叶顶间隙对压入式矿用对旋主通风机叶顶区域流动性的影响

Influence of tip clearance on the flow near the blade tip clearance of forced mine contra-rotating main fan

为了研究叶顶间隙对压入式矿用对旋主通风机叶顶区域流动的影响,分别针对2mm、3mm和4mm三种叶顶间隙下风机全流道内的非定常流动进行数值模拟。结果表明:随着叶顶间隙的增大,在峰值效率工况下,叶顶区域的熵损失显著增大,后级叶顶区域的流动损失明显高于前级;在近失速工况下,前级叶顶区域出现了前缘溢流、尾缘反流现象,前级叶顶区域的流动损失比后级更大。在较大的叶顶间隙下,前级前缘叶顶泄漏流形成松散的涡系结构,诱导叶顶间隙的中部和尾缘区域的泄漏流形成回流和二次泄漏,堵塞叶顶区域的通道入口,引起“突尖型”失速起始扰动的发生。

In order to study the influence of tip clearance on the flow near the blade tip clearance of the forced mine contra-rotating main fan, numerical simulation of unsteady 3D flow in the whole flow passage of the fan is carried out for three tip clearances of 2mm, 3mm and 4mm, respectively. The results show that with the increase of tip clearance, under the peak efficiency conditions, the entropy loss in the tip region increases significantly, and the flow loss in the tip region of the rear stage is significantly higher than that of the front stage;under the near stall condition, the leading edge overflow and trailing edge reverse flow appear in the tip area of the front stage, and the flow loss in the front stage blade tip area is larger than that in the rear stage;under the large tip clearance, the leakage flow at the leading edge of the front stage impeller forms a loose vortex structure, which induces the leakage flow in the middle and trailing edge of the tip clearance to form backflow and secondary leakage flow, which blocks the channel entrance of the impeller tip area, thus results in the occurrence of the spike stall inception disturbance.