冷却风扇变密流型扭叶片设计方法及其气动特性的数值研究

A Design Approach of Variate Flow-rate for Twisted Blades of Cooling Fans and Numerical Investigation on Its Aerodynamic Performance

利用"径向平衡"原理,推导了轴流叶轮出口通流速度沿叶高的分布方程,并基于此提出了一种新的"变密流型"扭叶片设计方法.将该方法运用于某型叶轮的设计,并采用CFD技术,研究了该类扭叶片的气动特性.通过与传统的"等密流型"扭叶片及原始直叶片的气动性能的比较,发现"变密流型"扭叶片不仅能扩大小流量下风扇的稳定工况范围,而且其风压明显增加,有助于提高冷却风扇的散热性能.

The equation of the throughflow velocity＇s distribution at the outlet of the axial impeller along the blade＇s span was derived based on the principle of ＇Radial Equilibrium＇. On the basis of this equation, a new design approach of ＂Variate flow rate＂ was proposed for twisted blades. This approach was applied to the design for a certain kind of impeller. Combined with the application of CFD technique, the aerodynamic performance for this kind of twisted blades was investigated. Compared with the twisted blade designed by the traditional ＂Equal flow-rate＂ approach and original straight blade, the new twisted blade designed by the approach of ＂Variate flow rate＂ can not only enlarge the stable operating range of the fan under the condition of low flux, but also enhance the wind pressure obviously, which contributes to the improvement of the cooling fan＇s heat emission performance.