Stability analysis of a rigid rotor supported by two-lobe hydrodynamic journal bearings operating with a non-Newtonian lubricant

Yadav, Saurabh; Rajput, Arvind K.; Ram, Nathi; Sharma, Satish C.

doi:10.1177/1350650118806377

Cited by 5 publications

(3 citation statements)

References 32 publications

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“…Song et al [21] studied the influence of shaft and bearing shape errors on the stability of journal bearings. Yadav et al [22] investigated the stability of the journal bearing using the 4th-order Runge-Kutta method in order to analyze the dynamic stability of the system. Dyk et al [23] used an analytical method to calculate the bearing dynamic coefficients but with a limited π-film condition.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

et al. 2023

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Misalignment is one of the most common challenges that the normal operation of journal bearings faces. This type of problem may be the result of a wide range of reasons, such as bearing wear, shaft deformation, and errors related to the manufacturing and installation process. The main undesirable consequences of the misalignment, such as pressure rise and lubricant film reduction, are concentrated on the bearing edges. Therefore, chamfering the bearing edges reduces such misalignment-related drawbacks. This work presents a novel numerical solution to the problem of finite-length journal bearing considering edge chamfering. This solution involves the determination of the levels of lubricant layer thickness and pressure distribution in addition to the journal trajectory under impact load with the related stability limits. The finite difference method is used in this solution, and the equations of motion are also solved numerically using the Runge–Kutta method. The Results of this novel analysis show that chamfering the bearing edges increases the film thickness and reduces pressure spikes associated with the system operation under the case of 3D misalignment. Furthermore, the chamfered bearing shows a wide stability range under impact loads, where the normal bearing is unstable as the critical speed increases by 26.98%, which has positive consequences on the journal’s trajectory.

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Section: Introductionmentioning

confidence: 99%

Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

et al. 2023

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“…Mehrjardi et al [28] used the fourth-order Runge-Kutta method in analyzing the stability of journal bearing, and their result showed that bearing noncircularity can improve the stability of the system. Yadav et al [29] also used the fourth-order Runge-Kutta method in investigating the stability of the journal bearing. An analytic solution to calculate the dynamic coefficients of the bearing was proposed by Dyk et al [30], but it was based on the limited π-film boundary condition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Chamfer Form and Parameters on the Characteristics of Finite Length Journal Bearing under Impact Load

et al. 2023

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Journal bearings in typical applications are subjected to misalignment due to several causes, such as shaft deformation under load and errors related to the installation and manufacturing processes. Misalignment has well-known severe negative consequences on the performance of the bearings. This paper deals with the bearing chamfer to reduce these consequences of misalignment, and two forms of bearing edge modification are considered in the analysis. These forms are linear and curved chamfering of the bearing edges, where the height of the chamfer in the circumferential direction and the length of the modification in the longitudinal direction are considered as geometrical design parameters. The investigation includes a numerical solution of the hydrodynamic lubrication problem of finite length journal bearing, considering 3D misalignment cases using the finite difference method. This includes the assessment of the chamfer forms and their effects on the bearing performance in terms of the main bearing design parameters. Furthermore, the stability of the chamfered bearings is also investigated under impact load. Results showed that both chamfer forms are beneficial for a certain limit of the design parameters in reducing the maximum pressure and coefficient of friction and in elevating the film thickness levels, extending the range of misalignment in which the journal bearing can operate safely. In addition, the chamfered bearings in both forms showed more stability range in terms of the critical speed and shaft center trajectories under impact load. The bearings with the curved chamfer, where the slope is continuous at the start of modification, showed more uniform film thickness levels, and their shaft center trajectories were closer to the perfectly aligned bearing in the stable operating range of the system.

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“…Using a similar strategy, Huang et al [9] studied the stability threshold by way of the dynamic coefficients with no coordinate transformation. Another commonly used approach is known as time series analysis, often also referred to as transient simulation [10][11][12]. As with the experimental method, in time series analysis, the stability threshold is generally estimated as the rotation speed at which the shaft leaves the steady equilibrium position.…”

Section: Introductionmentioning

confidence: 99%

Stability Analysis of Rotor-Bearing Systems under the Influence of Misalignment and Parameter Uncertainty

2021

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Stability is a well-known challenge for rotating systems supported by hydrodynamic bearings (HDBs), particularly for the condition where the misalignment effect and the parametric uncertainty are considered. This study investigates the impact of misalignment and inherent uncertainties in bearings on the stability of a rotor-bearing system. The misalignment effect is approximately described by introducing two misaligned angles. The characteristics of an HDB, such as pressure distribution and dynamic coefficients, are calculated by the finite difference method (FDM). The stability threshold is evaluated as the intersection of run-up curve and borderline. Viscosity and clearance are considered as uncertain parameters. The generalized polynomial chaos (gPC) expansion is adopted to quantify the uncertainty in parameters by evaluating unknown coefficients. The unknown gPC coefficients are obtained by using the collocation method. The results obtained by the gPC expansion are compared with those of the Monte Carlo (MC) simulation. The results show that the characteristics of the HDB and the stability threshold are affected by misalignment and parameter uncertainties. As the uncertainty analysis using the gPC expansion is performed on a relatively small number of predefined collocation points compared with the large number of MC samples, the method is very efficient in terms of computation time.

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Stability analysis of a rigid rotor supported by two-lobe hydrodynamic journal bearings operating with a non-Newtonian lubricant

Cited by 5 publications

References 32 publications

Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

Analysis of the Performance of Chamfered Finite-Length Journal Bearings under Dynamic Loads

Effect of Chamfer Form and Parameters on the Characteristics of Finite Length Journal Bearing under Impact Load

Stability Analysis of Rotor-Bearing Systems under the Influence of Misalignment and Parameter Uncertainty

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