斯特林發(fā)動機講解

1、斯特林發(fā)動機斯特林發(fā)動機是一種閉循環(huán)活塞式熱機，閉循環(huán)的意思是工作燃氣一直保存在氣缸內(nèi),而開循環(huán)則如內(nèi)燃機和一些蒸氣機需要與大氣交換氣體。斯特林發(fā)動機一般被歸為外燃機。切圖以外的菱形驅(qū)動器測試配置斯特林發(fā)動機的設(shè)計：*粉紅-熱筒壁*深灰色-冷筒壁（與冷卻進排氣管在黃色）*暗綠色-熱絕緣分開的兩個汽缸結(jié)束*淺綠色-置換活塞*深藍色-功率活塞*淡藍色-曲柄連桿和飛輪沒有表明：熱源和熱匯。在此設(shè)計了置換活塞構(gòu)造沒有專門建造的再生。介紹斯特林發(fā)動機在熱機中的效率目前是最高的，有時可以達到80%。Intheconversionofheatintomechanicalwork,theStirlingeng

2、inehasthepotentialtoachievethehighestefficiencyofanyheatengine.ItcantheoreticallyperformuptothefullCarnotefficiency,althoughnotyetinpractice.Thepracticallimitationsincludethenon-idealpropertiesoftheworkinggas,andmaterialpropertiessuchasfriction,thermalconductivity,tensilestrength,creep,rupturestreng

3、th,andmeltingpoint.TheStirlingenginecanrunonanyheatsource,includingchemical,solar,geothermalandnuclear.TherearemanypossibleimplementationsoftheStirlingengine.Mostfallintothecategoryofreciprocatingpistonengine.Incontrasttointernalcombustionengines,Stirlingengineshavethepotentialtouserenewableheatsour

4、cesmoreeasily,tobequieter,andtobemorereliablewithlowermaintenance.Theyarepreferredforapplicationsthatvaluetheseuniqueadvantages,particularlyifthethecostperunitenergygenerated($/kWh)ismoreimportantthanthecapitalcostperunitpower($/kW).Onthisbasis,Stirlingenginesarecostcompetitiveuptoabout100kW.3Compar

5、edtoaninternalcombustionengineofthesamepowerrating,Stirlingenginescurrentlyhaveahighercapitalcostandareusuallylargerandheavier.Theirlowermaintenancerequirementsmaketheoverallenergycostcomparable.Thethermalefficiencyisalsocomparable(forsmallengines),rangingfrom15%-30%.3Forapplicationssuchasmicro-CHP,

6、aStirlingengineisoftenpreferabletoaninternalcombustionengine.Otherapplicationsincludewaterpumping,space-basedastronautics,andelectricalgenerationfromplentifulenergysourcesthatareincompatiblewiththeinternalcombustionengine,suchassolarenergy,andbiomasssuchasagriculturalwasteandotherwastesuchasdomestic

7、refuse.StirlingshavealsobeenusedasamarineengineinSwedishGotlandclasssubmarines.4HoweverStirlingsaregenerallynotprice-competitiveasanautomobileengine,duetohighcostperunitpower,lowpowerdensityandhighmaterialcosts.Inrecentyears,theadvantagesofStirlingengineshavebecomeincreasinglysignificant,giventheris

8、einliquidfuelpricesandconcernssuchaspeakoilandclimatechange.Stirlingenginesaddresstheseissuesbybeingverycompatiblewithallrenewableenergyandfuelsources.ThesegrowinginterestsinStirlingtechnologyhavefosteredtheongoingresearchanddevelopmentofStirlingdevices,andR&Dbreakthroughshaveinturnincreasedinterest

9、inthetechnology.Ifsuppliedwithmechanicalpower,Stirlingscanfunctioninreverseasaheatpumpforheatingorcooling.ExperimentshavebeenperformedusingwindpowerdrivingaStirlingcycleheatpumpfordomesticheatingandairconditioning.Inthelate1930s,thePhilipsCorporationoftheNetherlandssuccessfullyutilizedtheStirlingcyc

10、leincryogenicapplications.5Basicanalysisisbasedontheclosed-formSchmidtanalysisgoogle翻譯:斯特林發(fā)動機是一個封閉的循環(huán)蓄熱式發(fā)動機，氣體工質(zhì)?！胺忾]循環(huán)”是指工作流體內(nèi)永久的發(fā)動機。工作流體是氣體推動活塞上。這種外部熱發(fā)動機可以驅(qū)動任何熱源?！霸偕笔侵咐靡粋€內(nèi)部換熱器稱為再生這增加了發(fā)動機的熱效率相比，類似的，但簡單的熱斯特林循環(huán)的值得注意的是，其完善的理論效率;然而這還沒有實現(xiàn)的理想仍然是一項巨大的工程挑戰(zhàn)。然而，目前的設(shè)計，指出其效率高，操作安靜和方便，他們可以利用什么否則將廢熱。斯特林發(fā)動機在目前激動

11、人心的利益為核心的組成部分，國內(nèi)熱電聯(lián)產(chǎn)（熱電聯(lián)產(chǎn)）單位，這可能產(chǎn)生重大影響全世界的能源消耗。12空軍是一個許多可能的氣體，可用于在一個斯特林發(fā)動機。所謂“熱空氣引擎”一般用來包含任何熱空氣引擎的工作液。熱空氣引擎可以使用任何一個幾個不同的熱力循環(huán)，包括布雷頓循環(huán)，愛立信斯特林循環(huán)或周期。在斯特林發(fā)動機已用于小型低功耗應(yīng)用了近兩個世紀(jì)。斯特林發(fā)動機繼續(xù)使用他們的能力提供機械或電力，加熱或冷卻的應(yīng)用，熱源和散熱片可用。斯特林發(fā)動機背景NameThoughithadbeensuggestedasearlyas1884thatallclosedcycleairenginesshouldbegener

12、icallycalledStirlingenginesaftertheinventorofthefirstpracticalexample,theideafoundlittlefavourandthevarioustypesonthemarketcontinuedtobeknownbythenameoftheirindividualdesignerormanufacturer.Then,inthe1940s,thePhilipscompanywassearchingforasuitablenameforitsversionoftheairenginewhichbythattimehadalre

13、adybeentestedwithothergases.Rejectingmanysuggestions,includinghotgasengine(gasenginewasalreadyingeneraluseforinternalcombustionenginesrunningongaseousfuels)andexternalcombustionengine(didnotdifferentiatebetweenopenandclosedcycles),PhilipseventuallysettledonStirlingengineinApril1945.Generalacceptance

14、ofthetermfollowedafewyearslater.8EarlyyearsIllustrationtoRobertStirlings1816patentapplicationoftheairenginedesignwhichlatercametobeknownastheStirlingEngine.TheStirlingengine(orStirlingsairengineasitiswasknownatthetime)wasinventedandpatentedbyReverendDr.RobertStirlingin1816.9Itfollowedearlierattempts

15、atmakinganairenginebutwasprobablythefirsttobeputtopracticalusewhenin1818anenginebuiltbyStirlingwasemployedpumpingwaterinaquarry.10ThemainsubjectofStirlingsoriginalpatentwasaheatexchangerwhichhecalledaneconomiserforitsenhancementoffueleconomyinavarietyofapplications.Thepatentalsodescribedindetailthee

16、mploymentofoneformoftheeconomiserinhisuniqueclosed-cycleairenginedesignllinwhichapplicationitisnowgenerallyknownasaregenerator.SubsequentdevelopmentbyRobertStirlingandhisbrotherJames,anengineer,resultedinpatentsforvariousimprovedconfigurationsoftheoriginalengine.Theirpressurisationenhancementhadby18

17、43sufficientlyincreasedpoweroutputenoughtodriveallthemachineryataDundeeironfoundry.12Aswellassavingfuel,theinventorsweremotivatedtocreateasaferalternativetothesteamenginesofthetime,13whoseboilersfrequentlyexplodedcausingmanyinjuriesandfatalities.1415TheneedforStirlingenginestorunatveryhightemperatur

18、estomaximizepowerandefficiencyexposedlimitationsinthematerialsofthedayandthefewenginesthatwerebuiltinthoseearlyyearssufferedunacceptablyfrequentfailures(albeitwithfarlessdisastrousconsequencesthanaboilerexplosion16)-forexample,theDundeefoundryenginewasreplacedbyasteamengineafterthreehotcylinderfailu

19、resinfouryears.17LaternineteenthcenturydevelopmentsSubsequenttothefailureoftheDundeefoundryenginethereisnorecordoftheStirlingbrothershavinganyfurtherinvolvementwithairenginedevelopmentandtheStirlingengineneveragaincompetedwithsteamasanindustrialscalepowersource(steamboilerswerebecomingsafer18andstea

20、menginesmoreefficient,thuspresentinglessofatargettorivalprimemovers).However,fromabout1860smallerenginesoftheStirling/hotairtypewereproducedinsubstantialnumbersfindingapplicationswhereverareliablesourceoflowtomediumpowerwasrequired,suchasraisingwaterorprovidingairforchurchorgans.19Thesegenerallyoper

21、atedatlowertemperaturessoasnottotaxavailablematerials,sowererelativelyinefficient.Buttheirsellingpointwasthat,unlikeasteamengine,theycouldbeoperatedsafelybyanybodycapableofmanagingafire.20Severaltypesremainedinproductionbeyondtheendofthecentury,butapartfromafewminormechanicalimprovementsthedesignoft

22、heStirlingengineingeneralstagnatedduringthisperiod.21TwentiethcenturyrevivalPhilipsMP1002CAStirlinggeneratorof1951DuringtheearlypartofthetwentiethcenturytheroleoftheStirlingengineasadomesticmotor22wasgraduallyusurpedbytheelectricmotorandsmallinternalcombustionenginesuntilbythelate1930sitwaslargelyfo

23、rgotten,onlyproducedfortoysandafewsmallventilatingfans.23AtthistimePhilipswasseekingtoexpandsalesofitsradiosintoareaswhereelectricitywasunavailableandthesupplyofbatteriesuncertain.Philipsmanagementdecidedthatalow-powerportablegeneratorwouldfacilitatesuchsalesandtaskedagroupofengineersatthecompanysre

24、searchlab(theNat.Lab)inEindhoventoevaluatealternatives.AfterasystematiccomparisonofvariousprimemoverstheStirlingenginesquiet(bothaudiblyandintermsofradiointerference)operationandabilitytorunonavarietyofheatsources(commonlampoil-cheapandavailableeverywhere-wasfavoured),theteampickedStirling.24Theywer

25、ealsoawarethat,unlikesteamandinternalcombustionengines,virtuallynoseriousdevelopmentworkhadbeencarriedoutontheStirlingengineformanyyearsandassertedthatmodernmaterialsandknow-howshouldenablegreatimprovements.25Encouragedbytheirfirstexperimentalengine,whichproduced16wattsofshaftpowerfromaboreandstroke

26、of30 x25mm,26Phillipsbeganadevelopmentprogram.ThisworkcontinuedthroughoutWorldWarIIandbythelate1940shandedovertheType10toPhilipssubsidiaryJohandeWittinDordrechttobeproductionisedandincorporatedintoageneratorset.Theresult,ratedat200wattsfromaboreandstrokeof55x27mm,wasdesignatedMP1002CA（knownastheBung

27、alowset）.Productionofaninitialbatchof250beganin1951,butitbecameclearthattheycouldnotbemadeatacompetitivepriceandtheadventoftransistorradioswiththeirmuchlowerpowerrequirementsmeantthattheoriginalrationaleforthesetwasdisappearing.Approximately150ofthesesetswereeventuallyproduced.27Somefoundtheirwayint

28、ouniversityandcollegeengineeringdepartmentsaroundtheworld28givinggenerationsofstudentsavaluableintroductiontotheStirlingengine.PhilipswentontodevelopexperimentalStirlingenginesforawidevarietyofapplicationsandcontinuedtoworkinthefielduntilthelate1970s,butonlyachievedcommercialsuccesswiththereversedSt

29、irlingenginecryocooler.Theydidhowevertakeoutalargenumberofpatentsandamassawealthofinformationwhichtheylicensedtoothercompaniesandwhichformedthebasisofmuchofthedevelopmentworkinthemodernera.29在將熱變成機械功的轉(zhuǎn)換上，史特林引擎在真實的熱機中可達最高的熱效率，至多80%,僅受工作氣體和引擎材料的不理想性質(zhì)限制，例如摩擦、熱傳導(dǎo)性、抗張強度、緩慢、熔點等。此引擎理論上可用任何足量的熱源運行，包括太陽能、化學(xué)能

30、和核能。與內(nèi)燃機相比，史特林引擎往往維修需求較低，更高效、更安靜、而且更可靠。它們傾向被應(yīng)用于某些特殊用途以發(fā)揚其獨特優(yōu)點。特別是首要目標(biāo)非減低每單位功率的投資成本（金錢/千瓦），而是減低引擎產(chǎn)生每單位能量的成本（金錢/度）的時候。在額定功率下，史特林引擎的投資成本目前比內(nèi)燃機引擎高，而且通常更大更重，因此這引擎科技很少單獨以此作為競爭基準(zhǔn)。然而在一些用途上,適當(dāng)?shù)谋疽娣治隹闪钍诽亓忠鎯?yōu)于內(nèi)燃機引擎。近年來，鑒于能源成本普遍上漲，能源短缺和氣候變遷之類的環(huán)境問題，史特林引擎的優(yōu)點愈來愈顯著。對史特林引擎科技提高興趣促進了史特林裝置的研發(fā)。其應(yīng)用涵蓋借由不相容于內(nèi)燃機的豐富能源抽水、宇基太空航

31、行、發(fā)電，像是太陽能、農(nóng)業(yè)廢料還有家庭垃圾。另一個史特林引擎的潛力是，若供應(yīng)機械功，它可以作為一種熱泵。已有實驗利用風(fēng)能驅(qū)動史特林熱泵作為家用冷暖空調(diào)。斯特林發(fā)動機功能描述EngineoperationSincetheStirlingengineisaclosedcycle,itcontainsafixedmassofgascalledtheworkingfluid,mostcommonlyair,hydrogenorhelium.Innormaloperation,theengineissealedandnogasentersorleavestheengine.Novalvesarerequ

32、ired,unlikeothertypesofpistonengines.TheStirlingengine,likemostheat-engines,cyclesthroughfourmainprocesses:cooling,compression,heatingandexpansion.Thisisaccomplishedbymovingthegasbackandforthbetweenhotandcoldheatexchangers,oftenwitharegeneratorbetweentheheaterandcooler.Thehotheatexchangerisinthermal

33、contactwithanexternalheatsource,suchasafuelburner,andthecoldheatexchangerbeinginthermalcontactwithanexternalheatsink,suchasairfins.Achangeingastemperaturewillcauseacorrespondingchangeingaspressure,whilethemotionofthepistoncausesthegastobealternatelyexpandedandcompressed.Thegasfollowsthebehaviordescr

34、ibedbythegaslawswhichdescribehowagasspressure,temperatureandvolumearerelated.Whenthegasisheated,becauseitisinasealedchamber,thepressurerisesandthisthenactsonthepowerpistontoproduceapowerstroke.Whenthegasiscooledthepressuredropsandthismeansthatlessworkneedstobedonebythepistontocompressthegasontheretu

35、rnstroke,thusyieldinganetpoweroutput.Whenonesideofthepistonisopentotheatmosphere,theoperationisslightlydifferent.Asthesealedvolumeofworkinggascomesincontactwiththehotside,itexpands,doingworkonboththepistonandontheatmosphere.Whentheworkinggascontactsthecoldside,itspressuredropsbelowatmosphericpressur

36、eandtheatmospherepushesonthepistonanddoesworkonthegas.Tosummarize,theStirlingengineusesthetemperaturedifferencebetweenitshotendandcoldendtoestablishacycleofafixedmassofgas,heatedandexpanded,andcooledandcompressed,thusconvertingthermalenergyintomechanicalenergy.Thegreaterthetemperaturedifferencebetwe

37、enthehotandcoldsources,thegreaterthethermalefficiency.ThemaximumtheoreticalefficiencyisequivalenttotheCarnotcycle,howevertheefficiencyofrealenginesisonlyafractionofthisvalue,eveninhighlyoptimizedengines.Sterlingenginesmallclear.oggPlayvideoVideoshowingthecompressoranddisplacerofaverysmallStirlingEng

38、ineinactionVerylow-powerengineshavebeenbuiltwhichwillrunonatemperaturedifferenceofaslittleas7C,forexamplebetweenthepalmofahandandthesurroundingair,orbetweenroomtemperatureandmeltingwaterice.303132editPressurizationInmosthighpowerStirlingengines,boththeminimumpressureandmeanpressureoftheworkingfluida

39、reaboveatmosphericpressure.Thisinitialenginepressurizationcanberealizedbyapump,orbyfillingtheenginefromacompressedgastank,orevenjustbysealingtheenginewhenthemeantemperatureislowerthanthemeanoperatingtemperature.Allofthesemethodsincreasethemassofworkingfluidinthethermodynamiccycle.Alloftheheatexchang

40、ersmustbesizedappropriatelytosupplythenecessaryheattransferrates.Iftheheatexchangersarewelldesignedandcansupplytheheatfluxneededforconvectiveheattransfer,thentheenginewillproducepowerinproportiontothemeanpressure,aspredictedbytheWestnumber,andBealenumber.3334Inpractice,themaximumpressureisalsolimite

41、dtothesafepressureofthepressurevessel.LikemostaspectsofStirlingenginedesign,optimizationismultivariate,andoftenhasconflictingrequirements.35editLubricantsandfrictionAStirlingengineandgeneratorsetwith55kWelectricaloutput,forcombinedheatandpowerapplications.Athightemperaturesandpressures,theoxygeninai

42、r-pressurizedcrankcases,orintheworkinggasofhotairengines,cancombinewiththeengineslubricatingoilandexplode.Atleastonepersonhasdiedinsuchanexplosion.36Lubricantscanalsoclogheatexchangers,especiallytheregenerator.Forthesereasons,designersprefernon-lubricated,low-coefficientoffrictionmaterials(suchasRul

43、on(plastic)orgraphite),withlownormal-forcesonthemovingparts,especiallyforslidingseals.Somedesignsavoidslidingsurfacesaltogetherbyusingdiaphragmsforsealedpistons.ThesearesomeofthefactorsthatallowStirlingenginestohavelowermaintenancerequirementsandlongerlifethaninternal-combustionengines.發(fā)動機運行由于斯特林發(fā)動機

44、是一個封閉的循環(huán)，它包含一個固定的大規(guī)模的天然氣被稱為“工作流”，最常見的空氣，氫氣或氦氣。在正常運作，引擎是密封的，沒有氣體進入或離開發(fā)動機。無閥是必要的，不像其他類型的活塞式發(fā)動機。在斯特林發(fā)動機，最喜歡熱引擎，通過4個周期的主要過程：冷卻，壓縮，加熱和擴張。這是通過移動的氣體之間來回?zé)崂錈峤粨Q器，往往與再生之間的加熱器和冷卻器。熱換熱器的熱與外部的熱源，如燃料燃燒器，和冷戰(zhàn)式換熱器是在接觸熱與外部散熱片，如空氣魚翅。改變氣體溫度會引起相應(yīng)的變化，氣體壓力，而運動的活塞造成的天然氣將輪流擴大和壓縮。氣體的行為如下描述了天然氣的法律，說明氣體的壓力，溫度和體積是有關(guān)系的。當(dāng)氣體被加熱，因為它

45、是在一個密封的房間，壓力上升，這對當(dāng)時行為的權(quán)力活塞產(chǎn)生動力中風(fēng)。當(dāng)冷卻氣體的壓力下降，這意味著較少的工作需要做的活塞壓縮氣體返回中風(fēng)，從而產(chǎn)生了凈功率輸出。當(dāng)一方活塞開放的氣氛中，操作稍有不同。由于密封貨量工作氣體接觸的熱點方面，它的擴大，是做人的工作的活塞和氣氛。當(dāng)工作氣體接觸冷戰(zhàn)一方，其壓力低于大氣壓力的氣氛推的活塞和不工作的天然氣?？傊褂盟固亓职l(fā)動機的溫度差異其熱端和冷端建立一個周期的一個固定數(shù)量的天然氣，加熱和擴大，冷卻和壓縮，從而熱能轉(zhuǎn)換為機械能。更大的溫度差異的熱點和冷源，更大的熱效率。最高理論效率相當(dāng)于卡諾循環(huán),但效率的真正的發(fā)動機是只有一小部分的價值，即使是在高度優(yōu)化的引

46、擎。斯特林引擎小clear.ogg視頻顯示壓縮機和置換的一個非常小的斯特林發(fā)動機在行動非常的低功率發(fā)動機已建成這將運行在溫差只有7C，例如棕櫚油之間的手和周圍空氣之間，或室溫和融化水冰。303132加壓在大多數(shù)高功率斯特林發(fā)動機，無論是最低壓力和平均壓力的工作流體高于大氣壓力。這一初步增壓發(fā)動機可實現(xiàn)泵，或填補了發(fā)動機的壓縮天然氣罐，甚至只是發(fā)動機密封時的平均溫度低于平均溫度。所有這些方法提高質(zhì)量的工作液中的熱力循環(huán)。所有的換熱器的尺寸必須適當(dāng)提供必要的傳熱率。如果換熱器是精心設(shè)計，可供應(yīng)熱通量所需的對流換熱，然后將發(fā)動機產(chǎn)生電力中所占的比例平均壓力，因為預(yù)測的一些西方國家和一些比爾。3334

47、在實際上，最大的壓力也是有限的安全壓力，壓力容器。如同大多數(shù)方面的斯特林發(fā)動機的設(shè)計，優(yōu)化多元，而且往往有矛盾的要求。35潤滑油和摩擦斯特林發(fā)動機和發(fā)電機組55千瓦的電力輸出，為熱電聯(lián)產(chǎn)的應(yīng)用。在高溫度和壓力，氧氣在空氣加壓曲軸箱，或在工作氣體的熱空氣引擎，可以結(jié)合發(fā)動機的潤滑油和爆炸。至少有一人已死于這種爆炸。36潤滑油也可以堵塞換熱器，特別是再生。由于這些原因，設(shè)計者寧愿不潤滑，低摩擦系數(shù)材料(如盧倫(塑料)或石墨)，低正常部隊的運動部件，尤其是滑動密封。一些設(shè)計，避免滑動表面完全采用隔膜密封活塞。這些都是一些因素，使斯特林引擎有較低的維修要求和更長的壽命比內(nèi)燃機斯特林循環(huán)Mainarti

48、cle:StirlingcycleTheidealizedortextbookStirlingcycleisathermodynamiccyclewithtwoisochores(constantvolume)andtwoisotherms(constanttemperature).Itisthemostefficientthermodynamiccyclecapableofpracticalimplementationinanengine-itstheoreticalefficiencyequalingthatofthehypotheticalCarnotcycle.Howeverreal-

49、worldissuesreducetheefficiencyofactualengines,duetolimitsofconvectiveheattransfer,andviscousflow(friction).Therearealsopracticalmechanicalconsiderations,forinstanceasimplekinematiclinkagemaybefavoredoveramorecomplexmechanismneededtoreplicatetheidealizedcycle.主要文章：斯特林循環(huán)在理想化或“文字書”斯特林循環(huán)是一個熱力循環(huán)有兩個isocho

50、res（恒容）和兩個等溫線（恒定的溫度）。這是最有效的熱力循環(huán)能夠切實執(zhí)行的引擎-其理論效率相當(dāng)于這一虛構(gòu)的卡諾循環(huán)。然而現(xiàn)實世界的問題，降低效率，實際的發(fā)動機，由于界限的對流換熱和粘性流動（摩擦）。也有實際的機械因素，比如一個簡單的運動聯(lián)系起來可能是有一個更復(fù)雜的機制需要復(fù)制的理想化的周期斯特林改進Mainarticle:RegenerativeheatexchangerInaStirlingengine,theregeneratorisaninternalheatexchangerandtemporaryheatstoreplacedbetweenthehotandcoldspacessu

51、chthattheworkingfluidpassesthroughitfirstinonedirectionthentheother.Itsfunctionistoretainwithinthesystemthatheatwhichwouldotherwisebeexchangedwiththeenvironmentattemperaturesintermediatetothemaximumandminimumcycletemperatures,37thusenablingthethermalefficiencyofthecycletoapproachthelimitingCarnoteff

52、iciencydefinedbythosemaximaandminima.TheprimaryeffectofregenerationinaStirlingengineistogreatlyincreasethethermalefficiencybyrecyclinginternallyheatwhichwouldotherwisepassthroughtheengineirreversibly.Asasecondaryeffect,increasedthermalefficiencypromisesahigherpoweroutputfromagivensetofhotandcoldendh

53、eatexchangers(sinceitisthesewhichusuallylimittheenginesheatthroughput),though,inpracticethisadditionalpowermaynotbefullyrealizedastheadditionaldeadspace(unsweptvolume)andpumpinglossinherentinpracticalregeneratorstendstohavetheoppositeeffect.Theeasiestwaytounderstandtheregenerator,istoseeitasalumpofm

54、atterplacedintheflowpathoftheworkinggasthattheworkinggasheatsandcoolsasitflowsfromonesideofthestirlingenginetotheother.Asthegasleavesthehotsideoftheengine,thenextgoalofthedesigneristocoolthegas.Iftheregeneratormassiscoolatthatpoint,thehotgaswillbecooledslightlybytheregeneratorasitpassesitandthenfurt

55、hercooledwhenthegasgetstotheheatsinkheatexchanger.Theworkingfluidhasthenbeencooledbytwomethods,theregeneratorandthecoldsinkheatexchanger.Thisprocesshaslefttheregeneratorwarm,thatissomeheathasbeenretainedwithintheengineandnotlosttothecoldheatsink.Thefluidmustthenleavethecoldsideoftheengineandthedesig

56、nersgoalistoheatthefluidasmuchaspossible.Thegaspassesthroughthewarmregenerator,whichheatsthegasalittle,andthenthegasgoesontothehotsideoftheenginewhereitheatsupfurther.Asthecoldgasmovedpasttheregeneratoritcooledtheregeneratoralittleleavingitcoolerandreadyforthenextcycle.Theregeneratoristhereforeamass

57、thatisheatedandcooledbetweentheheatsourceandheatsinktemperaturesastheworkingfluidmovesbackandforth.Theregenerator,asaworkingfluidpre-heater,pre-cooler,improvestheabilitytoheatandcooltheworkingfluid.Thisreducestheburdenontheheatsourceandsinkheatexchangersinmovingtheworkingfluidtothemaximumhighandlowt

58、emperatures.Theregeneratorshouldnotlimittheflowoftheworkingfluidasitmovesabouttheengine,anditshouldnotaddadditionalvolumeofworkingfluid,justforthesakeofaddingaregenerator.Designingasuccessfulregeneratorisabalancebetweenhighheattransferwithlowviscouspumpinglossesandlowdeadspace.Theseinherentdesigncon

59、flictsareoneofmanyfactorswhichlimittheefficiencyofpracticalStirlingengines.Atypicaldesignisastackoffinemetalwiremeshes,withlowporositytoreducedeadspace,andwiththewireaxesperpendiculartothegasflowtoreduceconductioninthatdirectionandtomaximizeconvectiveheattransfer.38InanalphaStirlingenginetheregenera

60、torwouldbeplacedintheflowbetweenthehotandcoldcylinders.Inbetaandgammaenginestheregeneratorisusuallyincorporatedintheheadofthedisplacerpiston.Oftenthedisplacerpistonheaditselfactsasalowefficiencyregeneratorwithoutanyadditionaldesignfeatures.TheregeneratoristhekeycomponentinventedbyRobertStirlingandit