叶片顶切对大型轴流风机性能的影响

对等环量设计的动叶可调大型轴流风机的叶片进行顶切,通过整机三维流场分析,得到了不同轮毂比和不同动叶安装角度的风机性能曲线.通过采用两种流量系数表示方法,对切割后的风机性能进行了对比分析,发现当轮毂比从0.56变化为0.6和0.65时,即切割量小于叶片长度30％时,风机的无因次性能曲线基本没有变化；当轮毂比切割为0.7时,风机性能明显恶化,通过叶片切割来改变风机流量的方法不再适用.

Effects of Blade Cutting on the Performance of Large-type Axial-flow Fan

The cutting are carried out from the blades tip in a large axial flow fan with adjustable rotor blades and equivalent circulation design,the performance curve of different hub-tip ratio and rotor blade installation angle is obtained based on three dimensional flow field analysis.With the use of two different nondimensional flow coefficients,it is revealed that for the cases of hub-tip ratio changing from 0.56 to 0.6 and 0.65,which means a 30 % percent reduction in blade length,the dimensionless characteristic of the original fan on the basis of the first kind of flow coefficient can still be used in performance prediction of the blade-cut fans;whereas for the cases that the hub-tip ratio is 0.7,the performance of the fans with cut blades will deteriorate obviously and the method of using blades cutting to change fan flow is not suitable.