简介:Three-dimensionalseepageindoublefracturedmediawasmodeledinthispaper.Thedeterminationofhydraulicconductivitytensorofrockmassisavitalproblemfortheseawaterintrusionorseawaterencroachmentandseepageoffissuredmedium.Accordingtothegeologicalandhydrogeologicalconditionsforthe2nd-stageconstructionoftheThreeGorgesProject(TGP),thephysicalandmathematicalmodelsforthegroundwatermovementthroughthe3Ddoublefracturedmediaofrockmassduringconstructionwereestablishedinthispaper.Basedondiscontinuity-controlinversetheory,somerelatedparametersofdoublefracturedmediawereinversedwithfluxbeingtheknownquantityandcalibrationofwatertabletheobjectivefunction.Synchronously,theseepagefieldoftheconstructionregionwassystematicallyanalyzedandsimulated,theresultsofwhichexhibitthatthedoublefracturedmediamodeloffracturewatercancomprehensivelyandcorrectlydescribethegeologicalandhydrogeologicalconditionsintheconstructionregion.
简介:Anexperimentalstudywascarriedouttoinvestigatetheinfluenceofdoubletwisted-tapeinserts(DTs)inmicro-fintubes(MFs)onheattransfer,frictionfactorandthermalperformancefactorcharacteristicsofthecompounddevicesinthefollowingconfigurations:(1)twistedtapesactedinthesamedirection(forco-swirl)whileMFandtwistedtapesactedinthesame(parallel)direction(MF-CoDTs:P),(2)twistedtapesactedinthesamedirection(forco-swirl)whilemicro-fintubeandtwistedtapesactedinoppositedirections(MF-CoDTs:O)and(3)twistedtapesactedinoppositedirectionsforcounterswirl(MF-CDTs).TheMFaloneandtheMFequippedwithasingletwistedtapeinparallel/oppositearrangementwerealsoconsideredforcomparison.TheexperimentswereconductedfortheflowswiththeReynoldsnumbersbetween5650and17000,underuniformheatfluxcondition.TheexperimentalresultsindicatethatMF-CDTsinducestrongerswirl/turbulenceflow,resultinginhigherheattransferrate,frictionfactorandthermalperformancefactorthanothercombineddevices.ThethermalperformancefactorsassociatedwiththeuseofMF-CDTswerefoundtobehigherthanthoseassociatedwiththeusesofMF-CoDTs:P,MF-CoDTs:OandMFaloneupto9.3%,6.5%and56.4%,respectively.TheempiricalcorrelationsdevelopedusingthepresentexperimentaldatafortheNusseltnumber,frictionfactorandthermalperformancefactorarealsoreported.