Abstract: The study on small axial flow fan is carried out based on its flow field. Through numerical simulation of fan VD8025 using software Fluent and analysis of its internal and external flow fields, conclusions are drawn as follows：Separation vortex induced by boundary separation on blade suction side（non-working side） exists; blade tip vortex caused by secondary flow on blade pressure（working side） occurs; limited blade height inducing double vortex is being along axial. Above vortexes are illuminated by quantitative analysis on fan’s internal velocity distribution. Derived from quantitative analysis on fan’s outlet velocity distribution, the location away from fan’s outlet 120 mm is the best one for the fan ventilation.

Key words: small axial flow fan, internal flow field, external tube flow field, vortex

摘要： 小型轴流风扇的性能及降噪研究建立在流场研究的基础之上。通过对风扇VD8025的Fluent数值模拟，展开了其内外部流场的分析研究，结论如下：在叶片吸力面（非工作面）侧存在主要由边界层分离引起的分离涡，在叶片压力面（工作面）侧顶部间隙存在二次流引起的叶顶间隙涡，沿轴向存在有限叶高诱导双旋涡。对风扇内部流场的速度分布进行了定量分析，分析的结果说明了上述旋涡等流动情况的存在。由风扇出口管道速度分布的定量分析可得，对于所研究的风扇，距离风扇出口120 mm处为排风最佳位置。

关键词: 小型轴流风扇, 内部流场, 出口管道流场, 涡流