Shape Optimization of Near-Space Airships Considering the Effect of the Propeller

Abstract

The stern-mounted propellers of near-space airships affect the aerodynamic characteristics of envelopes. Hence, the influence of propellers on the optimization design of envelopes should be considered. In this study, the computational fluid dynamics (CFD) simulation based on the γ-Reθ transition model was used as the main research method. An optimization model of an envelope with a propeller was also established. Envelopes with and without a propeller were optimized successively. Optimal results were analyzed using the CFD simulation. Results show that when the axial force coefficient of the propeller is 0.54, the drag coefficient of the optimal envelope considering the propeller is 16.5% lower than that without considering the propeller. The output power of the engine of the optimal airship considering the propeller can be reduced by 10.0% with the same advance speed. A wind tunnel test indicates that the drag coefficient and transition position of the envelope obtained by the CFD method are in good agreement with the test results. Therefore, the accuracy of the CFD method is sufficient, and the effect of optimization is evident.