Gurney襟翼对动叶可调轴流风机性能的影响

Effects of Gurney Flap on the Performance of a Variable Pitch Axial Flow Fan

以OB-84型动叶可调轴流风机为对象,采用数值模拟方法研究动叶尾缘处安装Gurney襟翼(GF)后对风机性能及内流特征的影响,并对其气动噪声进行评估。结果表明:增设GF可提高风机全压,且其高度越大,风机全压增幅越明显,同时促使最高风机效率点向大流量系数侧移动;高度为0.5%弦长的GF在动叶偏转±3°工况下均可提高大流量系数侧的风机效率;增设GF后,在叶顶处产生的次泄漏涡加剧了叶顶泄漏;尾缘下游区域产生的脱落涡增大了叶片吸力面与压力面间的压差;增设GF后风机气动噪声增大,选用高度为0.5%弦长的GF后,在设计工况点下风机全压和风机效率分别提高12.01%和3.13%。

The performance and internal dynamics of an OB-84type variable-pitch axial flow fan with Gurney flap(GF)installed at the trailing edge of rotating blades were numerically simulated,while the acoustic noise was predicted.Results show that GF could increase the total pressure rise of the fan,and the larger the height is,the greater the lifting range would be,and the working point of highest efficiency moves to the side with large flow rate.The GF with a height of 0.5%chord length could increase the fan efficiency on the side with large flow rate at blade pitch angles of 29°and 35°.After addition of GF,the secondary leakage vortex occurring on blade tip would aggravate the tip leakage;apair of shedding vortices appearing in the downstream of trailing edge would increase the pressure difference between the suction surface and the pressure surface.The addition of GF would lead to the increase in aerodynamic noise of the fan.When the GF with a height of 0.5%chord length is adopted,the total pressure rise and the fan efficiency would be increased by 12.01%and 3.13%,respectively.