Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Prölß, Maximilian; Schwarze, Hubert; Hagemann, Thomas; Zemella, Philipp; Winking, Philipp

doi:10.3390/lubricants6040105

Cited by 14 publications

(12 citation statements)

References 28 publications

(39 reference statements)

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“…An application of the theory of Greenwood and Williamson [24] provides a relation between the mean film thickness on the node of the numerical grid and solid contact pressure due to the interaction of the asperities that is shown in Figure 7b. The contact surface features a root mean square roughness value of Rq = 2.83 μm and matches the one earlier presented by the authors in [25]. A turning process generates the surface topography that features small grooves in the circumferential direction.…”

Section: Flow Factors and Solid Contact Pressuresupporting

confidence: 85%

Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part I: Basic Relations

et al. 2021

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The application of sliding planet gear bearings in wind turbine gearboxes has become more common in recent years. Assuming practically applied helix angles, the gear mesh of the planet stage causes high force and moment loads for these bearings involving high local loads at the bearing edges. Specific operating behavior and suitable design measures to cope with these challenging conditions are studied in detail based on a thermo-hydrodynamic (THD) bearing model. Radial clearance and axial crowning are identified as important design parameters to reduce maximum pressures occurring at the bearing edges. Furthermore, results indicate that a distinct analysis of the gear mesh load distribution is required to characterize bearing operating behavior at part-load. Here, operating conditions as critical as the ones reached at nominal load might occur. Wear phenomena can improve the shape of the gap in the circumferential as well as in axial direction incorporating a significant reduction of local maximum pressures. The complexity of the combination of these aspects and the additionally expected impact of structure deformation gives an insight into the challenges in the design processes of sliding planet gear bearings for wind turbine gearbox applications.

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Section: Flow Factors and Solid Contact Pressuresupporting

confidence: 85%

Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part I: Basic Relations

et al. 2021

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“…From Figures 13 and 16, it is also observed that the whirl ratio and mass parameters are insensitive to uncertainty in oil viscosity and supply pressure for some specific operating conditions (ε = 0.6-0.7 for the whirl ratio and ε = 0.4-0.6 for the mass parameter) indicating robust operating conditions. Figures 6,9,12,15,and 18 show the effect of oil viscosity and supply pressure on the hydrodynamic performance of a two-axial-groove journal bearing for various degrees of stochasticity. From where it can be observed that the effect of stochasticity in oil viscosity and supply pressure increases as the degree of stochasticity increases.…”

Section: Resultsmentioning

confidence: 99%

“…The existing design methodology of a journal bearing is completely based on the theoretical results obtained from the deterministic analysis without considering the geometrical and operational uncertainties. As a result, a significant difference 12 between the experimental and theoretical results is observed. In this context, the inclusion of uncertainties in geometric parameters or operating conditions in the design process of journal bearings is an important design issue.…”

Section: Introductionmentioning

confidence: 92%

Machine learning-based performance analysis of two-axial-groove hydrodynamic journal bearings

Roy

Dey

2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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The precise prediction of a rotor against instability is needed for avoiding the degradation or failure of the system’s performance due to the parametric variabilities of a bearing system. In general, the design of the journal bearing is framed based on the deterministic theoretical analysis. To map the precise prediction of hydrodynamic performance, it is needed to include the uncertain effect of input parameters on the output behavior of the journal bearing. This paper presents the uncertain hydrodynamic analysis of a two-axial-groove journal bearing including randomness in bearing oil viscosity and supply pressure. To simulate the uncertainty in the input parameters, the Monte Carlo simulation is carried out. A support vector machine is employed as a metamodel to increase the computational efficiency. Both individual and compound effects of uncertainties in the input parameters are studied to quantify their effect on the steady-state and dynamic characteristics of the bearing.

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“…The combination of physical and virtual simulation, and thus experimental and computational results, shows high potential for increasing our basic understanding of tribosystems [26,27]. Therefore, this combination can be used for the optimization of critical journal bearing systems, for example, the crankshaft bearings of automotive combustion engines.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Shaft Surface Structures on the Tribological Behavior of Journal Bearings by Physical and Virtual Simulation

et al. 2020

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Optimizing the surface topography of cast iron crankshafts offers the opportunity to use this material as an alternative to steel in high-performance combustion engines. In the past, this was not possible due to the higher wear on bearing shells and the higher friction losses in relation to forged steel shafts. In order to find an optimized shaft micro topography, the friction and wear behavior of steel and cast iron shafts with different surface treatments were compared to each other, using a combined physical (experimental) and a virtual (computational) simulation approach. The experiments were carried out with a rotary tribometer using a journal bearing test configuration with the possibility to test real-life bearing shells and shaft specimens, manufactured from real-life crankshafts. In the experiments, a polished steel shaft with low bearing wear was effective. The optimization of cast iron crankshafts by a novel surface treatment showed a significant reduction of bearing wear in relation to the classical surface finishing procedures of cast iron shafts. A computational simulation approach, considering the real-life micro topography by using the Navier–Stokes equations for the calculation of micro hydrodynamics, supports the assessment of fluid friction. The virtual simulation shows, in accordance to the experimental results, only a minor influence of the investigated shaft topographies on the fluid friction. Further optimization of shaft surfaces for journal bearing systems seems possible only by the usage of patterned micro topographies.

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Theoretical and Experimental Investigations on Transient Run-Up Procedures of Journal Bearings Including Mixed Friction Conditions

Cited by 14 publications

References 28 publications

Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part I: Basic Relations

Operating Behavior of Sliding Planet Gear Bearings for Wind Turbine Gearbox Applications—Part I: Basic Relations

Machine learning-based performance analysis of two-axial-groove hydrodynamic journal bearings

Assessment of Shaft Surface Structures on the Tribological Behavior of Journal Bearings by Physical and Virtual Simulation

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