Analysis Of Fluid-Solid Coupled Heat Transfer Of Hydro-Viscous Friction Pair And Study On Flow Characteristics During Starting Process

Hydro-viscous drive(HVD)technology has advantages of high-efficiency and energy-saving,excellent performance of speed regulation,synchronous transmission and is easy to realize automatic control;it has an extensive application prospect in large power and heavy load equipment's soft start like belt conveyors and speed regulation such as fans and pumps.Therefore,it has great significance to carry out further study on HVD technology.The analytic expressions of radial flow,pressure and bearing capacity for oil film between non-grooved friction pair have been established.The influence of dynamic viscosity,film thickness and angular velocity on radial flow and the influence of angular velocity on pressure and film bearing capacity are analyzed.Distribution law of flow and film pressure along radial direction is obtained.On the basis of hydrodynamic lubrication theory,the analytic expression of dynamic bearing capacity for grooved friction is derived.According to the law of Newton internal friction,the analytic expressions of transmitted torque for non-grooved and grooved friction pairs are established and the influence of film viscosity,thickness and angular velocity on transmitted torque is analyzed.Designed multiple sets of radial groove friction pairs with different groove sizes and the 3-D physical models was established and meshed.The models are analyzed by using software FLUENT in numerical simulation with the consideration of viscosity-temperature relationship of working oil.And obtain the distribution law of film bearing capacity,transmitted torque,temperature field and pressure field,by comparing the influence of different groove size on the HVD characteristics,put forward reasonable proposals about size design of radial grooves for friction disks.In addition,the results of the thermal fluid-solid coupling and heat flow coupling of the friction pair are compared by simulation method,and the advantages and disadvantages of the two methods are analyzed.The results show that the distribution patterns and trends of the two coupling modes in the pressure field and temperature field are roughly the same,Coupling methods similar size resulting pressure values,temperature values of heat flow method of coupling about 10% higher than the solid coupled heat.Based on the heat flow coupling method,the liquid-viscous drive start-up process is studied under the premise of considering the viscosity-temperature characteristics of the work.The variation law of working oil transmission torque,oil film temperature field and pressure field under the condition of pure oil film stage under the conditions of parallel interface and deformation interface is analyzed..The difference between the flow field characteristics of the pure oil film stage in the starting process of the parallel interface and the deformed interface was compared..HVD experimental device is built and the experimental research on radial grooves is developed,based on the results,the distribution law of transmitted torque,pressure field and temperature field between friction disks are obtained.The experimental results approximately agree with the theoretical analysis results and the reliability of theoretical analysis is proved.The research results have guiding significance in the thorough research of HVD technology,and provide technical support for the design of HVD.