倾斜蜗舌对前弯离心风机蜗舌区域流动影响的数值研究

为分析蜗舌的不同倾斜角度对离心风机蜗舌区域的非定常流动特征的影响,本文以一款高压前向离心风机为研究对象,对3种不同倾角的蜗舌结构风机进行了稳态的三维流场计算,并采用大涡模拟方法对其最优工况进行了非定常数值模拟。结果表明:随着蜗舌倾角的增加风机全压大致呈线性下降趋势,而适当的蜗舌倾角有利于提高风机的效率;蜗舌表面最高压力区随着倾角的增大,逐渐从蜗舌顶部中间位置向靠近后盖板侧的蜗舌顶部移动;不同倾角下蜗舌中间点P_2的压力脉动主频均为叶片通过频率,而点P_1和P_3的压力脉动主频为叶轮转频或其2倍转频。

Numerical Analysis of Flow Characteristics in Volute Tongue of Forward Curved Centrifugal Fan Affected by Inclined Volute Tongue

In order to analyze the unsteady flow characteristics in the tongue area of centrifugal fan under the tongues with different inclined angle,this paper takes a forward centrifugal fan for study. Three different types of modified centrifugal fans were simulated and unsteady numerical simulation was conducted using large-eddy simulation at optimum condition. The results indicated that as the inclined angle increased,the total pressure of the centrifugal fan reduced,and an appropriate tilt angle could enhance the total pressure efficiency. Besides,as the inclined angle increased,the highest pressure region moved from the middle position of tongue to the position near the back cover plate. For different inclined angle configurations,the blade passing frequency was dominate in the pressure fluctuation of point P_2 on the middle position of tongue,while the rotating frequency or two times rotating frequency dominated the pressure pulsations of point P_1 and P_3.