| The silicone oil fan clutch is a mechanical device that uses silicone oil fluid as the working medium and uses the viscous shear force of the silicone oil to transmit torque.It can adjust the cooling intensity of the engine at any time according to the thermal condition of the engine,reduce the power loss of the engine,increase the service life of the engine,improve the economy of the engine,and has broad application prospects.In this thesis,the slip of silicone oil fan clutch is analyzed and studied by CFD method and experimental method.Based on a threedimensional solid model of a double-sided grooved silicone oil fan clutch,considering the influence of the thermal balance and torque balance during the working process on the slip,a CFD numerical calculation model for solving the clutch slip is established,and a complete numerical calculation process was proposed.The main work contents of the thesis is as follows:(1)The viscosity-temperature characteristic curve of silicone oil was measured.A 4000 c St silicone oil was used for viscosity measurement,and combined with the viscosity-temperature curve model of the silicone oil,the dynamic viscosity-temperature characteristic curve of the silicone oil was determined,which will used for the CFD numerical calculation on the slip of silicone oil fan clutch in Chapter 4.(2)A silicone oil fan clutch slip experimental bench was established,and the clutch slip and cooling fan performance were tested on the experimental bench.A D90-CP double-sided grooving silicone oil fan clutch was used to carry out slip test on the experimental bench to obtain the driven plate speed and temperature data under different driving plate speeds,which provide comparative verification for the CFD numerical calculation results of the slip of silicone oil fan clutch.A Z680W-11 D cooling fan was used to carry out performance test on the experimental bench to obtain the output speed,flow,torque data.According to the fan law,the flow-speed data and torque-speed data are fitted with linear polynomial and quadratic polynomial respectively to obtain flow-speed characteristic curves and the torque-speed characteristic curves of cooling fan,which will used for the CFD numerical calculation on the slip of silicone oil fan clutch in Chapter 4.(3)Based on a three-dimensional solid model of a double-sided grooved silicone oil fan clutch,when the driving speed is taken as a fixed speed,considering the influence of torque balance and thermal balance on slip,a CFD numerical calculation model and a set of complete calculation process of the slip of silicone oil fan clutch are established.The CFD numerical calculation method is used to calculate the slip results under different driving speeds respectively.Comparison between the CFD results and the test results shows that the two are in good agreement,which verifies the CFD calculation method of the slip of silicone oil fan clutch in this thesis.A CFD numerical method for calculating the slip of silicone oil fan clutch is proposed in this thesis.When extending the slip calculation of silicon oil fan clutch to the related problems of the slip calculation of hydro-viscous drive(HDV)friction pair,if the geometric structure of the working cavity is complex and irregular,the geometric size is difficult to measure,or the spatial shape of the working cavity is ever-changing in the working process,it is difficult to establish an accurate mathematical model using theoretical calculation methods.By using CFD numerical calculation method in this thesis,only need to establish a CFD numerical calculation model that is consistent with the actual working cavity structure of hydro-viscous drive,the above problems can be solved smoothly,and the slip solution of hydro-viscous drive can be solved,which has certain engineering application value. |
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