不同工况下对旋风机第二级叶轮转速匹配研究

Research on The Second Impellers Speeds Matching under Different Conditions of Counter-rotating Fan

介绍了对旋风机全三维数值模拟的基本过程与方法,利用数值模拟分析了两级叶轮等转速运行和第二级叶轮变转速匹配时的风机性能,结果表明:两级叶轮等转速运行时,对旋风机在小流量工况第二级叶轮压升增大,电机易过载,叶轮效率及整机效率下降;在大流量工况时第二级叶轮压升和效率明显降低,使整机性能大幅下降。采用第二级变转速匹配能够提高大流量工况的第二级叶轮的压升能力,降低小流量工况的第二级叶轮负荷,在保持设计点效率不变的同时提高了非额定工况的运行效率,扩大了对旋风机高效工作范围。

The basic process and method of full 3-D numerical simulation for counter-rotating fan was introduced. By using numerical simulation, the performance of counter-rotating fan had been discussed while two impellers speeds were equal, and the performance of counter-rotating fan had been researched under condition of the second impeller speed matching. The results showed that, when operating at equal speeds condition, the pressure-rise of the second impeller are increased which result in second motor overload and efficiency decreasing under small conditions. Under the large condition, the pressure and efficiency of the second impeller decreasing significantly which decreases the whole machine performance. By using the second impeller speed matching, the pressure-rise ability of the second impeller un der large flowrate condition has been increased and has been decreased under small flowrate condition. The operation efficiency under off-design conditions have been improved, meanwhile the operation efficiency under design condition maintained, and the high efficiency working range of counter-rotating fan has been expanded.