对转桨扇三维流场特性数值研究

对转桨扇（Contra-rotating propfan，CRP）是下一代民用航空推进备选方案开式转子发动机最重要的气动部件，其气动性能对整机性能影响显著。本文对不同进距比下的对转桨扇三维流场进行数值模拟，结合压气机及螺旋桨相关理论分析了对转桨扇内部流场及其滑流区涡结构和滑流特征。结果表明，对转桨扇后排流动特征及性能参数变化幅度均超过前排。对转桨扇实际进口气流角受到轮毂附面层、诱导速度、抽吸效应的共同影响，可根据不同叶高位置轴向速度的分布规律判断三种影响分别起主导作用的位置。在对转桨扇滑流区中，桨尖涡是导致损失的主要原因，径向涡量衰减比周向和轴向涡量衰减更快。对转桨扇滑流在径向上影响至3.5倍叶高位置。气流出后排桨扇后会持续加速直至静压达到环境压力，加速区域长度约为5倍桨扇半径。

Numerical Investigation on Three-Dimensional Flow-Filed Characteristics of Contra-Rotating Propfan

Contra-rotating propfan (CRP) is the most critical aerodynamic component of open rotor engine, and its aerodynamic performance has a huge impact on performance of the whole engine. Numerical simulations of the three-dimensional flow field of CRP with different advance ratios were carried out. The internal flow field of CRP and its vortex system structure in the wake and slipstream characteristics were analyzed on the basis of the theories of compressor and propeller. Results show that the flow characteristics and performance of the rear rotor change more than that of the front rotor. The actual inflow angle of the CRP is affected by the hub boundary layer, the induced velocity and the suction effect. The dominant position of three effects can be determined according to the distribution of axial velocity at different spans. The tip vortex is the main cause of loss in the slipstream, meanwhile, the radial vorticity decays faster than the circumferential and axial vorticity. The slipstream of CRP affects 3.5 times of the blade height. The outflow of the rear propfan continues to accelerate until its static pressure achieves the ambient pressure, the length of acceleration area is about 5 times of CRP radius.