1、斯特林發動機斯特林發動機是一種閉循環活塞式熱機，閉循環的意思是工作燃氣一直保存在氣缸內,而開循環則如內燃機和一些蒸氣機需要與大氣交換氣體。斯特林發動機一般被歸為外燃機。切圖以外的菱形驅動器測試配置斯特林發動機的設計：*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。在此設計了置換活塞構造沒有專門建造的再生。介紹斯特林發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:斯特林發動機是一個封閉的循環蓄熱式發動機，氣體工質。“封閉循環”是指工作流體內永久的發動機。工作流體是氣體推動活塞上。這種外部熱發動機可以驅動任何熱源。“再生”是指利用一個內部換熱器稱為再生這增加了發動機的熱效率相比，類似的，但簡單的熱斯特林循環的值得注意的是，其完善的理論效率;然而這還沒有實現的理想仍然是一項巨大的工程挑戰。然而，目前的設計，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。斯特林發動機在目前激動

11、人心的利益為核心的組成部分，國內熱電聯產（熱電聯產）單位，這可能產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，包括布雷頓循環，愛立信斯特林循環或周期。在斯特林發動機已用于小型低功耗應用了近兩個世紀。斯特林發動機繼續使用他們的能力提供機械或電力，加熱或冷卻的應用，熱源和散熱片可用。斯特林發動機背景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限制，例如摩擦、熱傳導性、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、化學能

30、和核能。與內燃機相比，史特林引擎往往維修需求較低，更高效、更安靜、而且更可靠。它們傾向被應用于某些特殊用途以發揚其獨特優點。特別是首要目標非減低每單位功率的投資成本（金錢/千瓦），而是減低引擎產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。然而在一些用途上,適當的本益分析可令史特林引擎優于內燃機引擎。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境問題，史特林引擎的優點愈來愈顯著。對史特林引擎科技提高興趣促進了史特林裝置的研發。其應用涵蓋借由不相容于內燃機的豐富能源抽水、宇基太空航

31、行、發電，像是太陽能、農業廢料還有家庭垃圾。另一個史特林引擎的潛力是，若供應機械功，它可以作為一種熱泵。已有實驗利用風能驅動史特林熱泵作為家用冷暖空調。斯特林發動機功能描述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.發動機運行由于斯特林發動機

44、是一個封閉的循環，它包含一個固定的大規模的天然氣被稱為“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動機。無閥是必要的，不像其他類型的活塞式發動機。在斯特林發動機，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熱冷熱交換器，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，溫度和體積是有關系的。當氣體被加熱，因為它

45、是在一個密封的房間，壓力上升，這對當時行為的權力活塞產生動力中風。當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，從而產生了凈功率輸出。當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。當工作氣體接觸冷戰一方，其壓力低于大氣壓力的氣氛推的活塞和不工作的天然氣。總之，使用斯特林發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量的天然氣，加熱和擴大，冷卻和壓縮，從而熱能轉換為機械能。更大的溫度差異的熱點和冷源，更大的熱效率。最高理論效率相當于卡諾循環,但效率的真正的發動機是只有一小部分的價值，即使是在高度優化的引

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動機在行動非常的低功率發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加壓在大多數高功率斯特林發動機，無論是最低壓力和平均壓力的工作流體高于大氣壓力。這一初步增壓發動機可實現泵，或填補了發動機的壓縮天然氣罐，甚至只是發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量的工作液中的熱力循環。所有的換熱器的尺寸必須適當提供必要的傳熱率。如果換熱器是精心設計，可供應熱通量所需的對流換熱，然后將發動機產生電力中所占的比例平均壓力，因為預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。如同大多數方面的斯特林發動機的設計，優化多元，而且往往有矛盾的要求。35潤滑油和摩擦斯特林發動機和發電機組55千瓦的電力輸出，為熱電聯產的應用。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，可以結合發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，設計者寧愿不潤滑，低摩擦系數材料(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燃機斯特林循環Mainarti

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

49、worldissuesreducetheefficiencyofactualengines,duetolimitsofconvectiveheattransfer,andviscousflow(friction).Therearealsopracticalmechanicalconsiderations,forinstanceasimplekinematiclinkagemaybefavoredoveramorecomplexmechanismneededtoreplicatetheidealizedcycle.主要文章：斯特林循環在理想化或“文字書”斯特林循環是一個熱力循環有兩個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能夠切實執行的引擎-其理論效率相當于這一虛構的卡諾循環。然而現實世界的問題，降低效率，實際的發動機，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系起來可能是有一個更復雜的機制需要復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