离心风机叶片脊状结构减阻特性的三维数值分析  

Three-dimensional Numerical Analysis on Drag Reduction Characteristics of the Riblet Structure for Centrifugal Fan Blades

作　　者：吴正人[1] 郝晓飞[1] 戎瑞[1] 王松岭[1] 

机构地区：[1]电站设备状态监测与控制教育部重点实验室(华北电力大学),河北省保定市071003

出　　处：《中国电机工程学报》2014年第11期1815-1821,共7页Proceedings of the CSEE

基　　金：河北省自然科学基金项目(E2012502016);中央高校基本科研业务费专项资金资助项目(12QN39)~~

摘　　要：基于Realizable k-?紊流模型,采用Fluent软件对G4-73型离心风机单流道模型叶片翼型表面脊状结构的减阻特性进行了数值模拟研究,并分析了脊状结构对风机运行特性的影响。结果表明:适当尺寸的脊状结构布置能够使脊状表面单流道模型全压高于相同工况下的光滑表面模型,最大增幅7.98%,间接反映了叶片表面流动摩擦阻力的减少。脊状结构只对翼型表面的近壁面边界层分布有一定的影响,其沟谷内形成的稳定的二次流,可以有效减小沟谷内的表面剪切应力,证明了脊状结构具有的减阻效果。脊状表面湍流边界层近壁面的法向速度梯度和湍动能均明显低于光滑表面,验证了脊状结构对湍流耗散的抑制作用和具有的减阻效果。而脊状结构等距间隔的存在会增大部分区域的剪切应力,对减阻效果产生一定的不利影响。在偏离设计工况时,叶片压力面和吸力面分别产生的边界层分离现象也会影响脊状结构的减阻效果及其位置。文中所得研究结果可为工程实际中风机叶片的优化改型及性能改善提供参考依据。The drag reduction characteristics of riblet structure on aerofoil blade in the single channel model of G4-73 centrifugal fan were numerically simulated based on Realizable k-ε turbulence model with Fluent. Then the effects of riblet structure on the performance of centrifugal fan were researched. The results are as follows. The total pressure of the model with riblet structure in appropriate size is higher than that with smooth surface blade at the same condition, and the improvement can reach 7.98% at most, which indirectly reflects the reduction effect of flow loss. The riblet structure only has a certain impact on the distributions of boundary layer near the wall. And the wall shear stress on the valleys＇ surface could be reduced effectively by the stable secondary vortex formed within the valleys of the riblet structure, verifying the drag reduction effect of riblet structure. The gradients of the normal velocity near the wall in the turbulent boundary layer and the turbulent kinetic energy of the riblet surface are both lower than those of the smooth surface, which verifies the inhibition to the turbulent dissipation and drag reduction effect of the riblet structure. But the shear stress of some areas would increase because of the existence of the equal interval between the valleys, and this has a certain adverse effect on the drag reduction effect. In off-design conditions, the separation of the boundary layer on the pressure side or the suction side of the blade would also affect the drag reduction effect and its position of the riblet structure. The present results can be used to provide a valuable reference for the blade modification and performance improvement of centrifugal fan.

关 键 词：离心风机 单流道 脊状结构 减阻 数值模拟 

分 类 号：TH4[机械工程—机械制造及自动化] O355[理学—流体力学]