短舱对螺旋桨滑流影响的IDDES数值模拟

基于非结构重叠网格技术,对短舱与螺旋桨滑流间的相互作用进行了非定常数值模拟研究。为了更好地捕捉螺旋桨尾涡的细节信息,计算采用基于Spalart-Allmaras模型的改进延迟脱体涡模拟(IDDES)方法,并在非定常计算过程中运用网格自适应技术以提高流场特征的空间分辨率。研究结果表明:IDDES方法获得的拉力系数计算值与实验值吻合良好,短舱的存在会增大螺旋桨的拉力系数;短舱对螺旋桨桨毂涡的结构影响较大,但对桨尖涡的螺旋结构影响较小;对单独螺旋桨算例来说,桨尖涡与桨毂涡的失稳发展过程都具有周期性,且在有/无短舱情况下桨尖涡的失稳位置相同,失稳后桨尖涡之间配对融合过程一致,从而说明桨毂涡对桨尖涡的失稳没有影响。

Numerical simulation of nacelle's effects on propeller slipstream based on IDDES model

Unsteady numerical simulation about the mutual effect between the nacelle and the propeller's slipstream was carried out based on unstructured overset grids algorithm. In order to better capture the detail of the propeller vortex structure, improved delayed detached eddy simulation (IDDES) based on Spalart-Allmaras model was employed, and the adaptive grid technique was used to improve the spatial resolution of the flow field's characteristics during the unsteady process. Research results show that the thrust coefficient calculated by IDDES agrees well with the experimental data, and the existence of the nacelle increases the thrust coefficient of the propeller. The nacelle has a great influence on the structure of the hub vortex but little effect on the structure of the propeller tip vortex. For the propeller without nacelle, both the instability process of the tip vortex and the hub vortex show obvious periodic characteristic. The inception region and the paring effects of the tip vortex of the propeller without nacelle are the same as those of the propeller with nacelle, which indicates that the hub vortex has no effect on the instability of the tip vortex.