Simulation-based fabrication of micro-helical grooves in a hydrodynamic thrust bearing by using ECMM

Int J Adv Manuf Technol

Hou

2016

Titanium alloys are widely used in the aerospace and biomedical industries. Micro-dimple arrays, as a kind of surface texture, have been applied on titanium alloy surfaces to enhance tribological behaviour as well as to affect the biological performance of titanium implants. Through-mask electrochemical micromachining (TMEMM) is a promising approach to generate micro-dimple arrays on metal surfaces. In general, sodium bromide and methanol-sulfuric acid, which could dissolve the passive oxide layer on titanium alloy surfaces, are used as electrolytes to generate micro-dimple arrays. However, these electrolytes are caustic, which can damage the equipment, and are unfavourable for industrial applications. In this paper, an environmentally friendly NaNO 3 electrolyte was employed to generate micro-dimple arrays on titanium alloy surfaces in TMEMM with a reusable mask; this made the process more efficient and safer. Experiments showed that there was serious stray corrosion on the titanium alloy surfaces when the micro-dimple arrays were generated using direct current. To obtain high-quality micro-dimple arrays, a pulsed current was employed in TMEMM. The results showed that machining parameters of applied voltage of 24 V, pulse duty cycle of 10 % and frequency of 100 Hz were appropriate to improve the machining quality. Micro-dimple arrays with no stray corrosion were thus generated. Moreover, the electrolyte temperature also influenced the machining accuracy, and a low electrolyte temperature of 20°C was useful to reduce the undercutting of micro-dimples and improve machining localization. With the optimized parameters, micro-dimples with a diameter of 110 μm and depth of 20 μm were generated.

Section: Investigating the Generation Of Micro-dimple Arrays With Pulmentioning

confidence: 94%

Electrochemical micromachining of micro-dimple arrays on the surface of Ti-6Al-4V with NaNO3 electrolyte

Int J Adv Manuf Technol

Hou

2016

“…In general, the oil-film is assumed to be filled with the clearance of SGTB [1][2]. However, the appearance of physical characteristics and structural parameter will cause the change of lubrication characteristics, such as viscosity, density and spiral shape.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of hydrodynamic lubrication phenomenon in thrust bearing with cavitation

Wang

et al. 2022

Preprint

A mixed computational model is presented to evaluate the hydrodynamic lubrication phenomenon of spiral grooved thrust bearing (SGTB). With cavitation effects taken into account, this model is developed with a high-level capability for describing the hydrodynamic lubrication phenomenon of SGTB. For design parameter and operation condition, the model includes the influence of lubricated medium, shear rate and lubricant layer, which could ensure the computational accuracy. Meanwhile, the correctness and effectiveness of simulation model are demonstrated by the published experiment data. In addition, the lubrication characteristics of SGTB reveal the correlation property between design parameters and hydrodynamic response.

“…The method and techniques of modeling are improved based on the development of faster data processing capabilities for computer. Then, it is necessary to establish the exact model of SGTB for studying the influence of groove parameters on the hydrodynamic behavior of SGTB with gas lubricant [5,6].…”

Section: Introductionmentioning

confidence: 99%

Study of Groove Parameters on the Hydrodynamic Behavior of Spiral-Grooved Thrust Bearing with Gas Lubricant

Xia

International Journal of Rotating Machinery

Wang

et al. 2021

The gas-lubricated thrust bearing is widely used in agriculture mechanical systems, and the groove shape plays an important role on the hydrodynamic behavior of spiral-grooved thrust bearing (SGTB). Although the groove shape may change smaller, it is clear that the hydrodynamic response is very sensitive to the groove parameters. This paper proposes a computational method for the analysis of SGTB with gas lubricant, considering the effects of groove parameters. With the compressibility taken into account, the evaluation of lubrication performance for SGTB is obtained by the CFD technology. Also, the simulation results are compared with the published data, which indicates that the presented model of SGTB is able to obtain more realistic results of hydrodynamic characteristics of SGTB. Moreover, the mapping relationship between groove parameter and hydrodynamic behavior of SGTB is represented.