Advanced Modeling Techniques and Innovations in External Gear Pumps

Transcription

1 Advanced Modeling Techniques and Innovations in External Gear Pumps Andrea Vacca Associate Professor Maha Fluid Power Research Center Purdue University, West Lafayette, IN (USA)

2 Contents A. Vacca Advanced Modeling Techniques Slide 2 1. Research on External Gear Pumps 2. External Gear Machines modeling HYGESim (HYdraulic GEar machines Simulator) fluid dynamic features micro-motions of internal parts noise emissions model validation 3. Model Applications Variable delivery flow unit Wedge gear Miniature gear pump for compact electro hydraulic actuators Novel gear profiles for reduced fluid borne noise

3 A. Vacca Advanced Modeling Techniques Slide 3 Motivations Positive displacement machines V Axial Piston Machines Piston Machines e Radial Piston Machines Swash Plate Machines Bent Axis machines In-line Piston Machines Ivantysynova, 2001 ß with external piston support with internal piston support External Gear Gear Machines Annular Gear Vane Machines Internal Gear Screw Machines

4 Motivations External gear machines Slide 4 Pros. Low cost Compact package Tolerance to aeration/cavitation Low fluid borne noise potential Cons. Fixed Displacement Efficiency

5 Past Research Effort Slide 5 Geometrical features and flow pulsations Beecham, 1946 Bonacini, 1961 Castellani, 1967 Fielding et.al 1977 Manring, Kasaragadda, 2003 Inter-teeth meshing pressure Mancó, Nervegna, 1989 Eaton, Edge, 2001 Zardin et al Borghi et al., 2006 Variable displacement Yang, Zhong, 1987 Bussi, 1992 Hoji et al., 2008 Gear machine simulation models Mancó, Nervegna, 1993 Zardin, Borghi, 2008 Falfari, Pelloni, 2007 Edge et al., 2008 Wustmann et al., 2008 Codina et al, Mucchi et al., Gear profile optimization Nagamura et al., 2004 Kollek et al Wang et al. (2011) Huang, Chen, 2008 Noise emissions Latzel, 2012 Mucchi, 2010 Fiebig, 2010

6 and Innovations in External #6 Gear Pumps Slide 6 HYGESim Structure of the model (HYdraulic Gear machines Simulator)

7 Geometrical model A. Vacca Advanced Modeling Techniques #7 HYGESim Slide 7 (HYdraulic Gear machines Simulator)

8 HYGESim Main flow model Slide 8 (HYdraulic Gear machines Simulator) Lumped parameter model Simplified full cavitation model outlet HP inlet LP

9 HYGESim Main flow model Slide 9 (HYdraulic Gear machines Simulator) vs. delivery pressure ripple apparatus torque meter encoder receiver

10 HYGESim Main flow model Slide 10 (HYdraulic Gear machines Simulator) vs Experimental Simulated Delivery Pressure [bar] volumetric efficiency Time [s] outlet pressure pulsations

11 HYGESim Main flow model Slide 11 (HYdraulic Gear machines Simulator) vs. p 2,i V 1,i p 1,i V 2,i q

12 A. Vacca Advanced Modeling Techniques Slide 12 HYGESim (HYdraulic Gear machines Simulator) Main flow model pressure sensor vs p/pmax DPR - simulated DPR - experimental ITSP - simulated ITSP - experimental Angular position [º]

13 HYGESim Lubricating gaps and micro-motions Slide 13 (HYdraulic Gear machines Simulator) Lateral Gap Leakages Radial Gap Wear Fluid shear losses

14 HYGESim Radial gap and micro-motions Slide 14 (HYdraulic Gear machines Simulator) Constant radial gaps good radial sealing wear F R weak radial sealing Variable radial gaps LP operating position HP nominal position

15 HYGESim Radial gap and micro-motions Slide 15 (HYdraulic Gear machines Simulator) Radial forces (pressure, contact force) Radial gaps Journal bearings Casing wear high radial gap HP low radial gap (wear) LP

16 HYGESim Radial gap and micro-motions Slide 16 (HYdraulic Gear machines Simulator) vs. Radial forces (pressure, contact force) Radial gaps Journal bearings Casing wear

17 HYGESim Lateral gap and micro-motions Slide 17 (HYdraulic Gear machines Simulator) lateral bushes (pressure plates) gears casing typical compensating areas seal HP LP lateral lubricating gap

18 HYGESim - TEHD Pressure & Velocity Field Slide 18 Reynolds Equation Diffusive (or static) term Hydrodynamic terms Gap Flow Field Fluid Mechanics

19 HYGESim - TEHD Pressure & Velocity Field Slide 19 Heat Fluxes.. Gap Thermal Effects Heat Transfer Solid Thermo-Elastic Deformation Heat Transfer/ Continuum mechanics Thermo-Elastic Deformation Gap Flow Field Fluid Mechanics Solid Elastic Deformation Continuum Mechanics Force Balance and Solid Components Micro-Motion Rigid body Dynamics

20 HYGESim - TEHD Slide 20 Bushing Micro-Motion+ Film Thickness + Film Pressure

21 HYGESim - TEHD Qualitative comparisons Slide 21 vs. Film thickness prediction: 11cc EGM Film thickness prediction: 25cc EGM Bushing from test pump after operation Bushing from test pump after operation

22 HYGESim - TEHD Film thickness measurements Slide 22 vs. Prototype + Capacitive Sensors Simulation Experimental

23 HYGESim Hydromechanical efficiency Slide 23 vs. Experimental Measurements Losses in the radial gap Losses in the lateral gap Journal bearing losses Contact losses Turbulent losses

24 Virtual Prototyping Slide 24 Discharge groove HP port Two-Phase Optimization Procedure PHASE I Area connection determination PHASE II Groove realization Objective Functions pressure pulsations localized cavitation volumetric efficiency int. pressure peaks Suction groove LP port Finds the optimal set of area connections as a function of the angular rotation of the gears Finds the shape of the grooves that perform like the optimal area curves found in Phase I

25 Virtual Prototyping Slide 25 Two-Phase Optimization Procedure PHASE II Groove realization Finds the shape of the grooves that perform like the optimal area curves found in Phase I

26 Virtual Prototyping Slide 26 Operating Condition 1 Operating Condition 2... Operating Condition N Initialize grid of design parameters FSI-EHD model for lateral lubricating gaps Run simulations using design grid Evaluate objective functions I. Power Losses II. Gap Non Uniformity Index Iterative procedure Find best feasible solution in the current grid Convergence criterion reached? Yes No Define modified new grid Optimized balance area design obtained

27 Compact EH Actuator Miniature pump Slide 27 EHA casing Pump High efficient EHA system layout

28 Virtual Prototyping Miniature pump Details on the miniature gear pump ( 0.1 cm 3 /rev) Slide 28 *Patent filed

29 Surface shaping Slide 29 Wedged Gears Linear wedge on individual gear teeth: Max. wedge depth microns Total Power Loss [W] Pressure [Bar] *Patent filed Nominal Case Wedge Gears

30 Surface shaping Slide 30 Wedged Gears Step Linear wedge on individual gear teeth: Max. wedge depth microns Total Power Loss [W] Pressure [Bar] *Patent filed Nominal Case Wedge Gears

31 Slide 31 Variable Displacement Gear Pump Variable timing concept Inlet groove Outlet groove Outlet Inlet Slider Bearing block

32 Slide 32 Variable Displacement Gear Pump 600 θ TSV - Volume [mm^3] Max. displaced volume D S Min. displaced volume 0 M Angle [ ]

33 Past attempts A. Vacca Advanced Modeling Techniques Slide 33 Variable Displacement Gear Pump D + d *CN , 1987 GB968998, 1960 Methods of varying displacement Vary the inter-axis distance (radial) Vary the effective meshing length of the gears (axial) *MTZ worldwide emagazine, Variable Flow Spur Gear Oil Pump for utility vehicle engines *US , 2001 EP , 1992 US , 2008 US , 2002

34 Casing Slide 34 Variable Displacement Gear Pump Prototype Bearing block 2 End Cover Flange Bearing block 1 Gears Sliders Piston Connecting rods Pressure compensator casing Pressure compensating springs

35 Prototype Slide 35 Variable Displacement Gear Pump *Patent filed

36 Noise prediction & reduction How noise is generated? Fluid borne noise Slide 36 Structure borne noise Airborne noise

37 Noise prediction & reduction HYGESim Acoustic Hydraulic Fluid Slide 37 Air HYGESim FEM -Structural Mesh Modal Analysis BEM Wrapper Mesh Field Point Mesh

38 Noise prediction & reduction Numerical analysis Orifice side pressure oscillation Slide 38 orifice plate Pump side pressure oscillation pump

39 Slide 39 Thank you! Andrea Vacca Advanced Modeling Techniques