简介：Themechanicalenergyequationisafundamentalequationofa1-DmathematicalmodelinHydraulicsandEngineeringFluidMechanics.ThisequationforthetotalflowusedtobededucedbyextendingtheBernoulli’sequationfortheidealfluidinthestreamlinetoastreamtube,andthenrevisedbyconsideringtheviscouseffectandintegratedonthecrosssection.Thisderivationisnotrigorousandtheeffectofturbulenceisnotconsidered.Inthispaper,theenergyequationforthetotalflowisderivedbyusingtheNavier-StokesequationsinFluidMechanics,theresultsareasfollows:(1)Anewenergyequationforsteadychannelflowsofincompressiblehomogeneousliquidisobtained,whichincludesthevariationoftheturbulentkineticenergyalongthechannel,theformulaforthemechanicalenergylossofthetotalflowcanbedetermineddirectlyinthedeductionprocess.(2)Thetheoreticalsolutionofthevelocityfieldforlaminarflowsinarectangularopenchannelisobtainedandthemechanicalenergylossintheenergyequationiscalculated.ThevariationsofthecoefficientofthemechanicalenergylossagainsttheReynoldsnumberandthewidth-depthratioareobtained.(3)Theturbulentflowinarectangularopenchannelissimulatedusing3-DReynoldsaveragedequationsclosedbytheReynoldsstressmodel(RSM),andthevariationsofthecoefficientofthemechanicalenergylossagainsttheReynoldsnumberandthewidth-depthratioarediscussed.

简介：ParticleImageVelocimetry(PIV)techniquewasemployedtostudyexperimentallygas-liquidtwo-phaseflowinanaerationtank.IntermsofthePIVprinciples,analgorithmofPIVbasedontheFastFourierTransformation(FFT)wasworkedout.ThePIVprogramwasdevelopedandverified,andthenwasusedtomeasurethreekindsofstatesinthetestingdevice.Theprogramwasalsousedtocalculateandanalyzetherelatedparameters.Theexperimentaldataindicatethatthebubblesintestingdevicehavethelongestresidenttimeandstrongerturbulentintensityforthegas-liquidtwo-phaseflowinaspecialcase(Case3),resultingingreatincreaseoftheoxygentransferringspeedandefficiency,wherebyprovidingthebasisfortheselectiondesignofaerationtank.