Ground wind tunnel test study of the propeller of stratospheric airships

In accordance with similarity criteria such as the equal Reynolds number and equal advance ratio, the paper established some similarity formulas about the thrust coefficient, the power coefficient and efficiency from the perspective of kinematic similarity and dynamical similarity for the propeller of stratosphere airships. The scaled model test of the propeller was carried out in Beijing University of Aeronautics and Astronautics ground wind tunnel. It shows that the experiment results basically tally with the results of the standard strip's theoretical calculation and numerical simulation. So it proves that the environment density has no effect on similarity parameters, and the scaled model test of the propeller can be carried out in the ground wind tunnel using the Reynolds number similarity criteria and the advanced ratio similarity criteria. There is no need of building special and costly low-density wind tunnel. Meanwhile, the experiment results also show that there is a large lateral contraction in the slip flow regime when the advance ratio of the propeller is less than 0.3. So lateral contraction correction is required for the nondimensional aerodynamic character curves calculated by the standard strip theory.