Flow Characteristics Of Graphene As A Lubrication Additive In High-speed Motorized Spindle Bearings

Bearing oil-air lubrication is a widely used lubrication technology in recent years,but under high-speed rotation,problems such as uneven lubrication and temperature rise will also occur.In order to improve the lubricating effect of bearings,the use of graphene as a lubricating oil additive is a new way to make full use of graphene lubrication and antifriction performance in that it can solve the above problems.However,the distribution of graphene particles in the bearing cavity directly affects the temperature rise of the bearing.Therefore,it is necessary to accurately analyze the flow characteristics of graphene as a lubricant additive in high-speed motorized spindle bearings.Based on the multiphase flow theory and heat transfer theory,a multiphase flow model and temperature field model in the B7003 CY / P4 angular contact ball bearing cavity are established.The distribution of air,lubricating oil and graphene in the bearing cavity and the effect on the bearing cavity are analyzed.The specific research work is as follows:(1)The Euler-Euler model was established on the basis of the theory of multiphase flow and heat transfer.The speed of the gas was considered in the bearing cavity,and the distribution of lubricant was analyzed.The temperature field distribution in the bearing cavity was analyzed by calculating the frictional heat generation of the bearing and the heat transfer coefficient of the key points in the cavity.Calculated the air flow velocity,pressure and lubricant distribution in the bearing cavity at the speeds of 6000 r / min,12000 r / min,18000 r /min,24000 r / min and 30000 r / min.The simulation results showed that the rotation speed affects the distribution of the lubricating oil.As the rotation speed increased,the distribution of the lubrication oil in the bearing cavity was more uniform.The temperature in the bearing cavity was affected by the rotation speed of the motorized spindle.As the rotation speed of the motorized spindle increased,the temperature in the bearing cavity increased and the temperature field in the bearing cavity was refined after the temperature field.(2)The speed and the graphene content were taken into consideration to analyze the distribution of graphene in the bearing cavity,and the temperature field at the gap between the ball and the inner and outer rings.The simulation results showed that graphene flowed through the oil pipeline and was affected by the air velocity.It spreaded out at the front end of the bearing cavity,and the flow velocity near the ball became larger,which accelerated the distribution of graphene in the bearing cavity.After passing through the balls,the velocity of the airflow was reduced,causing graphene to adhere to the entire bearing cavity wall.Thegraphene content on the temperature field in the bearing cavity was explored and the verification that the addition of graphene in the lubricating oil was simulated to verify the effect which can reduce the temperature rise of the bearing.Added 0.005%,0.01%,and0.015% graphene additives to show that the addition of 0.01% graphene additives in lubricating oil which can best achieve the effect of reducing bearing temperature rise.(3)The temperature rise test bench for motorized spindle bearings was established.The temperature signal acquisition instrument and temperature sensor were used to measure the outer ring temperature of the motorized spindle bearing.The test results with the graphene additive and without graphene additive were added to the lubricating oil to measure separately,and the simulation results were basically matched.The ambient air quality detection platform was established to analyze the atomization characteristics of praphene lubrication.The effects of rotation speed,graphene content,and gas supply pressure on the atomization characteristics of graphene lubricants were revealed.The proportion of oil mist particle diameter less than or equal to PM2.5 and oil mist particle diameter less than or equal to PM10 was detected.The test results showed that the effect of graphene lubricating oil on the ambient air quality was smaller than that without graphene lubricating oil.