Research Papers: Elastohydrodynamic Lubrication

Thermal Analysis of an Oil Jet-Dry Sump Transmission Gear Under Mixed-Elastohydrodynamic Conditions

[+] Author and Article Information
Ehsan Fatourehchi

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: E.Fatourehchi@lboro.ac.uk

Hamed Shahmohamadi

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: hamedshah@ucla.edu

Mahdi Mohammadpour

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: M.Mohammad-Pour@lboro.ac.uk

Ramin Rahmani

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: R.Rahmani@lboro.ac.uk

Stephanos Theodossiades

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: S.Theodossiades@lboro.ac.uk

Homer Rahnejat

The Wolfson School of Mechanical,
Electrical and Manufacturing Engineering,
Loughborough University,
Loughborough LE11 3TU, UK
e-mail: H.Rahnejat@lboro.ac.uk

1Corresponding author.

Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received February 27, 2017; final manuscript received February 16, 2018; published online April 26, 2018. Assoc. Editor: Wang-Long Li.

J. Tribol 140(5), 051502 (Apr 26, 2018) (11 pages) Paper No: TRIB-17-1061; doi: 10.1115/1.4039567 History: Received February 27, 2017; Revised February 16, 2018

Improved fuel efficiency and reduced emissions are key drivers for modern drivetrain systems. Therefore, in recent years, dry sumps with air–oil mist lubrication have been used for efficient transmission design in order to reduce the churning losses. With dry sumps, appropriate cooling measures should be implemented to dissipate the generated contact heat in an efficient manner. This paper integrates a tribological model with three-dimensional (3D) thermofluid analysis in order to predict the heat generated in the lubricated meshing gear contacts and its dissipation rate by an impinging oil jet in air–oil mist environment. Such an approach has not hitherto been reported in literature. The results show that the generated heat under realistic conditions cannot be entirely dissipated by the impinging oil jet in the air–oil mist transmission casing. Numerical results are used to derive extrapolated regressed equations for heat transfer purposes for time-efficient analysis. These conform well with the detailed numerical results.

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Li, S. , and Kahraman, A. , 2010, “ Prediction of Spur Gear Mechanical Power Losses Using a Transient Elastohydrodynamic Lubrication Model,” Tribol. Trans., 53(4), pp. 554–563. [CrossRef]
Mohammadpour, M. , Theodossiades, S. , Rahnejat, H. , and Kelly, P. , 2014, “ Transmission Efficiency and Noise, Vibration and Harshness Refinement of Differential Hypoid Gear Pairs,” Proc. Inst. Mech. Eng., Part K, 228(1), pp. 19–33.
Mohammadpour, M. , Theodossiades, S. , and Rahnejat, H. , 2014, “ Multiphysics Investigations on the Dynamics of Differential Hypoid Gears,” ASME J. Vib. Acoust., 136(4), p. 041007. [CrossRef]
Talbot, D. C. , Kahraman, A. , and Singh, A. , 2012, “ An Experimental Investigation of the Efficiency of Planetary Gear Sets,” ASME J. Mech. Des., 134(2), p. 021003. [CrossRef]
Mohammadpour, M. , Theodossiades, S. , Rahnejat, H. , and Saunders, T. , 2014, “ Non-Newtonian Mixed Elastohydrodynamics of Differential Hypoid Gears at High Loads,” Meccanica, 49(5), pp. 1115–1138. [CrossRef]
Fatourehchi, E. , Elisaus, V. , Mohammadpour, M. , Theodossiades, S. , and Rahnejat, H. , 2016, “ Efficiency and Durability Predictions of High Performance Racing Transmissions,” SAE Int. J. Passenger Cars-Mech. Syst., 9(3), pp. 1117–1124.
Paouris, L. , Theodossiades, S. , De la Cruz, M. , Rahnejat, H. , Kidson, A. , Hunt, G. , and Barton, W. , 2016, “ Lubrication Analysis and Sub-Surface Stress Field of an Automotive Differential Hypoid Gear Pair Under Dynamic Loading,” Proc. Inst. Mech. Eng., Part C, 230(7–8), pp. 1183–1197. [CrossRef]
Johns-Rahnejat, P. M. , and Gohar, R. , 1997, “ Point Contact Elastohydrodynamic Pressure Distribution and Sub-Surface Stress Field,” International Tri-Annual Conference on Multi-Body Dynamics: Monitoring and Simulation Techniques, Bradford, UK, pp. 161–177.
Seetharaman, S. , and Kahraman, A. , 2009, “ Load-Independent Spin Power Losses of a Spur Gear Pair: Model Formulation,” ASME J. Tribol., 131(2), p. 022201. [CrossRef]
Seetharaman, S. , Kahraman, A. , Moorhead, M. D. , and Petry-Johnson, T. T. , 2009, “ Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation,” ASME J. Tribol., 131(2), p. 022202. [CrossRef]
Changenet, C. , and Velex, P. , 2007, “ A Model for the Prediction of Churning Losses in Geared Transmissions—Preliminary Results,” ASME J. Mech. Des., 129(1), pp. 128–133. [CrossRef]
Dawson, P. H. , 1984, “ Windage Loss in Larger High-Speed Gears,” Proc. Inst. Mech. Eng., Part A, 198(1), pp. 51–59. [CrossRef]
Akin, L. S. , 1973, “ An Interdisciplinary Lubrication Theory for Gears (With Particular Emphasis on the Scuffing Mode of Failure),” ASME J. Eng. Ind., 95(4), pp. 1178–1195. [CrossRef]
Akin, L. S. , Mross, J. J. , and Townsend, D. P. , 1975, “ Study of Lubricant Jet Flow Phenomena in Spur Gears,” ASME J. Lubr. Technol., 97(2), pp. 283–288. [CrossRef]
McCain, J. W. , and Alsandor, E. , 1966, “ Analytical Aspects of Gear Lubrication on the Disengaging Side,” Trans. ASLE, 9(2), pp. 202–211. [CrossRef]
DeWinter, A. , and Blok, H. , 1974, “ Fling-Off Cooling of Gear Teeth,” ASME J. Eng. Ind., 96(1), pp. 60–70. [CrossRef]
Fondelli, T. , Andreini, A. , Da Soghe, R. , Facchini, B. , and Cipolla, L. , 2015, “ Numerical Simulation of Oil Jet Lubrication for High Speed Gears,” Int. J. Aerosp. Eng., 2015, p. 752457. [CrossRef]
Vijayakar, S. , 2000, CALYX Manual, Advanced Numerical Solutions, Inc., Columbus, OH.
Xu, H. , and Kahraman, A. , 2007, “ Prediction of Friction-Related Power Losses of Hypoid Gear Pairs,” Proc. Inst. Mech. Eng., Part K, 221(3), pp. 387–400.
Karagiannis, I. , Theodossiades, S. , and Rahnejat, H. , 2012, “ On the Dynamics of Lubricated Hypoid Gears,” Mech. Mach. Theory., 48, pp. 94–120. [CrossRef]
Evans, C. R. , and Johnson, K. L. , 1986, “ Regimes of Traction in Elastohydrodynamic Lubrication,” Proc. Inst. Mech. Eng., Part C, 200(5), pp. 313–324. [CrossRef]
Crook, A. W. , 1961, “ The Lubrication of Rollers—III: A Theoretical Discussion of Friction and the Temperatures in the Oil Film,” Philos. Trans. R. Soc. London A, 254(1040), pp. 237–258. [CrossRef]
Chittenden, R. J. , Dowson, D. , Dunn, J. F. , and Taylor, C. M. , 1985, “ A Theoretical Analysis of the Isothermal Elastohydrodynamic Lubrication of Concentrated Contacts—II: General Case, With Lubricant Entrainment Along Either Principal Axis of the Hertzian Contact Ellipse or at Some Intermediate Angle,” Proc. R. Soc., Ser. A, 397(1813), pp. 271–294. [CrossRef]
Dowson, D. , and Higginson, G. R. , 1966, Elasto-Hydrodynamic Lubrication: The Fundamentals of Roller and Gear Lubrication, Pergamon Press, London.
Greenwood, J. A. , and Tripp, J. H. , 1970, “ The Contact of Two Nominally Flat Rough Surfaces,” Proc. Inst. Mech. Eng., 185(1), pp. 625–633. [CrossRef]
Teodorescu, M. , Balakrishnan, S. , and Rahnejat, H. , 2005, “ Integrated Tribological Analysis Within a Multi-Physics Approach to System Dynamics,” Tribol. Interface Eng. Ser., 48, pp. 725–737. [CrossRef]
Gohar, R. , and Rahnejat, H. , 2008, Fundamentals of Tribology, Imperial College Press, London. [CrossRef]
Mohammadpour, M. , Theodossiades, S. , and Rahnejat, H. , 2014, “ Transient Mixed Non-Newtonian Thermo-Elastohydrodynamics of Vehicle Differential Hypoid Gears With Starved Partial Counter-Flow Inlet Boundary,” Proc. Inst. Mech. Eng., Part J, 228(10), pp. 1159–1173. [CrossRef]
Hou, Q. , and Zou, Z. , 2005, “ Comparison Between Standard and Renormalization Group k–ε Models in Numerical Simulation of Swirling Flow Tundish,” ISIJ Int., 45(3), pp. 325–330. [CrossRef]
Launder, B. E. , and Spalding, D. B. , 1972, Lectures in Mathematical Models of Turbulence, Academic Press, London.
White, F. M. , 1991, Viscous Fluid Flow, McGraw-Hill, New York.
Winterton, R. H. , 1998, “ Where Did the Dittus and Boelter Equation Come From?,” Int. J. Heat Mass Transfer, 41(4–5), pp. 809–810. [CrossRef]
Hirt, C. W. , and Nichols, B. D. , 1981, “ Volume of Fluid (VOF) Method for the Dynamics of Free Boundaries,” J. Comput. Phys., 39(1), pp. 201–225. [CrossRef]
Brackbill, J. U. , Kothe, D. B. , and Zemach, C. , 1992, “ A Continuum Method for Modeling Surface Tension,” J. Comput. Phys., 100(2), pp. 335–354. [CrossRef]
Eymard, R. , Gallouët, T. , and Herbin, R. , 2000, “ Finite Volume Methods,” Handbook of Numerical Analysis, Vol. VII, Elsevier, Amsterdam, The Netherlands, pp. 713–1020.
Barlow, T. J. , Latham, S. , McCrae, I. S. , and Boulter, P. G. , 2009, “A Reference Book for Driving Cycles for Use in the Measurement of Road Vehicle Emissions,” Wokingham, UK, Report. https://trid.trb.org/view/909274
Norris, J. , Walker, H. , Stones, P. , and Davies, R. , 2011, “ Assessing the Efficacy of Gear Shift Indicators,” AEA, Oxford, UK, Report No. ED49820.
Wang, K. L. , and Cheng, H. S. , 1981, “ A Numerical Solution to the Dynamic Load, Film Thickness, and Surface Temperatures in Spur Gears—Part I: Analysis,” ASME J. Mech. Des., 103(1), pp. 177–187. [CrossRef]
Long, H. , Lord, A. A. , Gethin, D. T. , and Roylance, B. J. , 2003, “ Operating Temperatures of Oil-Lubricated Medium-Speed Gears: Numerical Models and Experimental Results,” Proc. Inst. Mech. Eng., Part G, 217(2), pp. 87–106. [CrossRef]
Townsend, D. P. , and Akin, L. S. , 1981, “ Analytical and Experimental Spur Gear Tooth Temperature as Affected by Operating Variables,” ASME J. Mech. Des., 103(1), pp. 219–226. [CrossRef]
Carper, H. J. , Saavedra, J. J. , and Suwanprateep, T. , 1986, “ Liquid Jet Impingement Cooling of a Rotating Disk,” ASME J. Heat Transfer, 108(3), pp. 540–546. [CrossRef]


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Fig. 1

Schematic representation of the developed model

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Fig. 2

Schematics of specified teeth sections facing the impinging jet

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Fig. 6

Contours of pressure at the outlet boundaries

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Fig. 7

Contours of flow velocity at the outlet boundary

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Fig. 3

Frictional power loss

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Fig. 4

(a) Contours of temperature at the pressure outlet and (b) isobaric temperature distribution at the impinging jet area

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Fig. 5

(a) Contours of oil volume fraction at outlet boundary and (b) oil flow path-lines at in the impinging jet region

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Fig. 9

Heat dissipation variation for a rotating gear surface with oil jet Reynolds number

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Fig. 10

Heat dissipation variation for a rotating gear surface with gear rotational Reynolds numbers

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Fig. 11

Heat dissipation variation for a rotating gear surface with gear surface temperature

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Fig. 12

Effect of gear temperature increase on the heat transfer coefficient of gear flank

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Fig. 8

Heat dissipation from a rotating gear surface for different oil volume fractions



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