Vibration Damping Analysis And Optimization Design Of The Reciprocating Compressor Pipeline

As fluid conveying equipment, reciprocating compressors are widely used in chemical, nuclear, ocean engineering, transportation industry and other national pillar industries. The fluid pressure pulsation occurs when the piston periodically sucks and exhales. Pipeline vibration easily happens under the fluid fluctuations which would affect the normal operation of the equipment. Besides, resonance occurs when the compressor excitation frequency is close to the natural frequency of the gas column or the pipeline which will cause great threat to the system safety. So study on the control of the pipeline vibrations and resonances is of great significance. In this thesis, theoretical derivation of the plane wave theory and the calculations of natural frequencies of the two vibrations by using finite element software were carried out. The main contributions are as follows:(1)The calculation formula of flow pressure pulsation, gas column natural frequency and resonant pipe length was summarized together with the application of the finite element method in the calculation of flow pressure pulsation. The gas column model was established with the PULS software. The modal analysis and the flow pulsation analysis were carried out to show the low order natural frequency and the pressure pulsation value.(2)Theoretical calculation of the natural frequency of pipeline was simply derived. A complex pipeline model was established with the software of CAESAR Ⅱ and stress analysis was conducted on this model. The low order natural frequency of pipeline and the gas column natural frequency of the same model were studied and compared to the compressor excitation frequency to avoid the occurrence of resonance.(3)The finite model of a single pipe support was established with the ANSYS software. The connection way of the plate to the pipe was respectively simplified to rib plate supports, contact pairs and overall simplification and the stress distributions were investigated and compared. In addition, pipe of large diameter with branches and stiffened plates were analyzed to show the function of stiffened plates in the control of vibration displacement. Methods for the control of compressor pipeline vibration were summarized.