Effects of axial profile on the main bearing performance of internal combustion engine and its optimization using multiobjective optimization algorithms

Ren, Peirong; Zuo, Zhengxing; Huang, Weiqing

doi:10.1007/s12206-021-0724-8

Cited by 7 publications

(5 citation statements)

References 36 publications

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“…By substituting Equations ( 10)- (20) into Equation ( 2), the pressure at point i, j can be given by:…”

Section: Numerical Solutionmentioning

confidence: 99%

“…Chasalevris and Dohnal in 2016 [19] used journal bearings of variable geometry to improve the stability of the system. More recently Ren et al in 2021 [20] studied numerically the effects of the axial profile parameters on the bearing's performance, where their results showed that using quadratic profile significantly improves the bearing's performance.…”

Section: Introductionmentioning

confidence: 99%

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Minimizing Misalignment Effects in Finite Length Journal Bearings

Jamali

Aljibori

Senatore

et al. 2022

Designs

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This paper focuses on a method to reduce the detrimental effects that occur due to the misalignment in journal bearings by approaching it with the more complete model of a finite length bearing. Such a drawback is quite common in industrial applications, and it is generally accepted that misalignment causes a significant thinning in the film thickness in the area that is close to the bearing edges. Therefore, removing a certain volume of material from the inner surface of the bearing (bushing) over a distance that is at the bearing edges provides an additional clearance to compensate for the clearance reduction that is due to misalignment. A numerical solution that is used in this work is based on the finite difference method where the Reynolds boundary conditions are considered in the solution scheme, thereby, using an iterative procedure to identify the cavitation zone. A three-dimensional misalignment model is incorporated in the solution in order to provide a more realistic presentation of the deviations and errors that there are in comparison with the ideal aligned case. It has been found in the present work that the edge modification increases the thickness of the lubricant layer considerably and reduces the pressure spikes that are associated with the presence of misalignment. The suggested design also reduces the coefficient of friction in comparison with that of the misaligned case. Furthermore, this method helps in reducing the asymmetry of the hydrodynamic pressure field that results from the misalignment. This method enables the operation of journal bearings over a wider range of misalignment levels without sacrificing the load-carrying capacity of the bearing by maintaining a relatively thicker layer of lubricant at the critical positions that are not so due to the effects of misalignment.

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“…By substituting Equations ( 10)- (20) into Equation ( 2), the pressure at point i, j can be given by:…”

Section: Numerical Solutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Minimizing Misalignment Effects in Finite Length Journal Bearings

Jamali

Aljibori

Senatore

et al. 2022

Designs

View full text Add to dashboard Cite

show abstract

“…Chasalevris and Dohnal [22] showed that the stability of the journal-bearing system can be improved based on the use of variable geometry. Recently, Ren et al [23] used a numerical investigation to study the effects of profile parameters on the bearing performance, where the results showed that the quadratic profile improves the bearing performance significantly. Jamali et al [24,25] showed that the bearing performance can be improved by using a variable bearing profile.…”

Section: Introductionmentioning

confidence: 99%

A New Geometrical Design to Overcome the Asymmetric Pressure Problem and the Resulting Response of Rotor-Bearing System to Unbalance Excitation

Jamali,

Aljibori,

Al-Tamimi

et al. 2023

Axioms

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Improving the bearing design helps in reducing the negative consequences related to errors in installation, manufacturing, deflections under severe loading conditions, progressive wear of machine elements, and many other aspects. One of the methods of such a design improvement effort is changing the bearing profile along the bearing width to compensate for the reduction in the geometrical gap between the shaft and the bearing inner surface due to the aforementioned causes. Since in all rotating machinery, unbalance usually exists at some level, this paper deals with the response of this modified bearing to unbalanced excitation to evaluate the effectiveness of such geometrical design on the dynamic characteristics of the rotor-bearing system. The numerical solution is performed using the finite difference method by assuming Reynolds boundary conditions to determine the cavitation limits, and the 4th-order Range-Kutta method is used to determine the time responses resulting from the unbalance excitation. The time responses to this type of excitation show that the rotor-bearing with the improved geometrical design is more stable, particularly at high speeds. In addition, this modification leads to an improvement in the lubricant layer thickness and the reduction in the levels of the generated pressure between the surfaces despite the presence of large deviations from the perfectly aligned bearing system. Furthermore, the suggested geometrical design overcomes the problem of asymmetricity in the pressure field resulting from the shaft deviation to a large extent. The results of this work (the enhancement in the level of the film thickness and the improvement in the dynamic response of the system as well as the reduction of the maximum pressure value) extend the range of misalignment in which the rotor bearing systems can operate safely which represents a significant step in designing the rotor-bearing system.

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“…Chasalevris and Dohnal [26] suggested using variable bearing geometry to improve the system's dynamic behavior. Ren et al [27] recently used a quadratic bearing profile in a numerical solution to improve bearing performance. Researchers have attempted to evaluate the impact of varying the bearing geometry on its performance, such as [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

A Novel Optimization Strategy of Bearing Geometry with a Length to Diameter Ratio of 1.25 under Severe Operating Conditions Using Taguchi Method

Jamali,

Mohammed,

Aljibori

et al. 2023

Designs

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Robust and well-designed rotor-bearing systems ensure safe operation and a high level of reliability under severe operating conditions. A deviation in the shaft axis with respect to the bearing longitudinal axis represents one of the most unavoidable problems in bearing systems. This deviation results from installation errors, manufacturing errors, shaft deformation under heavy loads, bearing wear, and many other causes. Each of these deviation sources has its negative consequences on the designed characteristics of the system. This work deals with the geometrical design of a journal bearing using three forms of profiles (linear (n=1), quadratic n=2 and cubic (n=3) profiles) in order to enhance bearing performance despite the presence of the inevitable shaft deviation. In addition, a wide range of bearing profile parameters are considered in the analysis to optimize the bearing profile based on the use of the Taguchi method. A general form of shaft deviation is considered to account for both horizontal and vertical deviations. A numerical solution is obtained using the finite difference method. The results show that all three suggested forms of bearing profiles elevate the film thickness significantly and also reduce the friction coefficient, but with different effects on the maximum pressure values. The Taguchi method illustrates that the optimal geometrical design parameters are the quadratic profile and the modification of one-fifth of the bearing width from both sides at a height of just less than half the radial clearance (0.4 C) at the bearing edges. These values give the best combination of the considered main bearing characteristics: the minimum film thickness, coefficient of friction, and maximum pressure. The results show that the minimum film thickness is increased by 184%, the maximum pressure is reduced by 15.1% and the friction coefficient is decreased by 6.4% due to the use of the suggested design. The outcome of this work represents an important enhancement step for the rotor bearing performance to work safely with high reliability under severe shaft deviation levels. This can be implied at the design stage of the bearing, which requires prior knowledge about the operating conditions in order to have better estimation for the levels of shaft deviation.

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Effects of axial profile on the main bearing performance of internal combustion engine and its optimization using multiobjective optimization algorithms

Cited by 7 publications

References 36 publications

Minimizing Misalignment Effects in Finite Length Journal Bearings

Minimizing Misalignment Effects in Finite Length Journal Bearings

A New Geometrical Design to Overcome the Asymmetric Pressure Problem and the Resulting Response of Rotor-Bearing System to Unbalance Excitation

A Novel Optimization Strategy of Bearing Geometry with a Length to Diameter Ratio of 1.25 under Severe Operating Conditions Using Taguchi Method

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