## 1 Introduction  
As a core component of mechanical transmission systems, bearings are widely used in aerospace and other fields, and their reliability is highly dependent on lubrication. However, in the complex working conditions in aerospace and other fields, traditional lubricants as a lubricating medium inevitably encounter high temperature conditions leading to a reduction in viscosity and seriously affecting the lubrication effect of the bearings. In the case of journals operating at high speeds, the pressure of the lubricant is much higher than the external pressure, resulting in end drains and the need to continuously refill the bearing with lubricant, resulting in a cumbersome operation and waste of resources. Magnetic fluids can be used to prevent the loss of lubricant by providing directional lubrication in a fixed field [1, 2], at the same time, by adjusting the magnetic field strength, the viscosity of the magnetic fluid will also change [3, 4], which can regulate the change in viscosity due to environmental factors such as high temperatures and achieve active lubrication. Magnetic fluids are new smart materials with superparamagnetic properties formed by the homogeneous dispersion of magnetic nanoparticles attached to surfactants in a carrier fluid. Because of their unique rheology and controllable advantages, they are used in areas such as damping, vibration damping and rotation [5; 6; 7]. The unique rheology of the magnetic fluid has brought ideas to researchers at home and abroad to design new magnetic fluid lubricated bearings. [PERSON] et al. [8] investigated the dynamic and static performance of long journal bearings lubricated with magnetic fluids compared to conventional lubricants using journal rotation and translation, and found that bearings lubricated with magnetic fluids had a lower coefficient of friction and higher load carrying capacity. The rheological properties of magnetic fluids can respond rapidly to changes in the magnetic field and have promising applications in active lubrication [6]. Its unique rheological properties have given domestic and international researchers ideas to design new magnetic fluid lubricated bearings. [PERSON] et al. [9] proposed a composite fluid-lubricated hydrodynamic bearing that could control the performance of the bearing by varying the magnetic field strength. It was found that the magnetic field strength increased, the magnetic fluid oil film carrying capacity increased, and the journal moved towards the center of the bearing, improving the reliability of the bearing. [PERSON] [10] investigated the effect of frictional sub roughness on magneto-fluid lubricated disc extrusion oil film bearings, and found that porous annular disc extrusion bearings with high roughness had greater load carrying capacity and better bearing performance. [PERSON] et al. [11] proposed a magnetorheological fluid lubricated floating ring bearing and tested the vibration suppression effect of the bearing under the action of an applied magnetic field using a magneto rheometer, and the results showed that the magnetorheological fluid lubricated floating ring bearing has a good vibration suppression effect. [PERSON] et al. [12] used magnetic fluids and conventional lubricants in the same bearing lubrication system for a comparative performance study, which concluded that magnetic fluid lubrication has better load-bearing capacity and still has load-bearing capacity for journals under magnetic fluid non-flow conditions. [PERSON] et al. [13] used software simulations and experimental verification analysis to conclude that the use of magnetic fluid lubrication can significantly improve the performance of hybrid journal bearings. [PERSON] et al. [14] designed a hydrodynamic radial bearing based on magnetic fluid lubrication. A comparative analysis with conventional lubricants showed that the magnetic fluid lubricated bearing has a higher load carrying capacity, lower temperature rise and significantly improved bearing performance. [PERSON] et al.