【摘要】 为了改进风机调节门的性能和作用,采用五孔探针对平板直叶片调节门前后的流动进行了详细的测量,得到了流动参数沿流动方向的衰减变化规律.实验分析结果表明:调节门导致其下游流动沿半径方向的分布很不均匀,而沿圆周方向的分布比较均匀,对其上游流动的分布形态影响很小;阻力系数和预旋系数随调节门叶片角度的增大而增大,但在叶片角度大于40°~50°时阻力系数的增加明显快于预旋系数.针对风机调节门的流动特性,采用预旋系数、阻力系数做为全面评价风机调节门性能的主要指标是可行的.从兼顾流动均匀性和预旋两方面因素考虑,从调节门出口到叶轮进口之间的最佳距离约为叶片平均弦长的4~8倍.根据调节门流动参数沿径向、周向和沿轴向的分布特点,提出了加大调节门流道中心处叶片的弦长、改进平板直叶片叶型及优化最佳叶栅稠度等参数的建议.更多还原

【Abstract】 The upstream and downstream flowfields of a straight blade inlet guide vane(IGV) for a centrifugal fan were measured with a five-hole probe.The result shows that the radial distribution of the flowfield is unsymmetrical,while the circumferential distribution of flow is nearly symmetrical,and that IGV has nearly no influence on distribution of upstream flow.The resistance coefficient and the prerotation coefficient increase with the increment of the pitch angles of IGV.Moreover,the increment of resistance coefficient is much greater than that of prerotation coefficient when the pitch angles exceeds 40  50 degsees.Therefore the prerotation coefficient and the resistance coefficient coule be used as major parameters to evaluate the performance of IGV.The optimal gap between IGV and the impeller is about 4  8 times the length of the blade chord considering the symmetry and prerotation of the flow field.Based on the characteristics of the radial,circumferential and axial distribution of the flow field,some proposals are provided to enhance the performance of IGV,such as the increment of the blade chord at the center of IGV,improvement for the airfoil shape,and optimization of the cascade solidity.更多还原