畸变进气条件下压入式矿用对旋主通风机失速机理研究

Study on Stall Mechanism of Mining Contra-rotating Main Fan for Forced Type Ventilation under Distortion Air Intake Condition

为了揭示畸变进气条件下,压入式矿用对旋主通风机内部非定常流动特性及失速机理,将分离涡模拟(Detached eddy simulation,DES)方法和出口节流阀函数相结合,对对旋风机三维全流道内的流动进行数值模拟与分析。结果表明:在节流阀系数为0.8的开度下,两级叶轮区域均出现了失速扰动,且扰动的起始位置均发生在叶顶处;虽然后级叶轮叶根区域也同样出现扰动,但这种扰动与叶顶区域的扰动是各自独立形成的,“突尖型”失速先兆伴随着“前缘溢流”与“尾迹反流”现象的发生而出现。虽然后级叶轮相对于前级叶轮先发生失速先兆现象,但随着流量的减小,在完全失速阶段,前级叶轮叶顶间隙内的气流脉动强度明显高于后级叶轮,两级叶轮之间的干涉作用强烈。

In order to reveal the unsteady flow characteristics and stall mechanism of a mining contra-rotating main fan for forced type ventilation under the distortion air intake condition,numerical simulation and analysis of the flow in the three-dimensional full flow-field of the contra-rotating fan are carried out by combining the Detached Eddy Simulation(DES)method with the outlet throttle function.The results show that when the throttle coefficient is 0.8 degrees,the stall disturbance occurs in both impellers,and the starting disturbance occurs at the tip of the blade.Even disturbance exists in the region near the blade root of the rear impeller,however,the disturbance near the blade root and disturbances in the tip region are formed independently."Spike-type"stall inception is accompanied by the occurrence of"leading edge overflow"and"trailing edge backflow".Although the occurrence of stall precursor in the rear impeller is earlier than that in the front impeller,the fluctuation intensity of air flow in the tip clearance of the front impeller is significantly more violent than that in the rear impeller as the flow rate decreases,and the interference effect between the two impellers is serious.