Dr. Monika IvantysynovaMAHA Professor Fluid Power SystemsDesign and Modeling of Fluid Power SystemsME 597/ABE 591 - Lecture 6MAHA Fluid Power Research CenterPurdue UniversitySICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5912Volumetric and torque efficiencyMeasurement of steady state characteristicsDetermination of derived displacement volumeMeasurement based steady state models Content5Aim:Application of basic equations for calculation of performancedata of pumpsPerformance test circuit designBasic knowledge about the generation of steady state modelsSteady state charcteristics, measurement and modelingSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5913Volumetric LossesTorque LossesAADDEEFFHHIIJJBBBCCCGGGLosses - displacement machinesAxial piston machine – swash plate designSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5914Pump Efficiency6The derived displacement volume can only be determined by measurement Te , np1p2, QeVolumetric efficiency:Torque efficiency (hydraulic-mechanical efficiency):Total efficiency:hmveeinouttTpQPPievVnQwhere Vi…. represents the derived displacement volumeeieihmTVpTT212ppp SICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5915Volumetric Efficiency of a PumpVolumetric efficiency ),,,(ivVnpf v7),( pfDynamic viscosity of fluid:[Pa∙s]ievVnQSeQnVQ maxmaxVVSiQnV minSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59168Volumetric Efficiency of a PumpVolumetric efficiency ),,,(ivVnpf Typical values of dynamic viscosityused in displacement machines:-31212mkg 870 with mm 50mm 10 ssKinematic viscosity [cSt, mm2/s]with:andsPa 0.0087sPa 0435.0 ievVnQSeQnVQ max1SLµQVariable displacement pumpSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5917Torque Efficiency of a Pump),,,(ihmVnpf η9ScpScSpSSSTpCnCnCTTTTT 2SeTVpT 2maxeSeieihmTTTVpTT 12SICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5918Total Efficiency of a Pump),,,(itVnpf 10hmveeinouttTpQPPSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 5919Steady State Characteristics0,700,720,740,760,780,800,820,840,860,880,900,920,940,960 50 100 150 200 250 300 350 400 450 500DIFFERENTIAL PRESSURE [BAR] OVERALL EFFICIENCY BENT AXIS DESIGNSWASH PLATE DESIGNComparison of Efficiencies of Axial Piston Pumpsn=2000 rpm=20 cSt11SICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59110Example Lecture 212The displacement pump with a displacement volume of V=100 cm3/rev isdriven by an electric motor at 1800 rpm. At steady state conditions thepressure difference across the pump is Δp= 380 bar. Determine theeffective flow rate at the pump outlet Qeand the power required to drivethis pump. Assume the following values for efficiency:- volumetric efficiency ηv=0.87- torque efficiency ηhm=0.95Qep2p1n12ppp The effective volume flow rate:1-13136minl 6.156m 00261.087.06011800m10100 ssnVQveNm 62.63695.02m 10100Pa 1038023-65hmihmieVpTTThe effective torque yields:The power required to drive the pump:kW 1206018002Nm 62.63621snTTPeeSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59111Steady State MeasurementThe aim of steady state measurements isdetermination of steady state characteristicsof pumps.Te , np1p2, QeQSiQSeLosses and their dependency on operatingparametersEfficiency and its dependency on operatingparametersEffective torque Teand effective volumetricFlow rate Qe in the whole parameter rangeParameters to be measured:Inlet pressure p1Outlet pressure p2Torque TeShaft speed nVolume flow rate at pump outlet Qe=Q2Temperatures θ1,θ2,θSeUnder stable conditions, allparameters remain constant,including temperatures !14SICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59112SeQnVQ maxSteady State Characteristics15SeTVpT 2maxViderived displacement volume to be determined during measurementsMeasured valueQSmust be calculated usingmeasurement resultsTSmust be calculated usingmeasurement resultsnTPQpPPPeSeSoutin2PS must be calculated using measurement results12ppp SICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59113Derived displacement volumeViVi=Qe/nQeQemeasured values0 0Measurement of effective volume flow rate at pump outletunder defined conditions25Virequired for determination of losses and volumetric and torque efficiencySICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59114EMTest CircuitFlow meterT, nθ1θ2θSeMeasured Values:Inlet pressure p1Outlet pressure p2Torque TShaft speed nVolume flow rate at pump outlet Q2Temperature θ1,θ2,θSe16Additional measuredvalues:Case flow rate QSePressure case line pSeISO 4409Temperature θ1 must remain constant during measurementsPressure relief valveSICFP’05, June 1-3, 2005, Linköping © Dr. Monika IvantysynovaDesign and Modeling of Fluid PowerSystems, ME 597/ABE 59115Steady State MeasurementIn case that Q2is measured in low pressure line, the measuredvalue must be corrected with respect to p2and θ2θ1θ2θ33Q3θSeT 3232321KppQQwith K … bulk modulusßθ…thermal volumetricexpansion