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This paper aims to prevent oil starvation and improve the service life of the rolling bearings.

A thrust ball bearing with magnetic circuit structure is proposed for ferrofluid lubrication. With the aid of magnetic field, ferrofluid can be maintained in the contact area of rolling bodies to delay lubricant loss. Experiments are performed to ensure the validity of the designed bearing.

Compared with conventional lubricant, service life of the ferrofluid lubricated bearing can be prolonged under magnetic field. In addition, with a proper magnetic field distribution, lubricant starvation may be limited under the conditions of present experiments.

This work provides a method to control the starved lubrication of rolling bearings with restricted lubricant supply.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0132/

The purpose of this paper is to artificially construct a functional surface with self-propulsion flow characteristics for the directional transportation of propellant in surface tension tanks.

In this study, a method to enhance the propulsion efficiency by using functional surfaces of self-propulsion performance was proposed. Superhydrophilic wedged-groove with the superhydrophobic background was fabricated and the self-propulsion capacity was verified.

It is found that the self-propulsion capacity is related to the divergence angle of the wedged-groove in the hydrophilic area, and the velocity of the droplets on the deflector plate is the largest with the divergence angle of 4°; the temperature gradient field formed by the condensing device at the nozzle can accelerate the droplet outflow from the tank.

Realization of this idea provides an accurate control strategy for the complex flow process of propellant in plate surface tension tanks, which could enhance the efficiency of the tension tank significantly.

This study aims to simultaneously enhance the load-carrying capacity and control the leakage rate of mechanical seals by optimizing the texture shape.

A multi-objective optimization approach is implemented to determine the optimal “free-form” textures and optimal circular dimples. Experiments are conducted to validate the simulation results.

The experimental coefficient of friction (COF) and leakage rate are in good agreement with the calculated results. In addition, the optimal “free-form” texture shows a lower COF and a lower leakage in most cases.

This work provides a method to optimize the surface texture for a better combination performance of mechanical seals.

This paper aims to investigate the influence of high-temperature thermal action on grease performance from the angle of film-forming performance.

A static thermal aging method was used to prepare high-temperature thermal grease samples after high-temperature thermal action. On the basis of optical interference technology, the film-forming characteristics of fresh grease samples and the grease samples after high-temperature thermal action under variable speed and fixed speed conditions were explored.

The decrease in the structural entanglement performance of the grease after short-term high-temperature thermal action makes its film-forming performance better. The mechanism is that the lubricating grease soap fiber entanglement is reduced. Although the continuous high-temperature thermal action can make the grease film-forming performance better, its mechanism is that the soap fiber structure caused by high-temperature thermal action is damaged and is easy to be cut off under the action of shear.

The effect of structural system change on its film formation performance was discussed in combination with the change in grease structure characteristics, and the mechanism of action was revealed.

This paper aims to study the lubrication and sealing performance on the textured piston pair under the cross action of the shape and structure parameters. This paper further carries out the optimization design of low energy consumption hydraulic impact piston pair.

Based on the characteristics of the ring gap seal piston pair, the flow field analysis model of the whole film gap is established for its periodic treatment. The friction power loss of the piston pair is defined as the evaluation index of the lubrication performance and the leakage power loss as the evaluation index of the sealing performance. The orthogonal test design and CFD software were used to analyze the lubrication and sealing performance of the textured piston pair.

The cross action of shape and structure factors has a great influence of the lubrication and sealing performance on the textured piston pair. Clearance and shape parameters have great influence on it, while seal length and depth diameter ratio have little influence. The sealing performance of conical textured piston pair is good, while the lubrication performance of square textured piston pair is good. The primary and secondary order of influence of shape and structure on energy consumption on piston pair is B (seal clearance) > C (texture shape) > D (area ratio) > A (seal length) > E (depth diameter ratio).

Breaking the defect of local optimization design on traditional piston pair structure, then find the matching relationship of structural parameters on textured piston pair. Further improve the lubrication and sealing performance of the piston pair, and provide reference for the global optimization design of the low energy consumption hydraulic impact piston pair.