微型轴流风扇扭叶片设计及其气动分析

通过推导微型轴流风扇叶片出口轴向速度沿叶高的分布方程,提出了一种考虑轴向速度非均匀性的扭叶片设计方法.通过计算流体动力学(CFD)技术,对利用该方法所设计的各种形式扭叶片的气动性能及其变工况时的气动特点进行了数值研究,并比较了工作于自模区与非自模区风扇的气动性能差异.研究结果表明,与自模区的风扇相比,非自模区的风扇压力曲线没有最高压力点,随流量减少压力几乎呈线性增加,且无失速点;效率曲线则显得更为平坦;按刚性涡设计的扭叶片虽效率低,但风压高;提高叶轮的轮毂比有助于提升风扇压力与效率.

Design of twisted blade for micro axial fans and its investigation of aerodynamic performance

A nonuniform distribution of axial velocity along the spanwise direction on the impeller outlet is presented,based on which an approach is proposed to design the twisted blade for micro axial fans considering the nonuniform axial velocity.By computational fluid dynamics(CFD) technique,the aerodynamic performances of different types of twisted blades are numerically investigated in the design and on the off-design operating conditions.The aerodynamic performances of the enlarged model fans in self-stimulated domain are compared with that of the micro-scale fans in non-self-stimulated domain.Results indicate: in non-selfstimulated domain,the pressure is almost linearly increased with the decreasing flowrate,there are no maximum pressure and no stalling point,and the efficiency curve tends to much smoother.Compred with the free vortex twisted blade,the twisted blade designed by rigid vortex generates higher pressure,but has lower efficiency.The improved ratio of hub to shroud may raise the pressure and efficiency for the micro axial fan.