Investigation of Cavitation in a Finite Journal Bearing Considering the Journal Speed and Couple Stress Fluids Effects

Mahdi, Mushrek A.; Hussain, A.; Hadwan, H.H.

doi:10.24874/ti.2018.40.04.13

Cited by 4 publications

(7 citation statements)

References 15 publications

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“…Solghar [10] reported higher load carrying capacity and friction coefficient of journal bearings using Al2O3 based nanolubricants. Mahdi et al [11] used the couple stress fluid model for studying cavitation effects in bearing. Sadabadi and Nezhad [12] simulated the journal bearing used in heavy machinery which is lubricated with Tungsten disulfide (WS2) based nanolubricants and reported a maximum of 20% rise in load carrying capacity.…”

Section: Researchmentioning

confidence: 99%

Numerical Investigation of Short Bearing Lubricated with Copper Oxide Nanolubricants

G. Chavan,

Reddy

2024

Tribol. Ind.

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Performance of short hydrodynamic journal bearing lubricated with Copper oxide (CuO) nanoparticle suspensions in base oil (nanolubricants) is investigated numerically. Dimensionless pressure, load carrying capacity and friction parameter are calculated by numerical solution of the modified Reynolds equation by means of finite difference method. The particular values of couple stress parameter for nanolubricants are evaluated and used for finding pressure distribution. Modified Krieger Dougherty equation is used to predict the viscosity of nanolubricant. Two short bearing configurations with aspect ratio 0.25 and 0.5 are analyzed by evaluating the pressure profile, load carrying capacity and friction parameter. The comparative results between plain lubricants and nanolubricants are presented. The results reveal improved pressure and load carrying capacity accompanied by decrease in friction parameter of short bearing. The shorter bearing configuration with aspect ratio of 0.25 shows better results than the others.

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Section: Researchmentioning

confidence: 99%

Numerical Investigation of Short Bearing Lubricated with Copper Oxide Nanolubricants

G. Chavan,

Reddy

2024

Tribol. Ind.

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“…Main advantages of the base oils of high viscosity index are highly reliable components of machine parts within a wide range of working temperature, a longer life, and a good response to additives. [16][17][18] The non-dimensional form of the equation (1) can be written as…”

Section: Modified Reynolds Equationmentioning

confidence: 99%

“…The results demonstrated that when couple stress fluid is used instead of a Newtonian lubricant, the stiffness and damping coefficients of journal bearings can be increased. The effects of journal speed and the characteristic parameters of couple stress lubricants on the cavitation zone in a finite journal bearing are investigated by Mahdi et al 17 They used the Elrod cavitation algorithm to solve the modified Reynolds equation. It is concluded that applying the couple stress lubricants enhances the fill-film pressure and load carrying capacity, reduces the Sommerfeld number, and leads to a small drop in the values of the bearing side leakage flow.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic stability analysis of noncircular two-lobe journal bearings with couple stress lubricant regime

Mehrjardi¹

2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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In this research, the steady state and dynamic performances of two-lobe noncircular journal bearings with couple stress lubricant are presented. The lubricating oil, containing additives and contaminants, is modeled as the couple stress fluid. The modified Reynolds equation is obtained using the couple stress lubrication theory and is then solved by finite element method as an efficient numerical technique. The steady-state characteristics of bearings, including the load carrying capacity and attitude angle, are determined for various values of the couple stress parameter. The results show that applying the couple stress fluid improves the efficiency of two-lobe bearings in terms of an increased load carrying capacity and reduced attitude angle. Also, the stability performance of the investigated bearings is studied using rotor motion equations based on linear and nonlinear dynamic methods. The results indicate that any increase in the lubricant couple stress parameter enhances the bearing ability to damp the rotor perturbations. In other words, by varying the lubricant from Newtonian oil to the couple stress type and upgrading its properties, the curves of the critical mass parameter and whirl frequency ratio have an increasing and decreasing trend, respectively. Based on the fourth-order Runge–Kutta method results, the dynamic trajectory of the rotor center in the bearing space changes with increasing the couple stress parameter from diverging disturbances and limits the cycle perturbations around the bearing center to converging oscillations to the static equilibrium point. Moreover, the effect of changing lubricant properties on the two-lobe bearing’s performance is more pronounced at higher values of the couple stress parameter, especially with an increase in the noncircularity of bearings’ geometry.

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“…Sharma et al (2016) investigated the effects of surface condition on couple stress fluids for a finite journal bearing with Jakobsson–Floberg–Olsson boundary conditions (Jakobson and Floberg, 1957; Olsson, 1965) and found an increase in load carrying capacity at different eccentricity ratios. Mahdi et al (2018) investigated the combined effect of journal speed and couple stress fluids on the performance of a cavitated finite journal bearing. They used the Elrod's algorithm (Elrod, 1981) in the solution of the modified Reynolds equation.…”

Section: Introductionmentioning

confidence: 99%

Effects of both cavitation and non-Newtonian behavior on the performance of oscillatory anisotropic poroelastic squeeze film

Sobhi¹,

Khlifi²,

Nabhani³

2022

ILT

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Purpose The purpose of this study is to present a theoretical investigation of the effects of cavitation and couple stress on the squeeze film behavior between an anisotropic poroelastic rigid disc and a sinusoidally oscillating rigid disc. Design/methodology/approach Based on the microcontinuum theory of Vijay Kumar Stokes and the Elrod–Adam algorithm, the non-Newtonian Reynolds equation coupled with modified Darcy's law for lubricant flow through the porous disc is derived. This numerical study includes the continuity of tangential velocity at the porous–fluid interface and the effects of percolation of the polar additives into the anisotropic porous disc. Findings The effects of couple stress, oscillating amplitude, percolation additives, permeability and anisotropic permeability on the squeeze film characteristics are discussed. It is found that both the percolation effect of the lubricant additives and the anisotropic structure of the porous surface reduce the flow in the porous disc, resulting in a decrease in pressure. It is also observed that cavitation effects are more pronounced for Newtonian fluids than couple stress fluids. Originality/value The results of this study can be used to design a variety of engineering applications such as bearings, wet clutches and non-contact mechanical seals.

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Investigation of Cavitation in a Finite Journal Bearing Considering the Journal Speed and Couple Stress Fluids Effects

Cited by 4 publications

References 15 publications

Numerical Investigation of Short Bearing Lubricated with Copper Oxide Nanolubricants

Numerical Investigation of Short Bearing Lubricated with Copper Oxide Nanolubricants

Dynamic stability analysis of noncircular two-lobe journal bearings with couple stress lubricant regime

Effects of both cavitation and non-Newtonian behavior on the performance of oscillatory anisotropic poroelastic squeeze film

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