## 3 Results and Discussion
### Flow Field Analysis of Magneto-Fluid Lubricated Bearings  
Given an oil film pressure of 5 MPa in the bearing, a spindle speed of 5000 rpm, an ambient temperature of 20 \({}^{\circ}\)C and four different eccentricity rates (0.2, 0.4, 0.6 and 0.8), the oil film pressure and temperature distributions were calculated using Ansys software. Set the grid to Sweet and Type to Element Size. When the eccentricity is 0.8, the minimum film thickness is 0.05 mm, and to ensure that there are two or three layers of mesh at the minimum film thickness, set the Sweet Element Size to 0.02 mm. Set Element Order to Linear and Element Size to 0.05 mm. Set the maximum energy residual value to 10\({}^{-6}\) and the number of iteration steps to 500. The magnetic fluid as a non-Newtonian fluid, the Equation (9) is compiled into the viscosity formula of the UDF as the magnetic fluid, the magnetic field strength is set to 0.4 T.  
Use an eccentricity of 0.2 as an experimental example, set the Sweet Element Size to 0.015 mm and 0.01 mm as the experimental group, and then set 0.02 mm as the control group for mesh convergence experiments. Take the position of the convergence wedge 3 mm away from the minimum film thickness point as the analysis object. Let the pressure of the experimental group be \(P\) and the pressure of the control group to be \(P_{0}\), then the error rate \(\varepsilon\) is:  
\[\varepsilon=\frac{|P-P_{0}|}{P_{0}}\times 100\% \tag{10}\]  
The following Figure 8 shows the experimental results. It can be seen from the Figure 8 that the maximum error rate does not exceed 3%, indicating that the results obtained by the Sweet Element Size to 0.02 mm are valid. Figure 9 shows the oil film pressure distribution of magnetic fluid bearings with different eccentricity. From the figure it can be seen that the oil film is separated into a high-pressure zone and a low-pressure zone in the minimum oil film thickness area, the high-pressure zone corresponds to a converging wedge, the low-pressure zone corresponds to a diverging wedge, and the high- pressure and low-pressure distribution is approximately symmetrical. The maximum pressure of the converging wedge is 5.24 MPa and the minimum pressure of the diverging wedge is 4.76 MPa when the eccentricity is 0.2. As the eccentricity increases, the pressure of the converging wedge becomes higher and  
Figure 7: Viscosity relationship of magnetic fluid lubrication film under magnetic field. the pressure of the diverging wedge becomes lower, the pressure difference between high and low pressure gradually increases, and the distribution range of high and low pressure gradually concentrates towards the minimum oil film thickness area, the highest pressure of the converging wedge reaches 8 MPa when the eccentricity is 0.8, and the lowest pressure of the diverging wedge is 2 MPa. This is because as the eccentricity increases, the size of the converging wedge inlet of the magnetic fluid lubricant film increases and the size of the outlet decreases, accumulating more and more magnetic fluid near the outlet of the converging wedge and increasing pressure; the size of the diverging wedge inlet decreases and the size of the outlet increases, with less and less magnetic fluid near the diverging wedge inlet and decreasing pressure. Thus, the magnetic fluid lubricating oil film has a strong wedge effect, and the oil film carrying capacity is increased, leaving the journal in a relatively balanced position [31]. Figure 8: Mesh convergence analysis experimental results. Figure 9: Magnetic fluid lubrication film pressure distribution. Figure 10 gives the oil film temperature distribution of magnetic fluid bearings with different eccentricity. As can be seen from the figure, the high temperature zone is mainly distributed in the middle of the oil film axis and around the minimum oil film thickness.