Research And Simulation Of Wet Multi-disc Clutch Towing's Characteristics

The source of the project is “analysis of CODOG transmission system simulation”scientific research of CSIC 703 institute.Since the wet friction clutch is an important part of ship transmission system,the performance of clutch has important influence on safety and reliability of the ship power system.The oil must be full of the friction plate gap to ensure the normal operation of wet friction clutch.The oil has functions of cooling and lubrication.According to the characteristics of wet friction clutch,the phenomenon of drag torque is the inherent disadvantage.Drag torque turns to be inevitable as long as oil film exists in the clutch,so it is necessary to analyze and research the phenomenon of wet friction clutch drag torque.According to the research status of wet friction clutch,the calculating model was established and different factors' influences on drag torque were analyzed.There is coupling relation between temperature and radius in practical operation of the clutch.Through the decouple simulation of temperature field,torque calculation model was improved.Finally the model was verified by CFD simulation.The main research contents are as follows:First of all,the calculation model of single oil film torque was established via theory analysis.The domestic and overseas status quo of drag torque and thermal characters were outlined.The geometric model of single oil film was established for wet multi-disc friction clutch based upon Newton inner friction law.Secondly,the whole clutch torque calculation model was established by analyzing sliced interval of the clutch.There was a conclusion that the oil film force is far greater than the axial friction through computing the continuous oil film characteristic equation.Clutch friction plate is regard as distributed uniform in theory,which is not identical with that in the experiment.Experimental results reveal that the friction plate gap of intermediate thickness is about 1.2 times the thickness at both ends.The whole clutch torque calculation model was deduced and the coupling relationship between radius and temperature has been verified.Thirdly,the coupling relation between radius and temperature was analyzed through simulation of the clutch's temperature field.The principle of wet friction clutch temperature rising was studied.Through the solution of the convection heat loss problem of the body in high-speed rotation and the rotating parallel plates' convective heat transfer problem,the convective heat transfer coefficients were obtained in different conditions and motion states.The relationship between the radius and temperature was obtained from the clutch temperature simulation.Through the relation decouple,torque calculation model was improved and compared with the original model.Finally,the CFD simulation and the theoretical model were compared.According to the wet friction clutch,torque simulation model was established and the meshes were meticulous divided in CFD.The RNG k-? model was adopted as the turbulent model and parameters were set up.Thus the drag torque under different conditions was calculated and comparative analysis on the results was conducted.In the end,software of calculating drag torque was developed.