Determination of oil distribution and churning power loss of gearboxes by finite volume CFD method

Hua, Liang; Jurkschat, Thomas; Lohner, Thomas; Stahl, Karsten

doi:10.1016/j.triboint.2016.12.042

Cited by 99 publications

(90 citation statements)

References 7 publications

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“…Therefore, the proposed approach is more applicable and avoids intervening problems when modeling real-engineering machinery. A method similar to the flank-moving method is the scaling method used by Liu et al (2017). In the scaling method, the gap between the tooth flanks was increased by scaling the pinion and the wheel to 99% of their actual size.…”

Section: Gear Operationmentioning

confidence: 99%

“…This investigation provided a new and simplified CFD method, but it had obvious limitations. Liu, Jurkschat, Lohner, and Stahl (2017) investigated the oil distribution and the churning loss with almost no restrictions on the house shape and operating conditions, and the numerical results were compared with the test results. Concil and Gorla (2017) introduced an innovative meshing methodology to reduce the computational effort when calculating the churning loss in a planetary gearbox.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental investigation of splashing oil flow in a hypoid gearbox

Peng

Liu

Zhong

2018

Engineering Applications of Computational Fluid Mechanics

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The oil distribution and churning loss are the main concerns in the design of a lubrication system for a gear transmission. This article describes a numerical method of simulating the splashing oil flow in a hypoid gearbox, obtaining the oil distribution, and calculating the churning loss. A threedimensional numerical model is built to simulate the complex oil flow when hypoid gears splash oil inside the box. The volume of fluid (VOF) model is applied to describe the oil-air two-phase flow characteristics. In addition, the flank-moving technique is introduced to overcome the difficulty of generating cells in the tooth-meshing zone. To validate the numerical approach, a test rig is designed to observe the oil distribution in the gearbox and measure the churning loss of the hypoid gears. The comprehensive experimental investigation illustrates that the numerical results correspond well with the measured results. The results of this article show that the numerical method can accurately predict the complex oil flow in a hypoid gearbox and provide a numerical approach for investigating the oil flow and churning loss inside real-vehicle axle housing. This model can serve as a design optimization tool in the future. ARTICLE HISTORY

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Section: Gear Operationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of splashing oil flow in a hypoid gearbox

Peng

Liu

Zhong

2018

Engineering Applications of Computational Fluid Mechanics

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“…The hydraulic loss generally includes the churning and squeezing loss in the case of dip-lubrication. Figure 1 exemplifies the churning, squeezing and windage loss in a dip-lubricated gearbox based on CFD simulation results obtained by the model of Liu et al [5]. The no-load gear power loss and the oil flow in gearboxes have been the focus of much research for many years.…”

Section: Introductionmentioning

confidence: 99%

Detailed Investigations on the Oil Flow in Dip-Lubricated Gearboxes by the Finite Volume CFD Method

et al. 2018

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Three main concerns are in the focus of the development of geared transmissions nowadays: load carrying capacity, noise-vibration-harshness (NVH) behavior, and efficiency. Increasing the efficiency of modern gearboxes contributes significantly to the reduction of energy consumption and the saving of resources. Gearboxes are frequently designed conservatively with an oversupply of oil to guarantee operational reliability. An oversupply of oil results in an unnecessarily high amount of oil kept in motion and to high no-load losses. Detailed information on the oil distribution in the early design stages of gearboxes would help to optimize the lubrication and to increase the efficiency. Thereby, CFD (computational fluid dynamics) methods offer a very flexible way to visualize the oil flow inside gearboxes with much fewer restrictions compared to measurements with transparent gearbox designs. In this study, a verified CFD model based on the finite volume method is used to investigate the oil flow in a single-stage gearbox. Different oil viscosities and circumferential speeds are considered. The investigations focus on the oil flow. The gear churning loss, as part of the no-load loss, is additionally considered. Experimental validation is obtained by high-speed camera recordings and measurements at the FZG no-load power loss test rig. The results show very strong agreement between simulation and measurement. The results show that CFD simulations can visualize the oil flow behavior with a very high degree of detail.

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“…Their power losses can be divided into no-load and load-dependent power losses. Whereas the no-load power loss is mainly caused by the circulation of lubricant [1], the load-dependent power loss of gears is determined by sliding velocity, normal force and the coefficient of friction along the path of contact [2,3]. Recent experimental and theoretical investigations have shown that Diamond-Like Carbon (DLC) coatings can quite significantly reduce friction in TEHL contacts (thermo-elastohydrodynamic lubrication).…”

Section: Introductionmentioning

confidence: 99%

TEHL Simulation on the Influence of Lubricants on the Frictional Losses of DLC Coated Gears

2018

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Diamond-Like Carbon (DLC) coatings can reduce fluid friction in TEHL contacts (thermo-elastohydrodynamic lubrication) of meshing gears. This study investigates the influence of different base oils i.e., mineral, polyalphaolefin and polyglycol oil on the friction of DLC coated spur gears. Thereby, a transient TEHL simulation model based on the finite element based full-system approach coupled iteratively with the thermal equations is applied, considering mechanical and thermal properties of the DLC coatings. Results show a clear reduction of fluid friction in DLC coated gears for all considered lubricants. This can be traced back to higher TEHL temperatures for DLC coated gears, which is due to its low thermal inertia resulting in a thermal insulation effect.

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Determination of oil distribution and churning power loss of gearboxes by finite volume CFD method

Cited by 99 publications

References 7 publications

Numerical and experimental investigation of splashing oil flow in a hypoid gearbox

Numerical and experimental investigation of splashing oil flow in a hypoid gearbox

Detailed Investigations on the Oil Flow in Dip-Lubricated Gearboxes by the Finite Volume CFD Method

TEHL Simulation on the Influence of Lubricants on the Frictional Losses of DLC Coated Gears

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