The roller-floating bush pin is a major component in the fuel supply mechanism of a diesel engine, and its tribological performance seriously affects the reliability of the equipment. In this study, a transient thermoelastic hydrodynamic lubrication analysis model of the double-layer oil film on the roller-floating bush pin is established, which is coupled with the dynamic and kinematic analysis model of the cam-roller. The transient dynamic characteristics, such as time-varying speeds and loads of the roller during the operation of the cam, were considered. Also, the elastic deformation and the thermal effect were considered in the lubrication model. The relevant experimental platform for this double-layer oil film lubrication structure was built, and the simulation model was verified through experiments. The influence of the operating conditions, including cam speed and plunger fuel pressure, on the lubrication performance of the structure is explored, and besides, the influence of the structural parameters, including length-diameter ratios and clearance ratios, is also analyzed. It shows the lubrication condition of the inner oil film is worse compared with the outer oil film. As the explored factors change, the pressure of the inner oil film is more affected than that of the outer oil film. This work could provide useful guidance in designing the roller-floating bush pin in the fuel supply mechanism.

This work studied the time-varying dynamic coefficients of journal–thrust coupled (JTC) bearing within a diesel engine crankshaft system. A transient thermoelastohydrodynamic coupled lubrication model of JTC bearings was established by considering pressure, flow, and heat continuity conditions at journal–thrust interface. On this basis, the dynamic coefficients of three degrees of freedom were further calculated. A transient lubrication experiment was conducted on a test rig to validate the established model. Parametric analysis was conducted to explore the transient lubrication performance and the dynamic coefficient of JTC bearing under different input parameters. Moreover, for cases when the crankshaft undergoes large axial movement, the influence of the JTC bearing dynamic coefficients on the natural characteristics of crankshaft were further analyzed to provide an analysis method for crankshaft vibration characteristics.

The flow behavior of the SnSbCu alloy is studied experimentally by the compression tests in the range of the strain rates from 0.0001 to 0.1 s⁻¹ and temperature from 293 to 413 K. Based on the experimental data, three constitutive models including the Johnson–Cook (J–C), modified Zerilli–Armstrong (Z–A), and Arrhenius-type (A-type) models are compared to find out an optimum model to describe the flow behavior of the SnSbCu alloy. The results show that the J–C model could predict the flow behavior of the SnSbCu alloy accurately only at some specific strain rates and temperature near the reference values. The modified Z–A and A-type constitutive models can give better fitting results than the J–C model. While, at high strains, the predictive values of the modified Z–A model have larger errors than those at low strains, which means this model has limitations at high strains. By comparison, the A-type model could predict the experimental results accurately at the whole strain range, which indicates that it is a more suitable choice to describe the flow behavior of the SnSbCu alloy in the focused range of strain rates and temperatures. The work is beneficial to solve the tribological problem of the bearing of the marine engine by integrating the accurate constitutive model into the corresponding numerical model.

Investigations on the influence of different cavity structures on the reliability and cooling of thrust bearings were performed. Four cavity structure models were built. The variation laws of reliability and cooling characteristics of thrust bearing fluid domain under different structure and operating condition parameters were discussed. The influence mechanism was revealed. Four cavity structures were optimized for parameters. The results show that the high-pressure regions of the step and taper cavity structures are slender. Thrust bearings with step or taper cavity structure have better reliability and cooling. Thrust bearings with step-pocket or taper-pocket cavity structure can provide greater stiffness and damping, which effectively suppress the axial vibration of the rotor system. The depth of the cavity has the greatest effect on the load-bearing capacity of thrust bearings with different cavity structures. Through parameter optimization, the load-carrying capacities of four thrust bearings are increased by 19.23%, 37.44%, 30.60%, and 73.28%, respectively. The aforementioned investigations can offer theoretical guidance for the design and optimization of thrust bearings.

The tilting-pad journal bearing in the cooling system of the nuclear power plant is equipped below the ground and vertically positioned to accomplish its function for water transfer. Usually, the loading conditions are relatively stable since the required water volume almost remains the same level during the operation, but the loading direction cannot be known in advance. Furthermore, the bearing is designed with several separate pads, which allows the bearing to support the loading flexibly. The safety application of nuclear energy requires the bearing to have a reliable ability to maintain the rotating motion of gear sets. This study develops a numerical model to simulate the mixed thermo-elastohydrodynamic lubrication for the tilting-pad journal bearing in the nuclear plant. The elastic and thermal fields are properly determined, and the induced displacement is taken into account for an accurate description of film thickness. The asperity contact due to misaligned journal is well evaluated in the local area where the lubrication film cannot separate the surfaces. A parametric study is undertaken in detail to reveal the aspects that influence bearing lubrication. The conclusions potentially provide fundamentals for further lubrication optimization of the bearing system.