scholarly journals Analytical and Experimental Spur Gear Tooth Temperature as Affected by Operating Variables

1981 ◽  
Vol 103 (1) ◽  
pp. 219-226 ◽  
Author(s):  
D. P. Townsend ◽  
L. S. Akin
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Jet Impingement ◽  
Spur Gear ◽  
Constant Load ◽  
Significant Rise ◽  
Transfer Coefficients ◽  
Surface Temperatures ◽  
Jet Penetration ◽  
Oil Jet

A gear tooth temperature analysis was performed using a finite element method combined with a calculated heat input, calculated oil jet impingement depth, and estimated heat transfer coefficients. Experimental measurements of gear tooth average surface temperatures and instantaneous surface temperatures were made with a fast response infrared radiometric microscope. Increased oil jet pressure had a significant effect on both average and peak surface temperatures at both high load and speeds. Increasing the speed at constant load and increasing the load at constant speed causes a significant rise in average and peak surface temperatures of gear teeth. The oil jet pressure required for adequate cooling at high speed and load conditions must be high enough to get full depth penetration of the teeth. Calculated and experimental results were in good agreement with high oil jet penetration but showed poor agreement with low oil jet penetration depth.

Investigation of Oil Jet Impingement on a Rotating Gear Using Lattice Boltzman Method (LBM)

2018 ◽  
Author(s):  
Stephen Ambrose ◽  
Hervé Morvan ◽  
Kathy Simmons
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Fuel Efficiency ◽  
Jet Impingement ◽  
Spur Gear ◽  
Qualitative Comparison ◽  
Particle Hydrodynamics ◽  
Order Of Magnitude ◽  
Aero Engines ◽  
Oil Jet

In the drive for greater increases in fuel efficiency and reductions in CO2 emissions from aero engines, an epicyclic reduction gearbox can be used to break the link between the turbine and fan, enabling the engine to run at a higher bypass ratio. However, even small power losses can generate significant amounts of heat, due to the high loads transmitted from the gearbox. A substantial amount of cooling is required to remove this heat and a large part of this is supplied directly to the gear face. Assessing the performance of coolants and minimising the buildup of oil in the system is therefore a critical stage in the design process. Traditionally, finite volume CFD methods have been used to compute flow and heat transfer solutions. More recently, Lagrangian methods such as Smoothed Particle Hydrodynamics (SPH) have also been applied. The Lattice Boltzman Method (LBM) is a mesoscopic particle based method which uses statistical properties of particles based at each point of a lattice to calculate flow properties. This is a fully transient method and allows for a simple and efficient derivation of LES turbulence properties. In this work the Lattice Bolztman Method is used to investigate the impingement of an oil jet on a rotating spur gear. A comparison of LBM simulations is made against published work using other methods such as SPH and CFD — utilising the Volume of Fluid method — as well as a qualitative comparison with published experimental high speed images. These all show an excellent agreement and the simulations take the same order of magnitude of computational power as 3D single phase SPH, but are fully multiphase and have LES turbulence. This method is then used to investigate how changes to the oil feed delivery rate affect the spreading of the oil jet on the gear tooth and the splashing profiles. The potential for applying this method to other scenarios, such as lubricating and cooling meshing gears, is also discussed.

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears

1975 ◽  
Vol 97 (2) ◽  
pp. 283-288 ◽  
Author(s):  
L. S. Akin ◽  
J. J. Mross ◽  
D. P. Townsend
Keyword(s):  
Motion Picture ◽  
High Speed ◽  
Drop Size ◽  
Gear Tooth ◽  
Jet Flow ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Flow Phenomena ◽  
Oil Jet

Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 using a 8.89-cm- (3.5-in.) pitch dia 8 pitch spur gear at oil pressures from 7 × 104 to 41 × 104 N/m2 (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet so that the impingement depth could be determined. An analytical model was developed for the vectorial impingement depth and for the impingement depth with tooth space windage effects included. The windage effects on the oil jet were small for oil drop size greater than 0.0076 cm (0.003 in.). The analytical impingement depth compared favorably with experimental results above an oil jet pressure of 7 × 104 N/m2 (10 psi). Some of this oil jet penetrates further into the tooth space after impingement. Much of this post impingement oil is thrown out of the tooth space without further contacting the gear teeth.

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears—Out of Mesh Condition

1978 ◽  
Vol 100 (1) ◽  
pp. 61-68 ◽  
Author(s):  
D. P. Townsend ◽  
L. S. Akin
Keyword(s):  
High Speed ◽  
Gear Tooth ◽  
Velocity Ratio ◽  
Jet Impingement ◽  
Gear Ratio ◽  
Experimental Program ◽  
High Speed Photography ◽  
Gear Mesh ◽  
Mesh Condition ◽  
Oil Jet

An analysis was conducted for oil jet lubrication on the disengaging side of a gear mesh. Results of the analysis were computerized and used to determine the oil jet impingement depth for several gear ratios and oil jet to pitch line velocity ratios. An experimental program was conducted on the NASA gear test rig using high-speed photography to experimentally determine the oil jet impingement depth on the disengaging side of mesh. Impingement depth reaches a maximum at gear ratio near 1.5 where chopping by the leading gear tooth limits the impingement depth. The pinion impingement depth is zero above a gear ratio of 1.172 for a jet velocity to pitch time velocity ratio of 1.0 and is similar for other velocity ratios. The impingement depth for gear and pinion are equal and approximately one-half the maximum at a gear ratio of 1.0. Impingement depth on either the gear or pinion may be improved by relocation of the jet from the pitch line or by changing the jet angle. Results of the analysis were verified by experimental results using a high-speed camera and a well lighted oil jet.

Smoothed Particle Hydrodynamics Simulation of Oil-Jet Gear Interaction

2017 ◽  
Author(s):  
Marc C. Keller ◽  
Samuel Braun ◽  
Lars Wieth ◽  
Geoffroy Chaussonnet ◽  
Thilo F. Dauch ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
High Speed ◽  
Single Phase ◽  
Jet Impingement ◽  
Spur Gear ◽  
Computational Time ◽  
Qualitative Comparison ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Oil Jet

In this paper the complex two-phase flow during oil-jet impingement on a rotating spur gear is investigated using the meshless Smoothed Particle Hydrodynamics (SPH) method. A comparison of single-phase SPH to multi-phase SPH simulation and the application of the Volume of Fluid method on the basis of a two-dimensional setup is drawn. The results of the different approaches are compared regarding the predicted flow phenomenology and computational effort. It is shown that the application of single-phase SPH is justified and that this approach is superior in computational time, enabling faster simulations. In a next step, a three-dimensional single-phase SPH setup is exploited to predict the flow phenomena during the impingement of an oil-jet on a spur gear for various jet inclination angles. Thereby, a significant effect of the inclination angle on the oil spreading and splashing process is revealed. Finally, a qualitative comparison to an experimental high-speed image shows good accordance.

Volume of Fluid (VOF) Analysis of Oil-Jet Lubrication for High-Speed Spur Gears Using an Adaptive Meshing Approach

2015 ◽  
Author(s):  
Tommaso Fondelli ◽  
Antonio Andreini ◽  
Riccardo Da Soghe ◽  
Bruno Facchini ◽  
Lorenzo Cipolla
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Adaptive Mesh ◽  
Spur Gear ◽  
Volume Of Fluid ◽  
Adaptive Meshing ◽  
Ansys Fluent ◽  
Injection Angle ◽  
Gear Teeth ◽  
Oil Jet

In high speed gearbox systems, the lubrication is generally provided using nozzles to create small oil jets that feed oil into the meshing zone. It is essential that the gear teeth are properly lubricated and that enough oil gets into the tooth spaces to permit sufficient cooling and prevent gearbox failure. A good understanding of the oil behaviour inside the gearbox is therefore desirable, to minimize lubrication losses and reduce the oil volume involved, and ensure gearbox reliability. In order to reach these objectives, a comprehensive numerical study of a single oil jet impinging radially on a single spur gear teeth has been carried out using the Volume of Fluid (VOF) method. The aims of this study are to evaluate the resistant torque produced by the oil jet lubrication, and to develop a physical understanding of the losses deriving from the oil-gear interaction, studying the droplets and ligaments formation produced by the breaking up of the jet as well as the formation of an oil film on the surface of the teeth. URANS calculations have been performed with the commercial code ANSYS FLUENT and an adaptive mesh approach has been developed as a way of significantly reducing the simulation costs. This method allows an automatic mesh refinement and/or coarsening at the air-oil interface based on the volume of fluid gradient, increasing the accuracy of the predictions of oil break-up as well as minimizing numerical diffusion of the interface. A global sensitivity analysis of adopted models has been carried out and a numerical set-up has been defined. Finally several simulations varying the oil injection angle have been performed, in order to evaluate how this parameter affects the resistant torque and the lubrication performances.

Smoothed Particle Hydrodynamics Simulation of Oil-Jet Gear Interaction1

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Marc C. Keller ◽  
Samuel Braun ◽  
Lars Wieth ◽  
Geoffroy Chaussonnet ◽  
Thilo F. Dauch ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Single Phase ◽  
Jet Impingement ◽  
Spur Gear ◽  
Computational Effort ◽  
Computational Time ◽  
Resistance Torque ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Oil Jet

In this paper, the complex two-phase flow during oil-jet impingement on a rotating spur gear is investigated using the meshless smoothed particle hydrodynamics (SPH) method. On the basis of a two-dimensional setup, a comparison of single-phase SPH to multiphase SPH simulations and the application of the volume of fluid method is drawn. The results of the different approaches are compared regarding the predicted flow phenomenology and computational effort. It is shown that the application of single-phase SPH is justified and that this approach is superior in computational time, enabling faster simulations. In the next step, a three-dimensional single-phase SPH setup is exploited to predict the flow phenomena during the impingement of an oil-jet on a spur gear for three different jet inclination angles. The oil’s flow phenomenology is described and the obtained resistance torque is presented. Thereby, a significant effect of the inclination angle on the oil spreading and splashing process as well as the resistance torque is identified.

Effect of structural design parameters on nonlinear dynamic characteristics of the gear transmission

2021 ◽  
pp. 095440702110294
Author(s):  
Tiancheng Ouyang ◽  
Rui Yang ◽  
Yudong Shen ◽  
Jingxian Chen ◽  
Nan Chen
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Gear Tooth ◽  
Spur Gear ◽  
Operating Conditions ◽  
Design Parameters ◽  
Meshing Stiffness ◽  
Nonlinear Dynamic Characteristics ◽  
Potential Energy Method

The calculation of time-varying meshing stiffness caused by the alternate contacting of the gear tooth is an essential prerequisite to obtain real and effective nonlinear dynamic characteristics of the transmission system, so that the significance of which cannot be overemphasized. Accordingly, this work proposes an improved method to get meshing stiffness with taking fillet-foundation and gear rim deflection into consideration. Compared to the traditional potential energy method, the proposed method has more superior accuracy and performance, and its effectiveness has been further verified by the finite element analytical model. After that, an ideal eight degree of freedoms (DOFs) dynamic model of one stage mass-spring-damper involute spur gear, including lateral and torsional motions, is established to study the dynamic characteristics. Due to the complexity of the gear system operating conditions, we also investigate the influence of various parameters including hub bore radius, transmitting load, and rotation speed on dynamic features, especially in heavy-load and high-speed conditions. From the results, it can be concluded that these parameters will play a prominent role in the spur gear pair dynamic behaviors, providing a certain guidance for gear design.

Analysis of parametric stability for a spur gear pair system considering the effect of extended tooth contact

2009 ◽  
Vol 223 (8) ◽  
pp. 1787-1797 ◽  
Author(s):  
Q Han ◽  
J Wang ◽  
Q Li
Keyword(s):  
High Speed ◽  
Floquet Theory ◽  
Gear Tooth ◽  
Spur Gear ◽  
Parametric Vibration ◽  
Gear Pair ◽  
Mesh Stiffness ◽  
Parametric Stability ◽  
Tooth Contact ◽  
Speed Range

In spur gear dynamic analysis, rectangular waves are often used to approximate the mesh stiffness alternating between one and two pairs of teeth in contact. But in actual practice, extended tooth contact (ETC) occurs due to gear tooth deflection under load. Considering the effect of ETC, the mesh stiffness in the pre-mature and post-mature contact regions is gradually rather than abruptly varying with time, which would influence the parametric stability of the geared system significantly. Therefore, research on parametric stability for a spur gear pair system considering the effect of ETC is carried out in this article. First, a torsional parametric vibration model for a spur gear pair system is established and the periodically time-varying mesh stiffness is approximated linearly by trapezoidal waveforms (with the effect of ETC) and rectangular waves (without the effect of ETC). Then, the Floquet theory for stability analysis (including two key elements: one is the derivation of state transition matrix (STM); the other is the stability criterion for parametric vibration system) is presented briefly. Based on these, the stabilities (stable and unstable regions) of a practically used high-speed and heavy-load spur gear pair with and without taking into account ETC are determined utilizing Floquet theory, respectively, and the differences between the two cases in three ranges of operating speeds for the system (low speed range, middle speed range, and high speed range) are contrasted in detail. In addition, various values of operating torques and mesh damping of the gear pair are also simulated and discussed for their influences upon unstable regions.

Dynamic Behavior of Atmosphere in a Tooth Space of a Spur Gear During Mesh Process From the Viewpoint of Efficient Lubrication

2000 ◽  
Author(s):  
Haruo Houjoh ◽  
Shun-ichi Ohshima ◽  
Shinji Miyata ◽  
Takayuki Takimoto ◽  
Kentaro Maenami
Keyword(s):  
Flow Velocity ◽  
High Speed ◽  
Gear Tooth ◽  
Axial Direction ◽  
Spur Gear ◽  
Excess Energy ◽  
Tooth Surface ◽  
Inertia Effect ◽  
Hot Wire ◽  
Temporal Response

Abstract Lubrication of gear tooth is necessary for cooling as well as reducing friction losses. It is, however, difficult for rather high speed gear because both rotation of the gear itself and associated aero motion interferes the lubrication. In Addition lubrication consumes excess energy due to such kind of churning. To realize efficient lubrication it is worthy to feed lubricant from both ends of tooth in axial direction by the aid of sucking action of tooth spaces just after meshing. This probably make possible that the oil can reach the tooth surface as earlier as possible. Authors investigated the action of air due to pumping action of a spur gear pair by means of both pressure measurement and the hot wire anemometry at the bottom of tooth space to get fundamental data to asses the feasibility of the proposed way. It has been revealed that the behavior is mostly governed by geometric characteristics around the mesh area rather than operational speed, i.e., temporal response of the pressure and flow velocity is proportional to the speed of gear. It has been also found that pressure variation precedes the flow velocity. Sucking phenomena begins when the backlash space passes through the pitch point whereas the pressure is readily negative due to the mass inertia effect of air getting out of the tooth space.

Experimental Investigation on Power Losses due to Oil Jet Lubrication in High Speed Gearing Systems

2017 ◽  
Author(s):  
D. Massini ◽  
T. Fondelli ◽  
B. Facchini ◽  
L. Tarchi ◽  
F. Leonardi
Keyword(s):  
Experimental Investigation ◽  
Mass Flow Rate ◽  
Working Conditions ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Spur Gear ◽  
Lubricating Oil ◽  
Halogen Lamp ◽  
Oil Jet

In order to reduce environmental and climate impact from air traffic, the main effort of aero-engine industry and research community is looking at a continuous increase in gearbox efficiency. With this kind of components every source of loss can be responsible for high heat loads; for this reason oil jet systems are used to provide proper cooling and lubrication of gears tooth surfaces. In the design phase it is important to predict the losses increase due to the lubricating oil jet impact on the spur gear, varying the different geometrical and working parameters such as the jet inclination, distance and the oil mass flow rate and temperature. An experimental investigation was carried out on a novel rotating test rig able to reproduce real engine working conditions in terms of speed, pressure and lubrication system, for a single spur gear. The rig consists of an electric spindle driving a shaft with a spur gear clamped on top. The gear is enclosed in a box where different air pressure conditions can be set and monitored. Pressure transducers and T-type thermocouples placed within the test box were used to measure the gear working conditions. The test box is also equipped with several optical accesses allowing flow field measurements or oil jet visualizations. The driving shaft is composed by two parts connected by a bearingless torquemeter equipped with a speedometer in order to perform torque losses and rotating velocity measurements. Tests were performed without the gear first, in order to separate the final value from the friction losses due to the driving shaft. Windage losses were characterized experimentally for every working condition and the results collected in a simple correlation that was used to separate the losses due to air windage from the ones due to the oil injection. An oil control unit allowed to impose the proper oil pressure and temperature conditions and to measure the mass flow rate. The oil jet was delivered by a spraybar placed within the gearbox, the jet to gear distance and relative angle were varied during the experiments. High speed visualizations were also performed for every test condition in order to deepen the physical understanding of the phenomena and to obtain more information on the lubrication capability of every jet condition. A high speed camera was placed in front of the gear exploiting an optical access while a halogen lamp was used to provide the proper lightening necessary due to the very low exposure time of the acquisitions. The wide experimental database provided, allowed the development of a simple numerical model able to well predict every losses contribution at the various working conditions.

Sign in / Sign up

Export Citation Format

Share Document