平流层飞艇螺旋桨地面风洞试验

按照等雷诺数Re和等前进比λ相似准则,从平流层飞艇螺旋桨的运动和动力相似角度出发,建立了螺旋桨拉力系数、功率系数和效率等参数的相似公式,并在地面常规密度风洞中进行了螺旋桨的缩比模型试验.通过对有关试验结果与平流层原型桨的数值模拟和片条理论计算结果的对比分析可看出,三者基本吻合,从而说明地面风洞试验的环境密度大小基本不影响螺旋桨相似性参数,由此得到平流层飞艇螺旋桨可在地面常规密度风洞中按照等Re和等前进比相似准则进行缩比模型试验,而不必为此建立特制的昂贵的低密度环境风洞.同时,实验结果表明,在螺旋桨前进比小于0.3时的情况下,因滑流区侧向收缩大,片条理论计算的无量纲气动性能曲线需要进行侧收缩修正. 

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.