声学风洞风扇段流场结构数值模拟

Numerical study about flow field characteristics of aero-acoustics wind tunnel′s fan section

采用数值模拟方法对0.55m×0.4m低湍流度航空声学风洞风扇段的流场特性进行了研究,并将计算结果与试验数据进行了对比,可以看到,本文采用的方法能对风扇段性能进行较为准确的模拟;随后根据叶片的流动现象,分析了动叶和静叶的性能表现,了解了风扇段内部的工作性态。最后给出了不同动静叶间距、不同静叶后掠角、不同静叶倾斜角对风扇性能、流动性态的影响,并根据流场结构分析了降噪机理。数值结果表明,采用静叶后掠和倾斜,并适当增大动静叶间距,可以在不影响风扇性能的情况下有效抑制噪声。同时,静叶后掠和倾斜还能有效增加风扇段出口速度的均匀性,特别是切向速度。

This paper is the numerical investigation reports about field characteristic of fan section. First, it presents the control equations and boundary conditions for numerical simulation. Then the details of numerical results are given about velocity characteristics of fan section in 0.55m×0.4m low turbulence aeroacoustics wind tunnel. Conclusion could be got that numerical methods used could give rational results comparing with experiment data. Then, basing on the flow around rotor and stator, the flow mechanism inside fan section was analyzed. At last different fan models were study based on the numerical results. These parameters imposed influence on performance and flow mechanism of fan including the distance between rotor and stator, stator swept and leaned. Stator leaned could significantly reduce or eliminate rotor wake and tip separation, and could produce a more uniform velocity profile at exit. Conclusions state the importance and feasibility of CFD in aerodynamical design of fan section in wind tunnel.