Fluid Dynamic Simulation And Oil Way Optimization Of Wet Multi-plate Friction Clutch

Wet multi-plate friction clutches are widely used in marine transmission system forits small value, high transmission torque, easy control, reposeful starting and smoothreversing. As clutches in marine gearbox are assembled in pair, when one is engaged,the other is in disengaged operation, where the relative velocity between friction disksand steel disks will be twice. If they cannot separate absolutely, the temperature causedby oil shear will rise quickly in those smaller clearances, thus overheating problemoccurred. Therefore, it has important theory significance and great engineering values inthe reduction of overheating failures to conduct a research on fluid dynamic simulationof disks separating process, thermal-fluid analysis and optimization of oil way in theclutch.The topic of this thesis is supported by Key Science and Technology PlanningProjects of Chongqing. A research on disks location simulation and oil way optimizationof wet multi-plate friction clutch will be carried out in the thesis. The research work inthis thesis can be summarized as follows:1) Taking the structure and operating conditions into consideration, theparameterized finite element model of oil way is built in ANSYS/CFX with movingboundaries derived from transient motion equations of the disks. A dynamic simulationof the oil way in disks separating process is conducted with moving mesh technology.Then the disks location can be obtained. After that the influence of inlet flow on disksseparating process and disks location is explored and proposed.2) Taking the effect of oil viscosity-temperature characteristic and oil film shear onthe energy conservation equation into consideration, the thermal-fluid analysis isconducted with the real oil way gained before as the study object. Afterwards the effectof inlet flow on oil temperature is investigated by CFD method and compared with thetest result.3) The parameterized finite element model of oil between friction disk and steeldisk is established with the consideration of spiral and radial oil groove. Afterthermal-fluid analysis, the pressure, velocity and temperature distribution on the surfaceof friction disk is achieved. The influence of oil film thickness and groove parameterson oil temperature is discussed eventually.4) Taking the diameter and location of squirt holes as design variables, the maximum and minimum pressure of the clutch as constraint conditions, and the RMSvalue of forces on disks as the objective function, an optimization model of the oil wayis created through ANSYS/Workbench. The best structure of oil way is attained byresponse surface optimization method.