“…Additionally, the simulation parameters, including the geometry and the operating condition, adopted in the following sections are listed in Table 2. Figure 6.Verification of the hydrodynamic performance: (a) straight-grooved journal bearing; 23 (b) angularly microgroove thrust bearing, 13 and (c) coupled journal-thrust bearing. 8 …”
Section: Resultsmentioning
confidence: 99%
“…More recently, Gong et al. 23 carried out a numerical study to identify the influencing factors on the hydrodynamic performance of partial-grooved water-lubricated bearing. The authors found that there is an optimal microgroove depth when the eccentricity ratio bearing is relatively small.…”
Section: Introductionmentioning
confidence: 99%
“…It is noteworthy that the numerical models presented by Gong et al. 23 and Xiang et al. 24 fail to address the common boundary condition related to the hydrodynamic pressure and the fluid field, as shown in Figure 1.…”
The novelty of this study is to develop a hydrodynamic lubrication numerical model for coupled microgroove journal-thrust bearings (or coupled bearings) under water-lubricated condition. In the present model, the continuity of the hydrodynamic pressure and the fluid field (or coupled hydrodynamic effect) at common boundary is considered to reveal the mutual effect between the hydrodynamic behavior of the journal bearing and the thrust bearing. The lubrication performances of the coupled microgroove bearing with three bottom shapes, i.e., isosceles triangle, right triangle, and left triangle, are studied comparatively. Additionally, the effects of the microgroove depth on the lubrication performances of the coupled bearing are discussed. The present study reveals that the coupled hydrodynamic effect generated by the coupled bearing can improve the lubrication performance for both the journal and the thrust bearing. The microgroove with left triangle bottom shape yields the optimal lubrication performance as compared to the other two. There is an optimal groove depth that generates the maximum load capacity and the minimum friction coefficient for both the journal and the thrust bearing.
“…Additionally, the simulation parameters, including the geometry and the operating condition, adopted in the following sections are listed in Table 2. Figure 6.Verification of the hydrodynamic performance: (a) straight-grooved journal bearing; 23 (b) angularly microgroove thrust bearing, 13 and (c) coupled journal-thrust bearing. 8 …”
Section: Resultsmentioning
confidence: 99%
“…More recently, Gong et al. 23 carried out a numerical study to identify the influencing factors on the hydrodynamic performance of partial-grooved water-lubricated bearing. The authors found that there is an optimal microgroove depth when the eccentricity ratio bearing is relatively small.…”
Section: Introductionmentioning
confidence: 99%
“…It is noteworthy that the numerical models presented by Gong et al. 23 and Xiang et al. 24 fail to address the common boundary condition related to the hydrodynamic pressure and the fluid field, as shown in Figure 1.…”
The novelty of this study is to develop a hydrodynamic lubrication numerical model for coupled microgroove journal-thrust bearings (or coupled bearings) under water-lubricated condition. In the present model, the continuity of the hydrodynamic pressure and the fluid field (or coupled hydrodynamic effect) at common boundary is considered to reveal the mutual effect between the hydrodynamic behavior of the journal bearing and the thrust bearing. The lubrication performances of the coupled microgroove bearing with three bottom shapes, i.e., isosceles triangle, right triangle, and left triangle, are studied comparatively. Additionally, the effects of the microgroove depth on the lubrication performances of the coupled bearing are discussed. The present study reveals that the coupled hydrodynamic effect generated by the coupled bearing can improve the lubrication performance for both the journal and the thrust bearing. The microgroove with left triangle bottom shape yields the optimal lubrication performance as compared to the other two. There is an optimal groove depth that generates the maximum load capacity and the minimum friction coefficient for both the journal and the thrust bearing.
“…[1,2] Among these, reduction of friction and noise still remains one of the greatest challenges and the search for new materials, structure, and lubricants continues around the world. [3,4] Despite application of oil and grease was the most traditional method to control friction and noise, leakage of such materials will unambiguously precipitate and accumulate in the marine organism, which cause disruption of the structure and function of ecosystems. [5,6] Therefore, the quest for developing water-lubricated thrust bearings still continues due to its intrinsic adaptability in underwater working environment.…”
Minimization and suppression of friction and noise in underwater bearings remains a key aspect in modern marine vehicle industry owing to the growing need for reliability, and passenger comfort. In this study, graphene nano‐flake (Gr) was introduced into the nitrile butadiene rubber (NBR) with assistance of ionic liquid (IL). Owing to the positive charge generated by the secondary ordering layer on the Gr surface, Gr were effectively exfoliate into few layers and uniformly dispersed in the NBR matrix. Accordingly, the friction coefficient and volume wear rate decreased to 0.3124 and 6.44 × 10−6 mm3·N−1·m−1 in the nanocomposite, depicting a 31.52% and 51.9% reduction than pure NBR. It was demonstrated that the reinforced hardness and the formation of tribological layer of Gr played a vital role in the lubricating mechanism where both deformation and the continuation of the stick–slip effect were prevented. As a proof of concept, the total vibration acceleration level of the NBR/GR‐IL composite decreased from 111.37 ± 5.57 dB to 79.68 ± 3.98 dB, exhibiting good noise and vibration suppression effect. This work not only broadens the application of GR‐based materials, but also shed some light on the designing philosophy to improve the efficiency, service life and safety of the future marine vehicles.
“…In actual working condition, the surface of bearing bears high temperature and pressure, especially in the marine engine main bearing, which the authors focus on. According to the research [4,5,6,7], it can be known that the specific pressure of the main bearing caused by the oil pressure and asperity contact ranges from tens of MPa to several hundred MPa (usually less than 300 MPa), and the temperature of the bearing shell is maintained between 323 K and 423 K. For most existing research studies about the bearing tribological performance, the material properties are usually considered as the constants under the operating condition [8,9,10]. However, as some research studies indicated in another field [11,12,13], the material constants would change since the flow behavior is influenced by three factors: strain, strain rate, and temperature.…”
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.
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