Research Papers

Fluid and Dynamics Analyses of a Gerotor Pump Using Various Span Angle Designs

[+] Author and Article Information
Chiu-Fan Hsieh

Department of Mechanical and
Computer-Aided Engineering,
National Formosa University,
64 Wunhua Road,
Huwei, Yunlin, Taiwan, 63201, ROC
e-mail: cfhsieh@nfu.edu.tw

1Corresponding author.

Contributed by the Power Transmission and Gearing Committee of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received November 14, 2011; final manuscript received August 23, 2012; published online October 19, 2012. Assoc. Editor: Prof. Philippe Velex.

J. Mech. Des 134(12), 121003 (Oct 19, 2012) (13 pages) doi:10.1115/1.4007703 History: Received November 14, 2011; Revised August 23, 2012

This paper examines how the span angle design of its tooth profile affects the motion and pumping performance of a gerotor pump whose outer rotor profile is formed by an epicycloid and hypocycloid and whose inner rotor profile is obtainable by the theory of gearing. When the outer rotors have the same volume, the sealing performance of the rotor profile can be assessed using the curvature difference method, which indicates that sealing remains the same across various span angle designs. The tooth profile is built using mathematical models of the rotor, and fluid and dynamics analyses are conducted to predict actual pump operation. The overall fluid analysis, which models both compressibility and cavitation, clearly illustrates the complexity of the fluid flow inside the pump. Comparisons of the results for three separate span angle designs then reveal that the larger the span angle, the higher the area efficiency, outlet pressure, outlet flow rate, outlet flow velocity, and gas volume. A subsequent dynamics analysis further suggests that different span angle designs may lead to diverse contact force distribution on the inner and outer rotors. Hence, the research results provide useful guidelines for rotor design.

Copyright © 2012 by ASME
Your Session has timed out. Please sign back in to continue.


Tsay, C. B., and Yu, C. Y., 1990, “Mathematical Model of Gerotor Pump Applicable to its Characteristic Study,” Trans Chin Inst. Engineers, Series C, 11(4), pp. 385–391.
Beard, J. E., Hall, A. S., and Soedel, W., 1991, “Comparison of Hypotrochoidal and Epitrochoidal Gerotors,” Trans. ASME J. Mech. Des., 113, pp. 133–141. [CrossRef]
Beard, J. E., Yannitell, D. W., and Pennock, G. R., 1992, “The Effect of the Generating Pin Size and Placement on the Curvature and Displacement of Epitrochoidal Gerotors,” Mech. Mach. Theory, 27(4), pp. 373–389. [CrossRef]
Shung, J. B., and Pennock, G. R., 1994, “Geometry for Trochoidal-Type Machines With Conjugate Envelopes,” Mech. Mach. Theory, 29(1), pp. 25–42. [CrossRef]
Litvin, F. L., and Feng, P. H., 1996, “Computerized Design and Generation of Cycloidal Gearings,” Mech. Mach. Theory, 31(7), pp. 891–911. [CrossRef]
Vecchiato, D., Demenego, A., Argyris, J., and Litvin, F. L., 2001, “Geometry of a Cycloidal Pump,” Comput. Methods Appl. Mech. Eng., 190, pp. 2309–2330. [CrossRef]
Litvin, F. L., Demenego, A., and Vecchiato, D., 2001, “Formation by Branches of Envelope to Parametric Families of Surfaces and Curves,” Comput. Methods Appl. Mech. Eng., 190, pp. 4587–4608. [CrossRef]
Demenego, A., Vecchiato, D., Litvin, F. L., Nervegna, N., and Manco, S., 2002, “Design and Simulation of Meshing of a Cycloidal Pump,” Mech. Mach. Theory, 37(3), pp. 311–332. [CrossRef]
Paffoni, B., 2003, “Pressure and Film Thickness in a Trochoidal Hydrostatic Gear Pump,” Proc. Inst. Mech. Eng., Part G: J. Aerosp. Eng., 217(4), pp. 179–187. [CrossRef]
Paffoni, B., Progri, R., and GrasR., 2004, “Teeth Clearance Effects Upon Pressure and Film Thickness in a Trochoidal Hydrostatic Gear Pump,” Proc. Inst. Mech. Eng., Part G: J. Aerosp. Eng., 218(4), pp. 247–256. [CrossRef]
Hsieh, C. F., and Hwang, Y. W., 2007, “Geometric Design for a Gerotor Pump With High Area Efficiency,” Trans. ASME J. Mech. Des., 129, pp. 1269–1277. [CrossRef]
Hsieh, C. F., 2009, “Influence of Gerotor Performance in Varied Geometrical Design Parameters,” Trans. ASME J. Mech. Des., 131(12), p. 121008. [CrossRef]
Yan, J., Yang, D. C. H., and Tong, S. H., 2009, “A New Gerotor Design Method With Switch Angle Assignability,” Trans. ASME J. Mech. Des., 131(1), p. 011006. [CrossRef]
Tong, S. H., Yan, J., and Yang, D. C. H., 2009, “Design of Deviation-Function Based Gerotors,” Mech. Mach. Theory, 44(8), pp. 1595–1606. [CrossRef]
Yang, D. C. H., Yan, J., and Tong, S. H., 2010, “Flowrate Formulation of Deviation Function Based Gerotor Pumps,” Trans. ASME J. Mech. Des., 132(6), p. 064503. [CrossRef]
Gamez-MonteroP. J., CastillaR., KhamashtaM., and CodinaE., 2006, “Contact Problems of a Trochoidal-Gear Pump,” Int. J. Mech. Sci., 48(12), pp. 1471–1480. [CrossRef]
Gamez-Montero, P. J., and CodinaE., 2003, “Contact Stress in a Gerotor Pump,” ASME International Mechanical Engineering Congress and Exposition, November 15–21, Washington, DC, pp.65–71.
Gamez-Montero, P. J., Castilla, R., Mujal, R., Khamashta, M., and Codina, E., 2009, “GEROLAB Package System: Innovative Tool to Design a Trochoidal-Gear Pump,” Trans. ASME J. Mech. Des., 131(7), p. 074502. [CrossRef]
Gamez-Montero, P. J., Garcia-Vilchez, M., Raush, G., Freire, J., and Codina, E., 2012, “Teeth Clearance and Relief Grooves Effects in a Trochoidal-Gear Pump Using New Modules of GeroLAB,” Trans. ASME J. Mech. Des., 134(5), p. 054502. [CrossRef]
Ivanović, L., Devedžić, G., Ćuković, S., and Mirić, N., 2012, “Modeling of the Meshing of Trochoidal Profiles With Clearances,” Trans. ASME J. Mech. Des., 134(4), p. 041003. [CrossRef]
Choi, T. H., Kim, M. S., Lee, G. S., Jung, S. Y., Bae, J. H., and Kim, C., 2012, “Design of Rotor for Internal Gear Pump Using Cycloid and Circular-Arc Curves,” Trans. ASME J. Mech. Des., 134(1), p. 011005. [CrossRef]
Ding, H., Visser, F. C., Jiang, Y., and Furmanczyk, M., 2011, “Demonstration and Validation of a 3D CFD Simulation Tool Predicting Pump Performance and Cavitation for Industrial Applications,” ASME Trans. J. Fluids Eng., 133, p. 011101. [CrossRef]
Litvin, F. L., 1994, Gear Geometry and Applied Theory, Prentice Hall, New York.


Grahic Jump Location
Fig. 1

Design of the outer rotor profile

Grahic Jump Location
Fig. 2

Coordinate systems of the gerotor pump

Grahic Jump Location
Fig. 3

Definition of span angle (a) case 1: span 20, (b) case 2: span 30, and (c) case3: span 40

Grahic Jump Location
Fig. 4

Rotors profiles of three cases

Grahic Jump Location
Fig. 5

Sealing evaluation by the curvature difference analysis

Grahic Jump Location
Fig. 6

Simulation positions for the flow analysis

Grahic Jump Location
Fig. 7

Calculation of dynamic grid and pressure during operations (a), (b), (c), and (d)

Grahic Jump Location
Fig. 8

Y-direction velocity of the seven positions inside the pump (a) P01-P04 and (b) P05–P07

Grahic Jump Location
Fig. 9

Pressure of the seven positions inside the pump (a) P01 and P07, (b) P02 and P06, and (c) P03–P05

Grahic Jump Location
Fig. 10

Y-direction velocity variation of the outlet

Grahic Jump Location
Fig. 11

Pressure variation of the outlet

Grahic Jump Location
Fig. 12

Flow rate variation of the outlet

Grahic Jump Location
Fig. 13

Gas volume in the gerotor pump

Grahic Jump Location
Fig. 14

Given the angular velocity curve of the inner rotor

Grahic Jump Location
Fig. 15

Motion analysis of the outer rotor (a) angular velocity of the outer rotor and (b) angular acceleration of the outer rotor

Grahic Jump Location
Fig. 16

Model of stress analysis in inner and outer rotors (a) inner rotor stress and (b) Outer rotor stress

Grahic Jump Location
Fig. 17

Stress variation of the inner rotor

Grahic Jump Location
Fig. 18

Stress variation of the outer rotor

Grahic Jump Location
Fig. 19

Stress of the inner and outer rotors in span 20 and span 30




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In