The Vibration Isolation Design And Analysis Of A 5L21/31 Marine Diesel Generator Set

The vibration of the marine diesel generator set directly affects the performance of the machinery and equipment.The vibration of the marine diesel generator set may not only destroy the structural strength and cause structure noise,but also worsens the working condition of varieties of instruments and sensitive device,reduces the measurement accuracy of instruments and sensitive device.It may influence the comfort of the ship.A variety of effective damping and anti-vibration measures has been widely used,with the development of the research about the diesel.In this article,5L21/31 diesel generating sets of a marine are used for the study.Firstly,piston assembly,connecting rod and crankshaft three-dimensional solid model are built in the three-dimensional modeling software Pro/E,crank linkage kinematics and dynamics simulation analysis is done,then,the major excitation and the corresponding harmonic times force causing unit vibration is gotten by the integrated use of kinetic theory.Secondly,the isolation system is preliminary designed on the base of work status and experience of the unit.The general process and points of isolator selection and arrangement are described.This isolation system natural frequencies and mode shapes of the unit is gotten by establishing the overall model of diesel generator sets and using analytical solution and the finite element means to the calculation and analysis of unit modal respectively.The merits of two calculation methods are comparative analysis by combining with the results given by the company of the world’s leading isolator design manufacturers of Rubber.Most of the major critical speed units are less stable speed by the map of power unit natural frequency and scrambling critical speed.It’s means that the rated speed operations completely avoid the main resonance region and vibration isolation system designed to meet the requirements.The five three-point direction of the main unit of observation frequency amplitude curve obtained by using finite element calculation of vessel response means diesel generator sets in each of the disturbance vibration excitation under the design of vibration isolation system.Disturbance excitation resonance point at each unit and vibration intensity is analyzed,the response of unit at rated speed conditions is extracted,The vibration amplitude of each isolator is key observed.Isolation system is further evaluated.The stability of the unit is checked in the condition of boot,the parking process,ship heeling,and trim state.In this paper,after taking the vibration isolation system as the above program there sets avibration test for the five-cylinder marine diesel generator.Based on the measured data,we can calculate the velocity intensity level of this type of the marine diesel generator.And compared the velocity intensity level the national standard.From the comparative,we can see that the calculated velocity intensity level reaches the A/B-level of GB.The diesel generator vibration isolation system has a good effect,which has been verified finally.