Study On Numerical Simulation And Vibration Sysnoise Analysis Of Roots Blower

Dynamic analysis of mechanical system and the simulation of structure noise is an important domain of vibration and noise control research. This issue was based on the foundation of Shandong province natural science (Y2006F38) which is Roots Blower Noise and Vibration Source Identification and the research of prediction model. The engineering research background of this issue is the control of roots blower vibration and noise. The rotor system, shell and whole roots blower were researched and analized about dynamic characteres using dynamic substructure method. Besides, the structural noise of fan shell was predicted and numerical simulated in the method of both the finite element method and boundary element method. This issue was helpful for the theoretical of structural dynamic modification and low noise design of roots blower.The main contents of this issue are as follows:(1) The situation about the dynamic characteristics analysis and the noise numerical simulation of mechanical structure was summarized at first. Foundational theory of dynamic analysis and noise were summerized and the general steps of dynamic analysis were showed. And then computation flow chart of mechanical vibration noise acoustical field were established, giving the process of solving vibration noise radiation problem using boundary element analysis software.(2) According to the structural character of roots blower, the finite element dynamic model of rotor system, shell and whole roots blower were established in the ANSYS software. The whole systerm and substructures of it were analized in model using finite element method and dynamic sub-structure method. And then the inherent frequency and inherent vibration figure of the rotor system, blower box and the whole system were obtained. So the coupling vibration situation of the whole roots blower system can be understanded clearly.(3) The substructures of roots blower were analyzed in the aspect of statics, based on which vibration response of the fan shell was analized in the ANSYS software. Besides the vibration feature of fan shell and the amplitude-frequency responsing curve of the key points were obtained.(4) Boundary element mode of the acoustical field around the fan shell was established. And noise radiation around the fan shell was analized using finite element method combined with boundary element method. Boundary conditions of acoustic mode was obtained on the base of vibration responsing analysis of the shell. Acoustic filed around the fan shell was analized in software SYSNOISE.