Study Of Vibration Of The Ship Engine Fuel Oil Pipeline System

The vibration problem of ship power flow piping has a wide engineering background, isthe important influence factor of the ship engine room safety performance. As the transportcarrier for oil, water, gas and other fluid among every kinds of power equipments,complexpiping and all kinds of power equipments are linked together, the piping decorated in shipengine room, due to various piping vibration reasons seriously affect the service life of thepipe, threatening the safety of ship engine room. Therefore, this paper relates to the vibrationphenomenon of the main fuel oil supply piping in the ship building early, making thethorough analysis to the formation mechanism of flow piping vibration problem, studing thepiping vibration impact of the piping structure and internal fluid pulsation state, so as to geteffective measures to reduce the ship main engine fuel oil supply piping vibration problem.Therefore, doing the following research works: first, through the vibration test method,to study the structure inherent vibration frequency, structure vibration energy distribution ofthe piping which appear strong vibration problem, and at the same time, to study the pressurepulsation characteristics in the fuel piping, to analyses the problems causes of the pipingvibration. Secondly, through the structural dynamics simulation for piping which used thedifferent type constraint, which had the different size, to do the optimized analysis for thesemodification measures, though these to conclude the influence of the constraint ability to pipesystem natural vibration characteristics; Through the fluid simulation calculation in onedimensional, to do the optimized analysis for the piping internal fuel pressure fluctuatingcondition after the accumulator are added, to conclude the influence of the fuel pressurepulsation because of the accumulator. Finally, based on the virtual instrument technology,using the method of vibration analysis to construct the piping vibration on-line monitoringsystem, through the vibration monitoring results in a period, and formulate the vibrationwarning and alarm mechanism of the ship fuel oil supply piping in different modes.Analysising the numerical simulation and experimental measurement results: when theship piping used the simple linear feature constraint, the axial constraint ability is poor, it iseasily to appeare the axis constraints weaken or failure, such as to lead the inherent vibrationfrequency of the piping to reduce, and if the inherent vibration frequency of the piping closedto vibration excitation frequency of the engine, then it is easily to appear the piping resonancephenomenon; In the working process of the engine, fuel pressure pulsation will produce thestrong vibration excitation action to the piping; Through the use of adding the constraint intensity and overstriking line size, these can greatly enhance the axial constraint ability;Through adding the accumulator and reducingthe fuel oil pressure, these can attenuationgreatly the strength of the pressure pulsation and reduce the vibration strength of the piping;Establish the piping vibration on-line monitoring system for a certain ship navigated, andanalysis the vibration condition monitoring data of piping, got the maximum vibration valueof every point under the different monitoring models, provided the reference for theconstruction of the monitoring system of early warning mechanism.