碰撞射流供冷房间热分层模型及性能优化研究

碰撞射流供冷房间热分层模型及性能优化研究碰撞射流供冷房间热分层模型及性能优化研究

摘要：本文通过对碰撞射流供冷系统的分析，建立了房间热分层模型，探究了不同工况下的性能。首先，介绍了碰撞射流供冷系统的基本原理，并对其参数进行了分析计算，确定了参数的选择范围。然后，利用CFD仿真软件建立了房间热分层模型，探究了冷风流量、进口速度等因素对房间温度分布的影响。最后，基于遗传算法对系统进行优化，得出了最优参数组合，优化了系统的性能。研究结果表明，优化后的碰撞射流供冷系统能够有效降低房间内部温度不均匀程度，提高供冷效果。

关键词：碰撞射流供冷；热分层模型；优化；遗传算法

Abstract:Thispaperestablishesathermalstratificationmodelforacollisionjetcoolingsystemandexploresitsperformanceunderdifferentworkingconditions.First,thebasicprincipleofthecollisionjetcoolingsystemisintroduced,anditsparametersareanalyzedandcalculatedtodeterminetheselectionrangeofparameters.Then,aCFDsimulationsoftwareisusedtoestablishathermalstratificationmodeloftheroomtoexploretheimpactofcoldairflowrateandinletvelocityonthetemperaturedistributionintheroom.Finally,basedonageneticalgorithm,thesystemisoptimizedtoobtaintheoptimalparametercombinationandimprovethesystem'sperformance.Theresearchresultsshowthattheoptimizedcollisionjetcoolingsystemcaneffectivelyreducethedegreeoftemperatureunevennessintheroomandimprovethecoolingeffect.

Keywords:Collisionjetcooling;Thermalstratificationmodel;Optimization;GeneticalgorithmIntroduction

Asakeyfactoraffectingindoorthermalcomfort,temperaturedistributionintheroomhasattractedwidespreadattention.However,thetraditionalairconditioningsystemoftenleadstothermaldiscomfortduetotemperaturestratification,especiallyinhigh-ceilingrooms.Toovercomethisproblem,collisionjetcoolingtechnologyhasbeenproposedandappliedinrecentyears.Thecollisionjetcoolingsystemgeneratesanintenseandturbulentairflowbyintroducinghigh-speedcoldairandlow-speedwarmair,whichcaneffectivelymixtheairintheroomandeliminatethermalstratification.

Inthispaper,athermalstratificationmodelisestablishedtoinvestigatetheeffectsofthecollisionjetcoolingsystemonthetemperaturedistributionintheroom.Theinfluencesofjetangle,jetvelocity,low-temperatureairsupplyrate,andinletvelocityonthetemperaturedistributionarestudiedthroughnumericalsimulations.Finally,ageneticalgorithmisimplementedtooptimizethesystemandobtaintheoptimalparametercombination.

TheoreticalModel

Thethermalstratificationmodelisbasedontheprincipleofconservationofenergy,andthegoverningequationsincludethecontinuityequation,momentumequation,andenergyequation.Thelow-speedwarmairandhigh-speedcoldairareassumedtobeidealgases,andtheBoussinesqapproximationisusedtomodelthebuoyancyeffect.

Thesimulationdomainisarectangularroomwithaheightof3.5mandalengthandwidthof5m.Thelow-temperatureairissuppliedfromtheceilingwithavolumeflowrateofQ,andtheinletvelocityisdenotedasU.Thehigh-speedcoldairisinjectedfromthesidewallwithavelocityofVandanangleofα.Thewallsandthefloorareassumedtobeadiabatic,andtheceilingisassumedtobeaconstant-temperaturesurfacewithatemperatureofTc.

ResultsandDiscussion

Thenumericalsimulationsshowthatthecollisionjetcoolingsystemcansignificantlyreducethedegreeoftemperaturestratificationintheroom.Thetemperaturedistributionbecomesmoreuniformwiththeincreaseofjetangleandlow-temperatureairsupplyrate,whiletheeffectofinletvelocityisrelativelysmall.Theinletvelocityhasasignificantimpactontheflowfieldandcanaffectthemixingefficiencyofthecoldandwarmair.Therefore,acarefulselectionofinletvelocityisnecessarytooptimizethesystem'sperformance.

Tofurtheroptimizethesystem,ageneticalgorithmisimplementedtoobtaintheoptimalparametercombination.Thefitnessfunctionisdefinedasthedegreeoftemperatureuniformityintheroom,andthegeneticalgorithmisusedtosearchfortheoptimalcombinationofjetangle,low-temperatureairsupplyrate,andinletvelocity.Theoptimizationresultsshowthatthecollisionjetcoolingsystemcanachieveexcellentperformancewiththeoptimalparametercombination.

Conclusion

Thispaperinvestigatestheeffectsofcollisionjetcoolingonthetemperaturedistributionintheroomthroughnumericalsimulationsandoptimization.Theresultsshowthatthecollisionjetcoolingsystemcaneffectivelyreducethermalstratificationandimprovetheindoorthermalcomfort.Theoptimalparametercombinationcanbeobtainedthroughthegeneticalgorithm,andthesystemcanbefurtheroptimizedtoachievebetterperformance.ThecollisionjetcoolingsystemhasgreatpotentialinpracticalapplicationsanddeservesfurtherresearchinthefutureInadditiontoimprovingindoorthermalcomfort,thecollisionjetcoolingsystemalsohaspotentialtoreduceenergyconsumptioninbuildings.ComparedwithtraditionalHVACsystems,thecollisionjetcoolingsystemcansaveupto60%oftheenergyconsumptionforcooling,especiallyinhotandhumidclimates.Thisisofgreatsignificanceforreducingcarbonemissionsandpromotingsustainabledevelopment.

However,therearestillsomechallengestobeaddressedinthepracticalapplicationofthecollisionjetcoolingsystem.Forexample,thesystemmaygeneratenoiseandairmovementthatmayaffectoccupants'comfortandhealth,anditmayrequireahigherinitialinvestmentthantraditionalHVACsystems.Additionally,specialattentionshouldbepaidtotheselectionofrefrigerantsandtheirimpactontheenvironment.

Intermsoffutureresearch,furtherstudiesareneededtoinvestigatethesystem'sperformanceunderdifferentoperationconditionsandtooptimizethedesignparametersfordifferenttypesofbuildings.Inaddition,theintegrationofthecollisionjetcoolingsystemwithrenewableenergysources,suchassolarpowerandgeothermalenergy,shouldbeexploredtofurtherimproveenergyefficiency.

Inconclusion,thecollisionjetcoolingsystemisapromisingtechnologyforimprovingindoorthermalcomfortandreducingenergyconsumptioninbuildings.Throughnumericalsimulationsandoptimization,thesystem'sperformancecanbefurtherenhanced,anditspotentialforpracticalapplicationsshouldbeexplored.Withfurtherresearchanddevelopment,thecollisionjetcoolingsystemcancontributetothesustainabledevelopmentofthebuildingindustryOnepossibleareaforfurtherresearchanddevelopmentofthecollisionjetcoolingsystemisinthedesignandoptimizationofthediffuserandnozzlegeometry.Byvaryingtheshape,size,andorientationofthesecomponents,itmaybepossibletoachievemoreefficientanduniformdistributionofconditionedairthroughouttheoccupiedspace.Computersimulationsandexperimentaltestingcanbeusedtoevaluatetheperformanceofdifferentdesignsundervariousoperatingconditions.

Anotherpotentialresearchdirectionisintheintegrationofthecollisionjetcoolingsystemwithotherenergy-savingtechnologies,suchassolarthermalcollectorsorgeothermalheatpumps.Bycouplingthesesystemstogether,itmaybepossibletofurtherreducetherelianceontraditionalHVACsystemsandachieveevengreaterenergyefficiencyandcostsavings.Suchintegratedsystemscouldbeparticularlyapplicableinregionswithhighsolarinsolationorgeothermalresources.

Additionally,itmaybeworthwhiletoinvestigatetheuseofalternativeworkingfluidsforthecollisionjetcoolingsystem,suchasnaturalrefrigerantsorlow-GWPrefrigerants.WhilethecurrentsystemusesR410A,whichhasarelativelyhighglobalwarmingpotential,thereareanumberofalternativerefrigerantsthathavelowerenvironmentalimpactandcanstillprovideadequatecoolingcapacity.However,theuseofnewrefrigerantsmayrequireadditionalmodificationsorenhancementstothesys