Flow Field Characteristics And Surface Micro Texture Lubrication Characteristics Analysis Of Elliptical Bearing

With the development of rotating machinery in the large-scale and high-speed direction,the application requirements of mechanical equipment for bearings are higher and higher.As an important supporting part of rotating machinery,the working condition of oil film bearing directly affects the stability,working accuracy and other technical indicators of rotating machinery.Elliptical bearing has a double wedge oil film structure,which can effectively suppress the whirl trend of shaft diameter.The stability of elliptical bearing is better than that of cylindrical bearing,and it is widely used in large rotating machinery.The flow field characteristics of oil film bearing decide whether the rotating machinery has enough bearing capacity to balance the external load,which is the key to maintain the safe and stable operation of mechanical equipment,so it is very important to study the flow field characteristics of elliptical bearing;at the same time,the research on the tribological performance of micro texture oil film bearing can provide new ideas for the design of oil film bearing,so as to improve the overall performance of oil film bearing.Therefore,the paper takes elliptical bearing as the research object and uses Fluent software to calculate and analyze the flow field characteristics of the bearing under different working conditions and micro texture geometric parameters.The specific research contents are as follows:Firstly,the physical models of cylindrical and elliptical bearings are established,and the oil film pressure distribution of cylindrical and elliptical bearings is simulated,and the oil film pressure characteristics of the two bearings are compared and analyzed,and the conclusion is that the stability of elliptical bearings is better than that of cylindrical bearings.Secondly,the flow field characteristics of the oil film of the elliptical bearing under different ovalities are compared and analyzed.The results show that when the ovality is less than 0.5,the elliptical bearing can not form a complete double oil wedge oil film structure;when the ovality is 0.5～0.7,the upper and lower pads of the elliptical bearing can form an effective bearing oil film,which can effectively restrain the whirl trend of the shaft diameter and ensure the stability of the bearing system;when it is greater than 0.7,the oil film in the main bearing area of the elliptical bearing is relatively short and the friction resistance is too large,which is easy to cause the instability of the oil film.Thirdly,the influence of different working conditions on the flow field characteristics of oil film of elliptical bearing is analyzed.The results show that with the increase of journal speed,lubricant viscosity,width diameter ratio and eccentricity,the oil film pressure increases,the bearing capacity increases,and the cavitation area expands;with the increase of oil inlet pressure,the oil film pressure increases slightly,the bearing capacity increases slightly,and the cavitation area shrinks.Finally,the influence of the arrangement position,working condition,geometric parameters and shape of the micro texture on the lubrication performance of the micro texture bearing is analyzed.The results show that the arrangement of the micro texture near the extreme value of the positive pressure of the oil film is more conducive to the improvement of the bearing capacity and the reduction of the bearing friction coefficient;the proper increase of the journal speed and the viscosity of the lubricating oil is conducive to the improvement of the bearing capacity and the reduction of the friction coefficient.Compared with the hemispherical and trapezoidal micro texture,the rectangular and triangular micro texture is more conducive to improve the bearing capacity and reduce the friction coefficient of the bearing.