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AMESim Heat Generation Model

CAViDS Consortium. AMESim Heat Generation Model. A CAViDS Consortium Project. Advisory Board Report June 7, 2011. CAViDS Consortium. Project Objective. Develop AMESim heat generation modeling capability for gearbox systems which compares favorably with experimental results.

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AMESim Heat Generation Model

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  1. CAViDS Consortium AMESim Heat Generation Model A CAViDS Consortium Project Advisory Board Report June 7, 2011

  2. CAViDS Consortium Project Objective • Develop AMESim heat generation modeling capability for gearbox systems which compares favorably with experimental results.

  3. CAViDS Consortium Work Plan Phase 1: Obtain software and familiarize. (Complete) Phase 2: Model and correlate churning and gear heat generation and temperature rise. 1. Caterpillar FZG test stand model (Complete) 2. Eaton heavy duty transmssion (Underway) 3. Eaton medium duty transmission (Underway)

  4. CAViDS Consortium Technical Status 1. Correlated AMESim temp rise model with Caterpillar Dynasty model of FZG test stand Correlated AMESim temp rise model with Eaton MDT and HDT test data Correlated Changenet based spreadsheet no load loss prediction with MDT and HDT test data Developed LDP based spreadsheet prediction of gear sliding loss for HDT Compared AMESim and Changenet churning loss predictions Compared AMESim and LDP sliding loss predictions

  5. CAViDS Consortium Goals for Last Month • Further evaluate alternative gear sliding loss models • Further verify and develop AMESim heavy duty transmission churning, synchronizer shear, bearing and seal model • Further correlate medium duty churning loss model with Eaton data • Learn to implement Changenet churning and best gear sliding equations directly into AMESim

  6. CAViDS Consortium Last Month’s Accomplishments • Developed uniform Changenet based model for no load losses for MDT and HDT including: • Churning • Synchronizer shear • Bearings

  7. CAViDS Consortium No Load Loss Model Develop heat generation modeling capability for Eaton medium and heavy duty which accurately predicts no load losses and temperature rise on a spin test.

  8. CAViDS Consortium Test Data • All data taken on Galesburg speeder stand • Torque, oil temperature and ambient temperature measured

  9. CAViDS Consortium Loss Prediction Approach Considered following losses 1. Churning - Use Changenet approach 2. Oil shear – Use standard shear formula 3. Bearing – Harris reference

  10. CAViDS Consortium Changenet Churning Loss Equations Loss = C/2 * oil density * speed^2 * pitch radius^3 * submerged area C = 1.366 * (submerged depth/pitch diameter)^0.45 * (oil volume/pitch diameter^3)^0.1 * Froude^-0.6 * Re^-0.21 Re < 6000 C = 3.644 * (submerged depth/pitch diameter)^0.1 * (oil volume/pitch diameter^3)^-0.35 * Froude^-0.6 * (tooth thickness/pitch diameter)^0.85 Re > 6000 • Key assumptions: • Submerged area is defined by dynamic oil height and circumferential submerged area of gear (submerged arc length times gear width). • Reynolds number is peripheral gear speed times gear tooth width divided by kinematic oil viscosity at temperature • Froude number is peripheral gear speed divided by gear tooth width times gravity

  11. CAViDS Consortium Oil Shear Loss Prediction Torque Loss = (S * R * v * A) / d S = speed differential (gear and synchronizer) – m/sec R = synchronizer gage radius - m v = dynamic viscosity of oil – kg/(m*sec) A = synchronizer area – m^2 d = gap between gear and synchronizer - m Torque on drive gear reacted through MS and CS

  12. CAViDS Consortium Bearing Viscous Loss Prediction Viscous Torque = f*(v*n)^0.6667 * d^3 f = constant depending on bearing type v = viscosity in cs n = bearing speed in rpm d = mean bearing diameter in mm

  13. CAViDS Consortium MDT Loss Prediction Spreadsheet

  14. CAViDS Consortium Current Prediction ResultsMedium Duty

  15. CAViDS Consortium Current Prediction ResultsHeavy Duty DirectNormal Fill

  16. CAViDS Consortium Current Prediction ResultsHeavy Duty Direct2 Inch Overfill

  17. CAViDS Consortium Current Prediction ResultsHeavy Duty Direct2 Inch Underfill

  18. CAViDS Consortium Current Prediction ResultsHeavy Duty Overdrive

  19. CAViDS Consortium Current Prediction ResultsHeavy Duty Overdrive

  20. CAViDS Consortium Current Conclusions

  21. CAViDS Consortium AMESim Single Gear Set Churning Loss Model

  22. CAViDS Consortium Churning Loss Equations Changenet Loss = C/2 * oil density * speed^2 * pitch radius^3 * submerged area C = 1.366 * (submerged depth/pitch diameter)^0.45 * (oil volume/pitch diameter^3)^0.1 * Froude^-0.6 * Reynolds^-0.21 AMESim Loss (sides) = Cs * oil density * speed^2 * tooth width * max radius^4 Cs = 0.97 * (submerged volume/oil volume)^-0.576 * (tooth width/max radius)-0.124 * (submerged depth/max radius)^0.74 * Froude^-(0.464+0.037(max radius/submerged depth)) + Re^-0.31 Loss (teeth) = Ct * oil density * speed^2 * tooth width * pitch radius^3 * tooth height Ct = 5623 * (tooth height/8 mm)^-1.5 * (tooth width/8 mm)^-0.36 * Froude^ -0.78 * Reynolds^-0.88

  23. CAViDS Consortium Churning Loss Comparison

  24. CAViDS Consortium HDT Gear Sliding Loss Prediction • Developed spreadsheet based on Kahraman 2007 paper using LDP predicted loads and sliding speeds • Compared to AMESim calculated sliding losses and old experimental results • Developed a set of recommended actions based on results

  25. CAViDS Consortium Gear Mesh Loss PredictionLDP Approach • Use LDP to calculate gear load, sliding and rolling velocity vs. roll angle • Use empirical formulas to determine friction coefficient vs. roll angle • Calculate losses vs. roll angle • Determine average loss through mesh • Correlate with temp rise testing based on model

  26. CAViDS Consortium AMESim Gear Sliding Loss Model

  27. CAViDS Consortium Sliding Loss Formula Comparison LDP Coefficient of Friction = e ^C * Load Intensity ^1.03 * Slide Ratio ^1.04 * Rolling Velocity ^ -0.10 * Dynamic Viscosity ^0.75 * Effective Radius of Curvature ^-0.39 C = --8.92 – 0.35 * Sliding Ratio * Load Intensity * Log (10) (Dynamic Viscosity) +2.81 * e ^ (Sliding Ratio * Load Intensity * Log (10) (Dynamic Viscosity) + 0.62 * e ^Surface finish) AMESim Coefficient of Friction = 0.127 * Ln (0.02912 * Load Intensity) / (Oil Density * Kinematic Viscosity * Sliding Velocity * Rolling Velocity ^2) Changenet (Benedict and Kelly) Same as AMESim except Log (10) (0.2912 *………)

  28. CAViDS Consortium Sliding Loss Comparison • LDP Inverse effect of temperature on losses counterintuitive • LDP model ignores asperity contact • LDP model accounts for surface finish • AMESim model closer to limited test results and shows viscosity effects consistent with intuition

  29. CAViDS Consortium Recommended Further Actions • Study Kahraman’s later (2007 – present) work • Consider using OSU to further develop LDP approach and incorporate into LDP $8000. (Discuss potential funding mechanisms) • Evaluate other formulae referenced in Kahraman 2006 paper • Run dyno testing on heat rise

  30. CAViDS Consortium Next Month • Incorporate churning submodel in AMESim • Evaluate alternative gear sliding models • Continue to evaluate no loss modeling techniques

  31. CAViDS Consortium Notes • Software easy to use • LMS has great support • Capabilities will meet our needs • University license $3000 for year • Changenet churning loss calculations look promising • LDP mesh loss prediction easy to use – need development

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