秸秆抛送装置抛送叶轮的振动特性分析  

Analysis on vibration characteristics of throwing impeller of stalk impeller blower

作　　者：翟之平[1] 周雷[1] 杨忠义[2] 赵艳琼[1] 甘世明[1] 

机构地区：[1]内蒙古工业大学机械学院,呼和浩特010051 [2]内蒙古工业大学教务处,呼和浩特010051

出　　处：《农业工程学报》2015年第4期17-25,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51165025);内蒙古自然科学基金资助项目(2014MS0512)

摘　　要：针对叶片式秸秆抛送装置工作时的振动、噪声以及叶片疲劳断裂等问题,为减少共振的发生,利用有限元分析软件ABAQUS对抛送叶轮的自由模态与预应力模态进行了数值计算,其中预应力模态采用单向流固耦合方法对流场和叶轮结构响应进行求解,获得了该系统的前12阶模态频率以及振型,并利用扫描式激光测振仪对抛送叶轮进行了模态试验,验证了理论分析和数值计算的准确性。在分析了系统外部激振频率特点的基础上,对影响叶轮振动特性的结构参数进行了对比模拟。研究结果表明:预应力使叶轮的1和2阶频率提高幅度较大,对振型没有影响;叶片数对模态频率和振型影响最大,叶轮是否加筋对频率的影响其次,叶片厚度对低阶频率影响最小;三叶片叶轮最不易发生共振,四叶片次之,五叶片最易发生共振;叶片厚度为4 mm时最不易发生共振,5 mm时次之,6 mm时最易发生共振;叶轮加筋可以改善其动态性能,不易发生共振。该研究可为叶片式抛送装置结构振动特性的描述及动态性能的优化提供参考。An impeller blower mainly consists of throwing impeller, shell, discharge tube, etc. When the impeller blower is working, the material is transported by mechanical centrifugal force and airflow which are generated by a high-speed rotating impeller. As the core component of the impeller blower, the impeller have to bear the comprehensive effect of the centrifugal force, the pressure of high-speed air flow inside the impeller blower and impeller gravity, which may produce violent vibration. The vibration will not only accelerate the throwing blade＇s fatigue fracture and affect its service lifetime but also produce environmental noise. In the meantime, if the excitation frequency is closed to some-order natural frequency of the throwing impeller, the whole device would produce resonance which seriously affects the work performance, the service life and reliability of the impeller blower. Therefore, in order to improve the working performance of impeller blower and avoid the resonance, it is quite important to analyze the vibration characteristics of the throwing impeller. In this paper, the modal frequency and vibration types of the first 12-order free modal and constraint modal were calculated using the finite element analysis software ABAQUS. In order to verify the accuracy of numerical calculation, a modal test of the impeller was carried out using the PSV-500-3D Scanning Vibrometer, which showed the maximum error of numerical modal frequencies and experimental modal frequencies was 8.5%, the vibration types were basically the same, and the numerical calculation results were reliable. Based on analyzing the characteristics of external excitation frequency, the structural parameters such as blade number, blade thickness, whether reinforcement were simulated and compared. The results show that： 1） Prestress increased each order natural frequency of the impeller, and only the first and the second order frequency increased largely while other frequencies increased a little. Prestress has no impact on the vibrat

关 键 词：农业机械 振动 有限元法 抛送叶轮 模态分析 模态试验 

分 类 号：TH232[机械工程—机械制造及自动化]