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旋转失速现象的合理控制对扩大叶轮机械安全运行范围具有重要意义。基于离心风机失速发生机制的分析,提出了一种失速主动控制方法,即在靠近蜗舌的3个叶轮流道进口处进行喷嘴吹气。基于节流阀模型,对实施喷嘴吹气后离心风机内部的非定常流场进行了数值模拟。分析了4个阀门开度下,离心风机内部不同轴向截面的相对速度矢量图、静压等值线分布和声功率级云图。结果表明,原始风机发生旋转失速时流量为4.157 m3/s,喷嘴吹气后失速发生时流量为3.461 m3/s,安全裕度增大11%,扩稳效果明显。提出的喷嘴吹气失速控制方法对风机的安全运行具有重要的工程价值。
The reasonable control of rotating stall is of great significance to expand the safe operating range of impeller. Based on the analysis of the mechanism of centrifugal fan stall, a method of active stall control is proposed, in which the nozzle blows at the inlet of the three impeller runners close to the worm. Based on the throttle valve model, the unsteady flow field inside the centrifugal fan after the nozzle blowing is numerically simulated. The relative velocity vector, hydrostatic contour distribution and sound power level cloud chart of different axial sections of the centrifugal fan under four valve opening degrees were analyzed. The results show that the flow rate of the original fan is 4.157 m3 / s when the stall occurs, the flow rate of 3.461 m3 / s when the nozzle stalls after the air blowing, and the safety margin increases by 11%. The proposed nozzle blowing control method has important engineering value for the safe operation of the fan.