叶根前缘VG对微型轴流风扇性能的影响

为降低微型轴流风扇叶根端壁区域二次流所引起的损失，根据涡流发生器的流动控制思想，提出一种在叶根前缘压力面侧设置微型直板的新型流动控制方法；以某微型轴流风扇为研究对象，采用数值模拟结合实验的方法，重点分析了不同安装角的涡流发生器对轴流风扇气动性能及内部流场的影响；研究结果表明：涡流发生器存在提高风扇静压与静压效率的最佳几何安装角，涡流发生器会对叶轮内部流场产生影响，由涡流发生器所形成的诱导涡与压力侧马蹄涡分支进行掺混，会削弱马蹄涡的强度，在一定程度上抑制了由马蹄涡参与演变成的通道涡的发展，使叶轮流道中流体进行再分配；在宏观方面，结构匹配的涡流发生器可提高风扇的气动性能，当涡流发生器安装角度为15°时，在风扇高效运行区间内同原型风扇相比，安装涡流发生器的风扇其静压最多提高8％，静压效率最大可提升2.4％。对于大轮毂比微型轴流风扇，由通道涡所引起的二次流损失不容忽视，同时在对叶轮进行设计优化时应重视叶根端壁处的结构设计。

The Effect of VG of Leading Edge of Blade Root on the Performance of Micro Axial Fan

In order to reduce the loss caused by the secondary flow in the end wall area of the blade root of the micro-axial flow fan, according to the flow control idea of the vortex generator, a new type of flow control method was proposed. In this method, a micro straight plate was set on the pressure surface side of the leading edge of the blade root. Taking a micro-axial fan as the research object, the effects of vortex generators with different installation angles on the aerodynamic performance of the axial fan and internal flow field were analyzed by numerical simulation combined with experiments. The research results showed that the vortex generator had the best geometric installation angle to improve the static pressure and static pressure efficiency of the fan. The vortex generator affected the internal flow field of the impeller. Mixing of the induced vortex formed by the vortex generator with the pressure-side horseshoe vortex branch would weaken the strength of the horseshoe vortex, inhibiting to a certain extent the development of the channel vortex evolved by the participation of the horseshoe vortex, allowing redistribution of the fluid in the impeller flow path. In the macroscopic aspect, the vortex generator with matching structure can improve the aerodynamic performance of the fan. When the installation angle of the vortex generator was 15°, compared with the prototype fan in the high-efficiency operation range of the fan, the static pressure of the fan with the vortex generator was increased by up to 8%, and the static pressure efficiency was increased by up to 2.4%. For micro-axial fans with a large wheel-to-hub ratio, the secondary flow loss caused by channel vortices cannot be ignored. At the same time, attention should be paid to the structural design at the end wall of blade root in the optimization of impeller design.