Piezoelectric PumpDevelopment Franklin E.Sager Abstract Theprimary objective ofthepiezoelectric pumpprogram isthedevelopment ofenabling pumptechnology forspaceapplications. Pumpsunderdevelopment arecharacterized byreduced mechanical complexity, increased reliability, improved efficiency, reduced volume, andreduced weight, withrespect to conventional pumps. Withacombination ofsponsor andinternal funding, twogenerations ofpump designs werebuiltandtested. Themainproducts weredesignunderstanding andsizingequations, and amarked improvement inpumpperformance asthedesignevolved. Thebasicengineering developed onthisprojecthasbroadaerospace applications. Introduction/Background Conventional state-of-the-art pumps(motorandpump)arecapable ofachieving 18%efficiency inthe conversion ofvoltage andcurrent (in)topressure andflow(out).Conventional pumptechnology has beenunderdevelopment forover100years.Significant improvement forconventional systems is unlikely duetothematurity ofthetechnology. However, piezoelectrically-driven pumptechnology, under development forapproximately 10years,promises reduced mechanical complexity, increased reliability, improved efficiency, reduced volume, andreduced weight, withrespect toconventional pumps. Thisreportcoversworkperformed undertwoSmallBusiness Innovative Research (SBIR)contracts and twoIndependent Research andDevelopment (IR&D)projects directed towardthedevelopment ofpositive displacement piezo-electrically drivenpumps. Theinitialresearch wasmorespecifically directed toward thedevelopment ofaPiezoelectric WaterPumpforUseinExtraVehicular Activities. Theoriginal project consisted ofthreemajorparallel efforts: themechanical designofthepumpdrivemechanism, the electrical designofthedrivecircuitry, andthemechanical designofthepumpitself.StressEngineering Services, Inc.(SES)andOceaneering SpaceSystems, Inc.(OSS)performed themajority ofthework. SEShashadprimary responsibility fortheanalysis andsizingofthedriveblocksandmechanical design ofthepump. OSSwasresponsible forthedriveblockfabrication methodology andtheelectrical design andanalysis. TheCrewandThermal Systems Division attheJohnson SpaceCenter(JSC)inHouston initiated thedevelopment projectasaPhaseISBIR.Theconclusion ofthePhaseIstudy[1]indicated thatitwasfeasible tobuildandoperate apiezoelectric pump. Asafollow-on activity, OSSperformed anIR&Dprojecttoconfirm fabrication processes forthepiezoelectric actuators. NASAawarded aPhaseIISBIRtobuildaworking prototype basedonthesuccessful conclusion ofthePhaseISBIR(September 1993)andthepositive resultsfromthefabrication IR&D project. ThePhaseIISBIRwassuccessfully completed inApril1997.ThePhaseIIprototype wasmade withpiezoelectric polymer films.BasedonresultsfromthePhaseIISBIR,additional IR&Dwasinitiated toinvestigate fabrication techniques and performance characteristics ofhybrid PZT/thermoplastic piezoelectric bender elements. ThesehybridPZT/thermoplastic piezoelectric bender elements aretheprimary components of thesecond prototype. Theywillallowtheoperation ofpiezoelectric devices atoperating voltages on theorderof10V.Thispaperdescribes thetwo Figure1.Bender Element. *Oceaneering SpaceSystems, Houston, TX Proceedings ofthe34_Aerospace Mechanisms Symposium, Goddard SpaceFlightCenter,May10-12,2000 157