简介:Thispaperfocusesontheflowcharacteristicandlocalresistanceofnon-Newtonianpowerlawfluidinacurved90°bendpipewithcircularcross-sections,whicharewidelyusedinindustrialapplications.Byemployingnumericalsimulationandtheoreticalanalysisthepropertiesoftheflowandlocalresistanceofpowerlawfluidunderdifferentworkingconditionsareobtained.ToexplorethechangeruletheexperimentiscarriedoutbychangingtheReynoldsnumber,thewallroughnessanddifferentdiameterratioofelbowpipe.ThevariationofthelocalresistancecoefficientwiththeReynoldsnumber,thediameterratioandthewallroughnessispresentedcomprehensivelyinthepaper.TheresultsshowthatthelocalresistanceforcecoefficienthardlychangeswithReynoldsnumberofthepowerlawfluid;thewallroughnesshasasignificantimpactonthelocalresistancecoefficient.Asthepipewallroughnessincreasing,thecoefficientoflocalresistanceforcewillincrease.Themainreasonoftheinfluenceoftheroughnessonthelocalresistancecoefficientistheincreaseoftheeddycurrentregioninthepowerlawfluidflow,whichincreasesthekineticenergydissipationofthemainflow.Thispaperprovidestheoreticalandnumericalmethodstounderstandthelocalresistancepropertyofnon-Newtonianpowerlawfluidinelbowpipes.
简介:Anultrasensitivemagneticfieldsensorbasedonacompactin-fiberMach–Zehnderinterferometer(MZI)createdintwin-corefiber(TCF)isproposed,anditsperformanceisexperimentallydemonstrated.AsectionofTCFwassplicedbetweentwosectionsofstandardsingle-modefibers,andthenamicrochannelwasdrilledthroughonecoreoftheTCFbymeansoffemtosecondlasermicromachining.TheTCFwithonemicrochannelwasthenimmersedinawater-basedFe3O4magneticfluid(MF),formingadirectcomponentofthelightpropagationpath,andthensealedinacapillarytube,achievingamagneticsensingelement,whichmergestheadvantagesofanMZIwithanMF.Experimentswereconductedtoinvestigatethemagneticresponseoftheproposedsensor.Thedevelopedmagneticfieldsensorexhibitsalinearresponsewithinameasurementrangefrom5to9.5mTandanultrahighsensitivityof20.8nm/mT,which,toourbestknowledge,is2ordersofmagnitudegreaterthanotherpreviouslyreportedmagneticsensors.Theproposedsensorisexpectedtooffersignificantpotentialfordetectingweakmagneticfields.