摘要
针对某振动较剧烈的水轮机,通过数值计算模拟水轮机叶轮附近压力脉动情况,并以此为边界条件计算水轮机的振动固有模态,分析其自身结构与异常振动的关联性。研究表明,水轮机运行时,水体压力脉动频率主要集中在24.5和49 Hz附近,即其叶轮通过频率的一倍频和二倍频,尤其是在叶片角度大于0°时,而水轮机叶轮模态分析所得的前2阶固有频率也在49.0 Hz附近,压力脉动频率和水轮机叶轮固有频率具有一定的相似性,因此容易引发共振,这也是该电站水轮机在叶片角度较大时振动较激烈的主要原因。
The 3D flow filed of turbine is calculated based on the Navier -Stokes equations and k - turbulence model, and the simulation results not only are beneficial to analyze the pressure pulsa- tion around turbine impellers, but also provide the boundary conditions for modal analysis of turbine rotors. And then the intrinsic mode is simulated to research the relationship between rotor structure and rotor abnormal vibration based on the modal analysis. The research results show that, the fre- quency of pressure pulsation mainly concentrated in 24. 5Hz and 49. 0Hz, especially when the blade angle of turbine is greater than -2°; the nature frequencies of first order modal and second order mo- dal are closely to the same 49. 0Hz, so it is easy to induce the resonance, and the resonance is an important factor which lead to the severe vibration of turbine.
出处
《水利科技与经济》
2014年第1期106-108,共3页
Water Conservancy Science and Technology and Economy
关键词
固有模态
水轮机
故障诊断
共振
intrinsic mode
turbine
fault Diagnosis
resonance
