## 3 Research Results and Discussion  
### Simulation and Experimental Results  
Figure 9 shows that water flows radially and circumferentially from the groove, thereby indicating that circumferential and radial velocity gradients exist in the HTB clearance. Figure 10 shows simulation results of the water film pressure distribution on the static ring surface of the star wheel shaft's HTB under different axial forces of the star wheel and water injection pressures. Evidently, when the water injection pressure is constant, water film thickness between the static and rotating bearing rings decreases gradually with an increase in their loads. When the water film reaches at least 0.1 mm, pressure on the entire surface of the HTB ring is nearly the same. For different star wheel HTBs, a varying range of water film thickness is often expected to be between 0.03 mm and 0.05 mm to maintain reasonable clearances between star wheel pieces and compressor cylinder [24]. However, water film thickness should not be markedly below 0.015 mm to avoid direct contact between the two solid surfaces of a bearing. In this manner, for the numerous HTBs used in WSSCs, the excellent working stability of the star wheel in the axle is expected when the minimum and maximum values of water films are 0.015 mm and 0.06 mm, respectively. Figure 9: Water velocity distribution on the sliding surface of a star wheel shaft HTB. Figure 11 depicts a sectional view of 3D pressure distribution of the water-lubricated HTB of a star wheel shaft in a WSSC on a sliding surface. Figure 11: 3D pressure distribution in the lubrication film of the HTB. Figure 10: Pressure distribution of hydrostatic water film on static ring surface of star wheel shaft HTB: (**a**) \(p=0.5\) MPa, F\({}_{\text{gmax}}\), h = 0.02 mm; (**b**) \(p=1.2\) MPa, F\({}_{\text{gmax}}\), h = 0.04 mm; (**c**) \(p=0.5\) MPa, \(1/3\) F\({}_{\text{gmax}}\), h = 0.07 mm; (**d**) \(p=1.2\) MPa, \(1/3\) F\({}_{\text{gmax}}\), h = 0.10 mm. Figure 11 shows the intuitive trend of pressure distribution that pressure in the water groove is the highest and gradually decreases in the radial direction of the inner and outer edge of the bearing. Under the dynamic periodic load simulating the real force of the star wheel, Figure 12 shows the change of the liquid film thickness of the bearing. The displacement in the figure is the water film thickness in the bearing clearance. It is seen that although the exerted electromagnet force fluctuates substantially, the measured water lubricating the film in the bearing sliding clearance is nearly constant. The high frequency of the exerted load can also obtain steady water-lubricating film thickness. To verify the performance of the hydrostatic thrust bearing designed in this paper, some comparisons are made as follows. Figure 13 shows the comparison of the bearing capacity. On the basis of the same hydrostatic chamber area, the lubrication characteristics of the hydrostatic bearing with the traditional annular groove are compared with those of the hydrostatic bearing with the groove described in this research under the same depth of hydrostatic chamber. For cases with three water injection pressures, Figure 13a shows a comparison of the variation of bearing capacity with the water film thickness of HTBs with the traditional annular groove and a crossing groove. Figure 13b represents a comparison of the experimental results with simulated results of the relationship between the bearing capacity of the HTB of the star wheel shaft and the water film thickness under three different water injection pressures. The calculation method for the bearing capacity of an HTB with an annular groove in this paper is the same as that in the literature [13; 28]; the calculated results in this paper are basically consistent with their trend and value ratio. Evidently, the bearing capacity of HTB with an annular groove is larger than that of the crossing groove. The difference increases with an increase in the water injection pressure.