Bin Wang

On maritime vessels, external factors such as explosions, collisions, and grounding can cause the emulsification of lubricating oil by seawater pollution, which can affect the lubrication of a ship’s thrust bearing. To explore the influence of the mixed emulsification of lubricating oil and seawater on the lubrication performance of thrust bearings, this study conducted an emulsification experiment, from which the viscosity equation of the oil–water mixture was obtained. A thermal hydrodynamic model (THD) of bearings considering oil–water mixed emulsification was established, and the Finite Difference Method (FDM) was used for analysis. The results show that according to the characteristics of the manifold, the mixture is divided into water-in-oil (W/O) and oil-in-water (O/W). In the W/O flow with higher viscosity, the film thickness becomes higher, but the power loss increases. In the O/W manifold with low viscosity, the thin film easily causes mixed friction. In the demulsification stage of the mixed liquid, the thickness loss of the film is huge, and the collision between the thrust-bearing pad and the inference plate may cause the pad to be ablated. The influence of specific heat capacity on temperature is greater than the temperature rise caused by viscosity.

Aiming at the problem that the traditional water-lubricated bearing cannot carry the heavy load and adapt to the constantly changing operating conditions for the high-power Rim Driven Thruster (RDT), the principle structure of the Magnetic Water-double-suspension Elastic-support Thrust Bearing (MWETB) is designed and the optimal structure parameters of the bearing are selected using simulation. To demonstrate the reliability of the MWETB under the RDTs’ actual working conditions, performance tests, which include the magnetic flux density, magnetic force, and lubrication performance, are carried out. The simulation and experimental results indicate that the optimal offset ratios are in two intervals, and the magnetic alignment and sheath materials have a great effect on the load reduction. The load-carrying force has obvious zoning characteristics with the change in bearing clearance. Besides, compared with the water-lubricated thrust bearings, the MWETB has advantages in terms of minimum film thickness and friction coefficient.

The water-lubricated tilting pad thrust bearings (WTTBs) of the reactor coolant main pump and high-power RDT operate at a large linear velocity, heavy load, and low viscosity. On the basis of the performance prediction of WTTBs in the mixing flow pattern, a hypothesis of the regional flow pattern is proposed. To compare the lubrication performance under four kinds of flow pattern modes, a thermo-elasto-hydrodynamic lubrication model of the WTTB considering the flow pattern is established, and a partition iteration algorithm for the mixing flow pattern is provided. Moreover, a method for controlling the flow pattern by changing the pad surface morphology is proposed. A simulation is used to indicate that the bearing performance under the mixing flow pattern calculated by the regional flow pattern mode is between that of the laminar and turbulent flows. The regional mixing flow pattern mode can automatically retrogress to the single flow pattern mode by changing the operation conditions. Both the circumferential bulge and radial concave pad surfaces are beneficial for increasing the turbulent area and thereby improving the load-carrying capacity of the WTTB.