动叶异向偏转对轴流风机失速的影响
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摘要
采用非定常数值模拟的方法捕捉失速现象,研究失速机理,所选择的对象为动叶可调式轴流风机,模型一的动叶安装角正常,模型二存在两个偏转角度为-9°和+9°的异常叶片。通过计算可以得知:两只异常叶片改变了同流量下风机的出口静压,但未改变风机运行的稳定范围。同正常叶片的失速变化过程相同,异常叶片的风机也会沿着失速预兆的发生、发展、合流,直到最终变成完整失速团这4个步骤。+9°异常叶片吸力面顶部是失速先兆的源头,而-9°异常叶片附近的流场相对平稳。异常风机产生失速先兆时刻的湍动能峰值较正常风机低72. 7%,形成完整失速团时刻的湍动能峰值较正常风机低41%,可见,异常叶片不但使失速先兆出现的时间前移,还减少了失速团的演化周期,该结论扩展了异常叶片影响失速变化过程的理论。
Taking a two-stage axial fan with adjustable vanes as the research object,the 3 D unsteady numerical simulation was conducted on the axial fan with abnormal installation angles of the second rotor based. The abnormal installation angles of two adjacent blade in the second rotor were-9°and +9°,and the other is normal fan. The numerical results show that although the abnormal blade changes the static pressure of the fan,the stable operating range of the fan is unchanged. The stall change process being the same as the normal fan,the fan with ± 9 abnormal angle experiences four stages before entering stall: appearance,development,merging and developing into stall cell. The top of suction surface in +9°blade is the source of stall precursor,and the flow field is stable around-9°blade. The peak value of turbulent kinetic energy in the abnormal fan is 72.7% lower than that of normal fan when the stall precursor appears and 41% lower when the complete stall cell has been formed. It can be seen that the abnormal blades not only advance the time of stall precursor,but also reduce the evolution of stall cell. The conclusion of the paper extends the theory about abnormal blade and stall.
Taking a two-stage axial fan with adjustable vanes as the research object,the 3 D unsteady numerical simulation was conducted on the axial fan with abnormal installation angles of the second rotor based. The abnormal installation angles of two adjacent blade in the second rotor were-9°and +9°,and the other is normal fan. The numerical results show that although the abnormal blade changes the static pressure of the fan,the stable operating range of the fan is unchanged. The stall change process being the same as the normal fan,the fan with ± 9 abnormal angle experiences four stages before entering stall: appearance,development,merging and developing into stall cell. The top of suction surface in +9°blade is the source of stall precursor,and the flow field is stable around-9°blade. The peak value of turbulent kinetic energy in the abnormal fan is 72.7% lower than that of normal fan when the stall precursor appears and 41% lower when the complete stall cell has been formed. It can be seen that the abnormal blades not only advance the time of stall precursor,but also reduce the evolution of stall cell. The conclusion of the paper extends the theory about abnormal blade and stall.
引文
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[8]孙鹏,傅文广,钟兢军.跨声速压气机突尖波型失速特征的数值研究[J].工程热物理学报,2018(1):76-81.
[9]周游天,李军,宋国兴,等.压气机插板式进气畸变实验研究[J].工程热物理学报,2018,39(3):489-496.
[10]张磊,郎进花,王松岭.电站轴流风机旋转失速工况下的叶轮静力特性研究[J].动力工程学报,2015,35(5):387-393.
[2]郎进花,楚武利,安光耀,等.跨声速轴流压气机的失速发展机理[J].航空动力学报,2018,33(8):1964-1973.
[3]薛翔,王彤,奚铭铮.离心叶轮与无叶扩压器的多相位动态测试分析[J].工程热物理学报,2018,39(9):1952-1957.
[4]刘平. 300MW机组一次风机失速案例分析及预防措施[J].电力科学与工程,2018,34(2):75-78.
[5]屠宝锋,刘华,胡骏.弓形静子提高压气机抗旋流畸变能力研究[J].航空动力学报,2016,31(8):1943-1949.
[6]高立朋,杜娟,李继超,等.带周向单槽的低速轴流压气机失速起始过程[J].航空学报,2015,36(12):3822-3831.
[7]祖红亚,李春,李润杰,等.襟翼相对长度对翼型气动性能的影响[J].动力工程学报,2015,35(8):666-673.
[8]孙鹏,傅文广,钟兢军.跨声速压气机突尖波型失速特征的数值研究[J].工程热物理学报,2018(1):76-81.
[9]周游天,李军,宋国兴,等.压气机插板式进气畸变实验研究[J].工程热物理学报,2018,39(3):489-496.
[10]张磊,郎进花,王松岭.电站轴流风机旋转失速工况下的叶轮静力特性研究[J].动力工程学报,2015,35(5):387-393.