Nonlinear transient analysis of hole-entry journal bearing with constant flow of micropolar fluids

Budheeja, Kamal; Verma, Suresh

doi:10.1177/0954406218756942

Cited by 7 publications

(4 citation statements)

References 43 publications

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“…Additionally, some scholars apply the Reynolds equation to examine bearing lubrication characteristics [5][6][7][8]. Typically, bearing dynamics research initially focuses on determining the pressure of the bearing oil film, often investigated through solving the Navier-Stokes equation using CFD software [9][10][11][12]. Zi et al [13] performed steady-state calculations on plain and step bearings using CFD software, addressing the inertia terms and viscosity changes traditionally neglected in the Reynolds equation.…”

Section: Introductionmentioning

confidence: 99%

Impact of Oil Film Dynamics on the Performance of Aeroengine Plain Bearings

Liu,

Wang

2024

PMDF

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This investigation addresses the issue of premature failure or damage to bearing components in aeroengines, which often results from the release of dissolved gases in the lubricant due to environmental pressure changes during operation. Employing the three-dimensional Reynolds equation and focusing on an ideal lubricating oil, a lubrication model for the engine camshaft's oil film was developed. The formation and extent of gaseous voids within plain bearings were analyzed. The study systematically explored how fit clearance and lubricating oil viscosity influence oil film pressure and thickness. It was found that a reduced fit gap increases the oil film pressure gradient while decreasing the film's thickness. Additionally, although variations in lubricating oil viscosity do not affect the distribution of oil film thickness, they significantly impact the pressure exerted on the oil film, with higher viscosities leading to increased pressures. These findings provide essential theoretical guidance for the safety assessment of aeroengine plain bearings.

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Section: Introductionmentioning

confidence: 99%

Impact of Oil Film Dynamics on the Performance of Aeroengine Plain Bearings

Liu,

Wang

2024

PMDF

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“…Also, their results confirmed that the rotor perturbation in two-lobe bearings space was more affected by the variation of preload or noncircularity factor. Recently, Budheeja and Verma 23 analyzed the effects of creating a compensator including a constant flow restrictor valve on the transient response of a hole-entry hybrid bearing. Their results show that enhancing the micropolarity of lubricant can enhance the stability margin of investigated bearings.…”

Section: Introductionmentioning

confidence: 99%

Linear and nonlinear analysis of mount angle effects on the dynamic stability of micropolar lubricated hydrodynamic lobed journal bearings

Mehrjardi¹,

Rahmatabadi

Meybodi

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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Journal bearings are one of the most widely used types of supporting devices for industrial machinery, especially for high-speed rotary systems. Considering the importance of mechanical systems ability to control vibrations and motion disturbances, the design of noncircular journal bearings has been one of the appropriate techniques used in recent years. In the present work, the effects of mount angle as a noncircularity unique feature on the dynamic stability of lobed journal bearings with micropolar lubricant are studied. For this purpose, modified Reynolds equation based on the linear and nonlinear methods is solved by generalized differential quadrature (GDQ) method. Then the static and dynamic characteristics of two-, three- and four-lobe bearings including load carrying capacity, whirl frequency ratio, critical mass parameter and rotor perturbation in terms of bifurcation diagram and Poincare map are presented for different values of mount angle. Nonlinear analysis results indicate that variation of mount angle can change the rotor response from limit cycle oscillations to convergent perturbation to static equilibrium point. Further, against plain circular journal bearings, choosing an appropriate orientation or mounting angle provides the optimal stability of noncircular lobed journal bearings. Also, the linear analysis results for the range of dynamic stability are more cautious than the nonlinear method in most of investigated cases.

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“…They concluded that it was inappropriate to consider lubricants as isoviscous, and the performance of bearing was considerably affected by the rise in temperature. Budheeja and Verma 36 studied the hybrid journal bearing compensated with constant flow valve restrictor lubricated with micropolar lubricants and analyzed the influence of micropolarity of the lubricant on the journal bearing stability by utilizing the nonlinear transient model. They have indicated that for higher loads, micropolar lubricants helps for the considerable increase in the stability margin and also lubricant flow and type of lubricant must be selected appropriately for the journal bearing stability.…”

Section: Introductionmentioning

confidence: 99%

Steady-state performance of elliptical contact lubricated with micropolar fluids

Dewangan

Sarangi

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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In this work, the numerical investigation is done for the steady-state performance of elliptical contacts lubricated with micropolar fluids. The Eringen’s micro-continuum theory is applied to deduce the modified Reynolds equation for micropolar fluids. The modified Reynolds equation is discretized by the finite difference technique and evaluated by a multigrid technique for finding the steady-state pressure distribution; simultaneously, the elasticity equation is solved with the multilevel multi-integration method. The numerical solution is achieved under isothermal conditions and considering the exponential variation of viscosity with pressure. The effect of micropolar parameters, i.e. nondimensional characteristics length defines the molecular length of the blended additives, and coupling number measures the coupling between the angular and linear momentum of molecules, and operating parameters are studied. Owing to the analysis, the pronounced effect of the micropolar parameters on the elastohydrodynamic lubrication of elliptical contacts is observed and which cannot be avoided. Lubricants added with solid additives and coupling between linear and angular momentum improved the overall film thickness and pressure and enhanced the load-carrying capacity. Also, a nominal rise in the traction coefficient is noticed, but this increase in the traction coefficient is quite less when compared to Newtonian fluids.

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Nonlinear transient analysis of hole-entry journal bearing with constant flow of micropolar fluids

Cited by 7 publications

References 43 publications

Impact of Oil Film Dynamics on the Performance of Aeroengine Plain Bearings

Impact of Oil Film Dynamics on the Performance of Aeroengine Plain Bearings

Linear and nonlinear analysis of mount angle effects on the dynamic stability of micropolar lubricated hydrodynamic lobed journal bearings

Steady-state performance of elliptical contact lubricated with micropolar fluids

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