中文摘要：

采用全圆周数值模拟方法，研究了双级对旋式轴流风机的变转速匹配特性。在四种转速匹配方案下，对比分析了风机整机和各级转子的压升、效率和功率特性，进一步深入流场内部，揭示了不同转速匹配下的内部流动特征，并与单通道模拟结果做了对比。对单级转子特性而言，单通道模型和全圆模型间最大的区别在第二级转子，就全压升和效率来说，单通道模拟结果高于全圆周模拟结果。不同转速匹配下的结果均显示，第二级转子性能改变对转速变化更为敏感。除各级转子的良好设计，进口集流器和出口扩散器对提高对旋风机性能也很重要。

英文摘要：

The matching performance of a two stage contra-rotating axial flow fan under variable speed is investigated through full annulus numerical simulation. With four matching schemes of speed,the characteristics of total pressure rise ,efficiency and power of the whole machine and single stage are ana- lyzed and compared,furthermore the features of innerflowfield are elucidated,which results are compared with those of single passage simulation model.For the single stage rotor,the most differettce between single passage and full annulus simulation models is the characteristic of the second stage rotor.As for the total pressure rise and efficiency,the results of single passage model are obviously higher than those of the full annulus model.All the results under different speed matching scheme showe that the second stage rotor is more sensitive.Except for the well design of stage rotor,the inlet bell mouth and outlet diffuser are also im- portant for the performance improvement of contra-rotating axial flow fan.