Investigation Of Gas Pulsation And Pipeline Vibration Of Large Type Reciprocating Compressor

As a general machine of fluid compression and power delivery,compressor always been regarded as the core equipment of the petrochemical industry.Whether safe and smooth operation is directly related to the economic interests of the related enterprises.The inlet and exhaust process of piston compressor is intermittent,which makes the parameters of the air flow in the inlet and exhaust pipes change periodically,and then the flow pulsation occurs.Airflow pulsation can cause pipeline vibration easily,which leads to lower volumetric efficiency of compressor and the increasing of power loss etc.Therefore,it has great significance to study the mechanism of pulsation and its' influence on the vibration characteristics of pipeline.In this paper,the pressure pulsation of valve cavity and the vibration of pipeline are studied as follows.First,we established the mathematical model of pressure fluctuation in valve chamber.The influence of valve chamber,valve motion and pipeline system on the flow pulsation are considered synthetically in this model,which makes the compressor and pipe system formed integrally,and this kind of air flow pulsation analysis combined with compressor working characteristics will make the calculation results more accurate and closer to the actual situation.According to the simulation results of compressor work and the motion law of valve plate,we compared and analyzed the influence of with or without valve cavity,the rsults show that if we take into account the valve cavity,the speed of valve plate impact lift limiter is increased by about 10%,and the valve plate is easily damaged.After that,we discussed the influence of valve structure parameters such as valve plate lift,spring stiffness and valve blade mass on valve motion and cylinder pressure.By solving the pressure fluctuation model of the valve cavity,the pressure variation of the inlet valve cavity is obtained,and the pressure inhomogeneity is 3.49,which is within a reasonable range.Last,we studied the influence of pressure,wall thickness and inner diameter on the natural frequency of the pipeline based on the basic theory of fluid-solid coupling and modal analysis.After the modal analysis of the gas column in the pipe was carried out,based which numerical analysis of the vibration response of the pipe was done when the gas in the bend is in an unsteady state.At the same time,the influence of the frequency and amplitude of the pulsating fluid on the pipeline response is also studied.We found that the pressure pulsation causes the pipeline stress to fluctuate greatly(7%),which is easy to destroy the pipeline,and the fundamental frequency of the pipeline increases with the increase of the pressure pulsation frequency under the action of fluid-solid coupling.When the fundamental frequency of the pipeline or the fixed frequency of the gas column is close to the pulsating frequency of the gas flow(resonance),the deformation of the pipeline increases 2-3 times as much as that of the non-resonance case.