Reciprocating Compressor Pipeline Fault Diagnosis And Vibration Reduction Research Based On The Modal Analysis

In petrochemical enterprises, reciprocating compressors are widely used for gas compressing. Due to the uniqueness of the movement mechanism, they cause the vibration of the exhaust pipe in operation easily, and creat great threat to the safety of the enterprises. Based on this situation, this paper will use modal analysis method which was widely used in the automotive, aerospace, household appliances, construction and other industries to research structure fault diagnosis of reciprocating compressor exhaust pipeline and the method of pipe vibration reduction through the theoretical research and experimental exploration. The main task and research results are as follows:At the present stage there are many article making research on reciprocating compressor piping vibration, but few research has been made on the systemic arrangement of vibration mechanism and the vibration reduction method, this paper sums up a set of complete mechanism of reciprocating compressor piping vibration, its defining ways, and the methods of vibration reduction suitable for the corresponding vibration source.This paper researches the definition, classification, parameter identification method of modal analysis, and the theoretical basis that this paper needs. The paper analyzes application situation that the three methods of modal analysis on the reciprocating compressor piping vibration, and their respective advantages and limitations. The paper studies how to get the modal parameters of the piping system by modal parameter identification using the three methods of modal analysis and how to determine the causes of piping vibration. Merging three kinds of modal analysis methods to find out a way to change the natural frequency of the pipeline by changing the mass, stiffness and damping.To establish the exhaust pipeline model and calculate the modal parameters of the exhaust pipe using Autopipe finite element analysis software. To compare it with the result obtained by experimental modal analysis and operational modal analysis to verify the results of the two, and use the results of the two to guide the finite element model modification. Pipeline structure modification is simulated after finite element model has been perfected. Use the other measures for vibration reduction such as change the support position and add support or damping in a specific location to observe variation of each modal parameter without changing route and length, and finally to achieve the effect of vibration reduction.Experimental modal analysis and operational modal analysis are taken on the exhaust pipe through data collection machine and professional modal analysis software. The modal parameters are got based on vibration response and are compared with the results of the finite element analysis to determine the final modal composition and guide the finite element modification. To deduce the influence of the changing of the modal parameter on the structure parameter (mass, damping, and stiffness) based on operation deflection shape analysis to determine where and how to change the structure can be the most effective measure to make the pipeline natural frequency avoiding the input force frequency. Then made the modification simulation on the finite element structure and made vibration reducing modification on the exhaust pipe.