大型振动流化床设备多物理场耦合分析

发布时间：2018-06-01 16:24

  本文选题：振动流化床 + 多物理场　； 参考：《东北大学》2014年硕士论文

【摘要】：振动流化床(Vibrated Fluidized Bed, VFB)干燥技术是近年来应用越来越广泛的工业干燥方法之一,随着工业化生产的巨大需求,振动流化床技术以其优良的干燥效果和经济效益,显示出了更广阔的应用前景。但是,在振动流化床设备应用过程中,两方面问题日渐凸显：其一,现有设备规模与生产需求相矛盾,大型设备设计困难；其二,振动流化床工作在流场、温度场、振动场的多场耦合作用下,工作环境复杂且恶劣,大型设备结构强度、刚度、稳定性评估困难。针对以上两方面难题,本论文以大型振动流化床设备为研究对象,完成了以下工作：首先,对150t/h大型振动流化床进行振动计算,得到结构振动频率、弹簧刚度和激振力等参数,建立整体框架模型；其次,利用CFD技术对建立的振动流化床模型进行流固耦合传热分析,获得该结构流场分布以及流体传热作用下的温度场分布；再次,将获得的温度分布数据加载入结构有限元模型中,对其进行结构热应力分析,获得热应力分布,分析结构薄弱部位,优化设计；最后,对结构进行加载上述温度分布及热应力载荷下的模态、谐响应和瞬态等动力学分析,观察结构在工作频率下的振动特性,评估结构在高温振动条件下的强度、刚度及稳定性。通过流固耦合传热分析,可知烟气在气体分布板处的最大流速为13m/s,平均速度为4.93m/s,满足流化设计要求；结构横梁部位的温度最高,为290℃。通过热应力分析发现,结构的拉筋位置对热应力影响很大,经过结构优化,有效地将本结构的最大热应力降低至244MPa,位置在两根边横梁与前后侧板的连接处；床体沿X方向膨胀变形最大值为9.6mm,前后侧板中间上缘外张变形总计15.8mm。通过进行加载温度分布及热应力预载荷的振动特性分析,验证了结构能够避免共振现象的发生；结构在工作状态下最大应力为253MPa,位置同样在两根边横梁与前后侧板的连接处；结构的稳态响应满足振幅设计要求,结构振动平稳。本论文研究的内容,对大型振动流化床设备的设计、优化与强度评估具有很强的工程指导意义。
[Abstract]:Vibrated Fluidized Bed, VFB) drying technology is one of the more and more widely used industrial drying methods in recent years. With the great demand of industrial production, vibratory fluidized bed technology has excellent drying effect and economic benefit. It shows a wider application prospect. However, in the application of vibratory fluidized bed equipment, two problems have become increasingly prominent: first, the scale of the existing equipment is contradictory with the production demand, and the design of large scale equipment is difficult; second, the vibratory fluidized bed works in the flow field and temperature field. Under the coupling action of vibration field, the working environment is complex and bad. It is difficult to evaluate the strength, stiffness and stability of large equipment structure. In view of the above two problems, this paper takes the large-scale vibrating fluidized bed as the research object, accomplishes the following work: firstly, the vibration calculation of the 150t/h large vibrating fluidized bed is carried out, and the parameters such as structural vibration frequency, spring stiffness and exciting force are obtained, such as the vibration frequency of the structure, the stiffness of the spring and the exciting force. The whole frame model is established. Secondly, the fluid-solid coupling heat transfer analysis of the vibratory fluidized bed model is carried out by using CFD technology to obtain the flow field distribution of the structure and the temperature field distribution under the fluid heat transfer. Thirdly, The obtained data of temperature distribution are loaded into the finite element model of the structure, the thermal stress distribution is obtained, the weak part of the structure is analyzed, and the design is optimized. The modal, harmonic response and transient state of the structure under the loading temperature distribution and thermal stress load are analyzed, and the vibration characteristics of the structure under the working frequency are observed, and the strength, stiffness and stability of the structure under the condition of high temperature vibration are evaluated. Through the fluid-solid coupled heat transfer analysis, it can be seen that the maximum velocity of flue gas at the gas distribution plate is 13 m / s, the average velocity is 4.93 m / s, which satisfies the fluidization design requirements, and the temperature of the structure beam is the highest at 290 鈩，

本文编号：1964818