale propeller test using mobile testing system were carried out. It is shown that results obtained from the experiments agree well with those of the numerical calculation, which verifies that the designed propeller can satisfy the requirements of the high altitude airships’ propulsion system.