A numerical model to predict film torque of hydro-viscous clutch was developed.The model was established with computational fluid dynamics（CFD）.The pressure distribution,velocity of flow and film torque were obtaine...A numerical model to predict film torque of hydro-viscous clutch was developed.The model was established with computational fluid dynamics（CFD）.The pressure distribution,velocity of flow and film torque were obtained based on vertical-horizontal grooved plate and radial grooved plate separately.The boundary conditions,such as the relative rotation,the fluid temperature and the oil feeding pressure,were also discussed.The results showed that the film torque of two kinds of grooved plate increased with increasing relative rotation.However,the film torque decreased with increasing fluid temperature and feeding pressure.Meanwhile,the film torque of radial grooved plate was less than vertical-horizontal grooved plate at the same condition.Our study showed that the model can efficiently calculate the film torque with complex geometry parameters and boundary conditions.展开更多
The 5754 aluminum alloy has been widely used in the automotive industry to reduce the weight of vehicles.The weld-bonding(WB)process comprising resistance spot welding and adhesive bonding processes effectively improv...The 5754 aluminum alloy has been widely used in the automotive industry to reduce the weight of vehicles.The weld-bonding(WB)process comprising resistance spot welding and adhesive bonding processes effectively improves the mechanical properties of joints.However,it is still a great challenge in the WB process to obtain high-quality and defect-free nuggets of aluminum alloys.In this study,the parameters of the WB process are optimized and the mechanism of generation of defects during WB is analyzed.The results show that the welding parameters have a significant effect on the nugget sizes,among which the welding current plays the most important role.The residual adhesive can easily cause defects during welding,e.g.,expulsion and porosity in the nugget.This can be effectively avoided by optimizing the welding parameters.In addition,the gas in the joints is effectively reduced by adding an appropriate preheating pulse prior to welding,thus lowering the damage degree of the adhesive layer.As a result,welded joints with better weld nugget quality and more stable mechanical properties are obtained.展开更多
基金Supported by the National Natural Science Foundation of China(51275039)
文摘A numerical model to predict film torque of hydro-viscous clutch was developed.The model was established with computational fluid dynamics（CFD）.The pressure distribution,velocity of flow and film torque were obtained based on vertical-horizontal grooved plate and radial grooved plate separately.The boundary conditions,such as the relative rotation,the fluid temperature and the oil feeding pressure,were also discussed.The results showed that the film torque of two kinds of grooved plate increased with increasing relative rotation.However,the film torque decreased with increasing fluid temperature and feeding pressure.Meanwhile,the film torque of radial grooved plate was less than vertical-horizontal grooved plate at the same condition.Our study showed that the model can efficiently calculate the film torque with complex geometry parameters and boundary conditions.
基金The authors gratefully thank the financial support from Excellent CAS Talents(NO.292017312D1100301)Excellent Technology Leader(NO.19XD1433500)Strengthen Industrial Base(GYQJ-2019-1-33)programs,which are from Chinese Academy of Sciences,Science and Technology Commission Shanghai Municipality,and Shanghai Municipal Commission of Economy and Information,respectively.
文摘The 5754 aluminum alloy has been widely used in the automotive industry to reduce the weight of vehicles.The weld-bonding(WB)process comprising resistance spot welding and adhesive bonding processes effectively improves the mechanical properties of joints.However,it is still a great challenge in the WB process to obtain high-quality and defect-free nuggets of aluminum alloys.In this study,the parameters of the WB process are optimized and the mechanism of generation of defects during WB is analyzed.The results show that the welding parameters have a significant effect on the nugget sizes,among which the welding current plays the most important role.The residual adhesive can easily cause defects during welding,e.g.,expulsion and porosity in the nugget.This can be effectively avoided by optimizing the welding parameters.In addition,the gas in the joints is effectively reduced by adding an appropriate preheating pulse prior to welding,thus lowering the damage degree of the adhesive layer.As a result,welded joints with better weld nugget quality and more stable mechanical properties are obtained.
