Analysis of the power losses in geared transmissions - measurements and CFD calculations based on open source codes

Concli, Franco; Gorla, C.

doi:10.1533/9781782421955.1131

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…As an example, Ariura et al [10] have measured the impulse power losses of a spur gear system with oil jet lubrication; their results suggested that the impulse power losses consist of the power required to trap and accelerate the oil jet flow in the tooth space. The windage power losses are associated with the pure air or air-lubricant pumping by the gear; especially in the air-oil mixture, the gear suffers from a considerable windage power losses [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis for Wetting Behaviors of an Oil Jet Lubricated Spur Gear

et al. 2022

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As it is widely employed in the aeronautical transmission system, a better understanding of the oil jet lubrication behavior is vital to determine the total system energy consumption. Firstly, this study presents related theoretical models such as the sum of oil jet resistance torque, impingement depth, and wetted area of the oil film for calibrating the physical characteristics of the impact of the oil jet on the gear flank. Then, in terms of the flow phenomenology of the liquid column for the oil jet impact on an isolated spur gear, a detailed transient and spatial flow field analysis becomes available, benefiting from an overset mesh method integrating with a volume-of-fluid (VOF) method. Furthermore, not only the oil jet resistance torque, but also the impingement depth as well as the spatial and temporal evolution of wetted surface by the oil film on the gear tooth given by numerical investigations were compared well with the theoretical calculations.

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Section: Introductionmentioning

confidence: 99%

Numerical Analysis for Wetting Behaviors of an Oil Jet Lubricated Spur Gear

et al. 2022

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“…When the linear speed of the gear is too large, the turbulent flow field distribution in the gear box is complicated, which will produce a large windage moment. A windage moment includes a pressure moment and a viscous moment, of which the pressure moment accounts for the largest proportion [1][2][3][4][5] and can account for more than 90% of the total moment. The power loss caused by the windage moment plays an important role in the total power loss of high-speed gears [6][7][8], and both the windage moment and windage power loss increase exponentially with the increase in the gear speed [9][10][11]; that is, the windage loss of gears cannot be ignored under high-speed conditions.…”

Section: Introductionmentioning

confidence: 99%

CFD Modelling and Numerical Simulation of the Windage Characteristics of a High-Speed Gearbox Based on Negative Pressure Regulation

2023

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Windage power loss plays a leading role in the total power loss of high-speed gears, which seriously affects the transmission efficiency of gear systems and leads to high energy consumption. This paper proposes a negative pressure regulation method to reduce windage power loss. Based on the computational fluid dynamics theory, the flow field distribution and windage power loss in the gearbox under different negative pressure conditions are studied, and the effect of the negative pressure environment and speed on the windage power loss is obtained. In order to further save calculation costs, an optimization algorithm of the BP neural network based on a genetic algorithm is proposed to effectively predict the windage power loss. The results show that the high-speed airflow near the tooth’s surface will produce a large pressure moment, which is the main cause of wind resistance loss. The windage power loss increases with the increase in the negative pressure or speed of the gearbox, but the effect of speed is more obvious. The prediction results of the optimization algorithm are in good agreement with the finite element simulation data and the open literature, which can predict the best parameters for reducing windage power loss.

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“…Concli et al. 8,9,14,36 conducted several studies on the CFD simulation of oil distribution and churning power losses of gearboxes by using the Finite Volume Method. His simulation results show very good agreement with experimental results for the investigated operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of oil distribution and churning gear power losses of gearboxes by smoothed particle hydrodynamics

Hua

Arfaoui²,

Stanić³

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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Sufficient oil supply of all machine elements in gearboxes is usually required to avoid damage during operation. Quite frequently, transmissions are conservatively designed with an oversupply of oil to guarantee operational reliability. An oversupply of oil results in an unnecessarily high amount of oil being kept in motion, which in turn leads to excessive hydraulic gear power losses. In high-speed gearboxes in particular, churning losses can contribute greatly to the total power losses. Further detailed information on the oil distribution in gearboxes is needed in order to increase the efficiency and operational reliability of gearboxes. Computational Fluid Dynamics methods provide a flexible way of investigating oil behaviour in transmissions with almost no restrictions regarding geometry and operating conditions. Generally, there are two main methods of computational fluid dynamics simulation in gearboxes: the traditional finite-volume based method (Eulerian approach) and the mesh-free particle-based method (Lagrangian approach). In this work, a computational fluid dynamics model based on the particle-based smoothed particle hydrodynamics method is built to investigate the oil distribution and churning losses of a dip-lubricated single stage gearbox on an efficiency gear test rig. Results are shown and discussed for different rotational speeds and oil temperatures. The smoothed particle hydrodynamics method provides a high potential of predicting the oil distribution of modern dip-lubricated transmission systems. Comparisons with high-speed camera recordings show good agreement. However, the method shows a need for improvement in churning loss prediction.

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Analysis of the power losses in geared transmissions - measurements and CFD calculations based on open source codes

Cited by 6 publications

References 4 publications

Numerical Analysis for Wetting Behaviors of an Oil Jet Lubricated Spur Gear

Numerical Analysis for Wetting Behaviors of an Oil Jet Lubricated Spur Gear

CFD Modelling and Numerical Simulation of the Windage Characteristics of a High-Speed Gearbox Based on Negative Pressure Regulation

Numerical modelling of oil distribution and churning gear power losses of gearboxes by smoothed particle hydrodynamics

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