涵道螺旋桨与孤立螺旋桨气动特性的 数值模拟对比

基于非结构动态嵌套网格方法,对涵道螺旋桨与孤立螺旋桨的气动特性进行了非定常Euler方程数值模拟对比研究和分析.将计算区域分成旋转区与静止区两个子域,生成相互重叠的嵌套网格,有效地解决了螺旋桨与涵道以及静止部分桨毂之间的相对旋转问题.计算结果与实验结果相一致,验证了计算方法的正确性.涵道入口前缘形成的负压区是产生涵道附加拉力的原因所在.对比计算结果表明:与孤立螺旋桨相比,涵道的存在改善了螺旋桨桨尖区域的绕流特性,减小了桨尖损失;相同转速情况下,涵道螺旋桨产生更大的拉力,而所需功率略小,涵道螺旋桨系统具有更高的气动效率. 

Numerical simulation and comparison of aerodynamic characteristics between ducted and isolated propellers

The complicated flows around the ducted and isolated propellers were numerically simulated by solving the unsteady Euler equations based on unstructured dynamic overset grids,and the aerodynamic characteristics between them were compared.For the effective treatment of the complicated flow field involving relative motion between the propeller and duct,the computational domain was decomposed into two subzones,namely,rotational subzone and stationary subzone.The rotational subzone contained the propeller and the stationary subzone contained the duct.The good agreement between the present calculation result and experimental data demonstrates that the present method has good accuracy to simulate ducted-propeller problems.The lower-pressure area at the leading duct leads to the generation of additional thrust on the duct.Compared to the isolated propeller,the existence of duct changes the flow characteristic around the blade tip,and decreases the tip-loss.For the same rotational speed of the propeller,the ducted-propeller can generate greater thrust with less power,resulting in the conclusion that the ducted-propeller system has a better aerodynamic efficiency.