Simulation And Analysis Of Wet Friction Based On Computational Fluid Dynamics

Wet dual clutch automatic transmission provide the high transmission efficiency, compact configuration and low weight of the conventional MT and have the seamless shifting and good fuel economy of an AT. Time spent researching on wet dual clutch in our country is very short, and we are still being the stage of learning and exploring. But as reform and opening up is gone further, the development of the auto industry develops faster and faster. So we can research the wet clutch more deeply with the support of the foreign technology, and supply more reference for our independent research and development of automatic transmission.The thesis is based on the development project of Jilin science and technology—"vehicle key technology (Jilin automobile independent innovation joint action)". Jilin science and technology hall entrusts Jilin University with the key technology of DCT. This thesis mainly presents internal flow field of three kinds of special groove, convective heat between the disc and plate and drag torque according to the DCT project. The thesis Is divided into five parts:In the first chapter, we can reveal the working situation of the wet dual clutch by presenting the configuration and operational principle of the clutch.The second chapter mainly introduces the calculation model of the flow field and convective heat based on fluid mechanics. Cooling oil in the wet clutch can be thought of as a kind of 3d transient irregular turbulent flow with rotation. The flow calculation of the model is to solve the discretization equation of variables. Failure modes of the friction disc are mainly deformation and cracking or ablation caused by high temperature, because of the sliding between the friction disc and steel plate. The convective heat between the cooling oil in the grooves and the discs is the important point of the thesis.The third chapter describes the process of building the simulation model. Use 3d drawing software UG to create the configurations of special grooves. Then import the 3d model into Gambit program to simplify the model and divide grids after the relative setup, such as element type, grid type, boundary conditions and so on. At last import the good mesh file into CFD to get on the simulation.The forth chapter presents internal flow field and convective heat simulations of the three kinds of groove—radial, square, radiation of the sun, using CFD program. Depending on the results of velocity magnitude and temperature of the simulations, one can compares the three kinds of grooves on the quality of the internal flow field.In the fifth chapter, the authorized disc manufacturer produces friction plates and performs the bench tests domain with the rotate speed or the speed of input oil. Collect the data of the tests and compare the result with the simulation. As a result, the simulations coincide with the experiments. Therefore, the data result getting from the simulations of the wet clutch using fluid mechanics program has high reference value.At last, summarize the thesis. This part presents the difficulties and important sections experienced during the thesis work, and points out the unsatisfactory side, and figures out the direction of the further research.