[关键词]
[摘要]
以某双级动叶可调轴流风机为对象,对其动叶片开展齿形襟翼尾缘结构改型。采用雷诺时均方程和k-ε湍流模型及大涡模拟对改型前后的风机性能进行了数值计算,分析了齿形襟翼不同齿长对风机性能、气动噪声及内流特征的影响及内在机理。结果表明:齿形襟翼可大幅提升风机性能,且全压增幅与齿长成反比;采用齿形襟翼后,风机效率峰值向大流量侧偏移,运行高效区增宽;〖JP2〗齿形襟翼可显著降低风机高频噪声,平均降噪量达13 dB;齿形襟翼改善了动叶尾涡结构,降低了叶中及叶根尾缘处能量耗散,影响了尾流逆压梯度区分布,减小了反向对涡核心区的二次回流强度,降低了风机气动噪声;齿长为0.8%弦长的齿形襟翼在改善效率、全压和降噪方面综合性能最优。
[Key word]
[Abstract]
A twostage variablepitch axial fan was taken as the research object, and the trailing edge structure of the toothed Gurney flap was adopted to optimize blades. The effect and mechanism of toothed flaps with different tooth lengths on fan performance, aerodynamic noise and internal dynamics were analyzed, and the original and modified fan performance was numerically calculated by using the Reynolds timeaveraged control equations, k-ε turbulent model and large eddy simulation (LES). The results show that the toothed flap can greatly improve the fan performance, and the total pressure rise is inversely proportional to the tooth lengths. After utilizing toothed flap, the peak efficiency of the fan shifts to the large flow rate side, and the high efficiency region is widened. The toothed flap can significantly reduce the high frequency noise of fan by an average reduction of 13 dB. The toothed flaps significantly improve the structure of wake vortex of blade, lower the energy dissipation at the trailing edge of middle and root of blades, affect the reverse pressure gradient distribution in the wake, diminish the strength of the secondary recirculation flow in the vortex core, and then alleviate the aerodynamic noise of the fan. The toothed flap with the tooth length of 0.8% chord presents the best comprehensive performance in improving efficiency, raising total pressure and reducing noise.
[中图分类号]
TK83
[基金项目]
国家自然科学基金(11602085)