Kuongorora Carnot Cycle muMichina yekushandura Simba
Pendauluan
Munyika yeinjiniya, kunyanya muminda yemichina nesimba, hurukuro pamusoro pekushanda zvakanaka kwesimba nguva dzose inyaya huru. Michina yakasiyana-siyana yekushandura simba—yakadai semainjini emhepo, maturbine egasi, mainjini ekupisa mukati, uye masisitimu ekutonhodza—inoedza kushandura simba kubva kune imwe nzira kuenda kune imwe pasina kurasikirwa kukuru. Zvisinei, mitemo yethermodynamics inoisa miganhu mikuru yekuti kushanda zvakanaka kunogona kuwanikwa sei. Pakati pepfungwa dzakasiyana-siyana dzethermodynamic, Carnot cycle ine nzvimbo yakakosha nekuti inotsanangura kutenderera kwakanaka kwazvo kunogona kushanda pakati pematangi maviri ekupisa. Kuongorora kutenderera kweCarnot hakusi kungodzidzira chete, asiwo kunoshanda senzira yekuongorora mashandiro emitambo chaiyo uye kunzwisisa kuti nei pasina injini inogona kudarika kushanda zvakanaka.
Pfungwa huru dzeCarnot Cycle
Kutenderera kweCarnot idenderedzwa rakanaka rethermodynamic rinoshanda nenzira inodzoserwa pakati penzvimbo mbiri dzinopisa: dziva rinopisa rine tembiricha yakakwira (Th) uye dziva rinotonhora rine tembiricha yakaderera (Tc). Rinonzi rinogona kudzoserwa nekuti maitiro ese ari mairi anoitika pasina kukweshana, pasina musiyano wetembiricha wakaganhurirwa, uye pasina kupararira kwesimba. Mukuita, mamiriro aya haagoneke kuawana zvakakwana, asi modhi iyi yakakosha zvikuru pakusarudza muganho wekushanda kwepamusoro-soro kweinjini yekupisa.
Kutenderera kweCarnot kune maitiro mana akatevedzana: maitiro maviri e-isothermal uye maitiro maviri e-adiabatic. Panyama, kutenderera kunogona kufungidzirwa sekunoitika mu-piston-cylinder ine mvura inoshanda zvakanaka (semuenzaniso, gasi yakakodzera), kunyange zvazvo nheyo dzacho dzichishanda kune chero rudzi rwemvura inoshanda.
Maitiro mana muCarnot Cycle
1. Kuwedzera kweIsothermal (1–2) paTembiricha Th
Muchikamu chekutanga, sisitimu yacho inenge yakabatana nedura rinopisa pakupisa kweTh. Mvura iri kushanda inowedzerwa ne isothermal expansion, zvichireva kuti tembiricha yayo inoramba yakadaro. Kuti tembiricha irambe iripo, sisitimu inotora kupisa (Qh) kubva mudura rinopisa. Munguva yekuwedzera, piston inofamba ichienda kunze, uye sisitimu inoshanda pane zvakakomberedza. Nekuti maitiro acho anodzoserwa, kupisa kunouya kuno "gadziriswa" zvachose kuti kugadzire basa uku kuchichengetedza tembiricha yakafanana.
2. Kuwedzera kweAdiabatic (2–3) kubva kuTh kuenda kuTc
Kana kuwedzera kwemafuta ekunze kwapera, sisitimu inobviswa pamoto kuitira kuti pasave nekuchinjana kwekupisa. Maitiro aya anonzi adiabatic. Mvura inoshanda inoramba ichikura, ichishanda, asi nekuda kwekuti hapana kupisa kunowedzerwa, simba rayo remukati rinoderera, saka tembiricha yesisitimu inoderera kubva paTh kuenda kuTc.
3. Kudzvanywa kweIsothermal (3–4) paTembiricha Tc
Muchikamu chechitatu, sisitimu iyi inosangana nedura rinotonhora pakupisa kweTc. Sisitimu iyi inomanikidzwa neisothermal, zvichiita kuti tembiricha yayo isarambe yakafanana. Kuti tembiricha isakwire panguva yekumanikidzwa, sisitimu iyi inofanira kuburitsa kupisa (Qc) mudura rinotonhora. Muchikamu chino, nzvimbo dzakakomberedza dzinoshanda pasisitimu iyi.
4. Kudzvanywa kweAdiabatic (4–1) kubva kuTc kuenda kuTh
Danho rekupedzisira i adiabatic compression, uko system inoparadzaniswa zvakare nekupisa. Kudzvanywa kunowedzera tembiricha yemvura inoshanda kubva paTc kudzokera kuTh pasina kuchinjana kwekupisa. Mushure mekusvika pamamiriro ekutanga, kutenderera kunodzokorora.
Maitiro mana aya anoumba kutenderera kunogadzira basa remambure panguva imwe chete.
Kumiririrwa paP–V neT–S Diagrams
Kuti unzwisise kutenderera kweCarnot nemaziso, madhayagiramu maviri anowanzoshandiswa ndeaya:
1. Dhayagiramu yeP–V (pressure–volume):
– Maitiro eIsothermal anoonekwa semakori ehyperbolic (emagasi akakodzera).
- Maitiro eAdiabatic "anodzika" kupfuura isothermal.
- Nzvimbo iri mudhayagiramu yeP–V inomiririra basa remambure rinogadzirwa padenderedzwa rega rega.
2. Dhayagiramu yeT–S (tembiricha–entropy):
– Maitiro eIsothermal anoratidzwa semitsara yakatambanuka (constant T).
- Maitiro ekuchinja adiabatic anoratidzwa semutsetse wakamira (S isingachinji).
- Mudhayagiramu iyi, kupisa kunonyudzwa uye kurambwa kunogona kuverengerwa zvakananga:
– Qh = Th × ΔS
– Qc = Tc × ΔS
Sezvo ΔS mu "kumusoro" uye "pasi" maitiro e-isothermal akaenzana (anodzoserwa), ongororo yekushanda kwayo inova yakanaka kwazvo.
Kushanda Nesimba KweCarnot Cycle
Kushanda zvakanaka kweinjini yekupisa kunotsanangurwa sechiyero chebasa remagetsi rinogadzirwa nekupisa kunotorwa kubva mudura rinopisa:
\[
\eta = \frac{W_{net}}{Q_h} = 1 – \frac{Q_c}{Q_h}
\]
Kune kutenderera kweCarnot kunodzoserwa, hukama hune:
\[
\frac{Q_c}{Q_h} = \frac{T_c}{T_h}
\]
Saka kushanda zvakanaka kweCarnot kunova:
\[
\eta_{Carnot} = 1 – \frac{T_c}{T_h}
\]
Fomura iyi inokosha zvikuru nekuti inoratidza kuti kushanda zvakanaka kwazvo kunoonekwa chete nekupisa kwakakwana (muKelvin) kwematangi maviri aya, kwete nerudzi rwemvura inoshanda kana magadzirirwo einjini.
Zvinokonzera Kushanda Zvakanaka kweCarnot
1. Kuwedzera Th kunowedzera kushanda zvakanaka.
Kana tembiricha yechinhu chinopisa yakakwira, basa rinogona kuitwa rinokurawo.
2. Kuderedza Tc kunowedzera kushanda zvakanaka.
Kana tembiricha yekubuda kwemhepo yakadzikira, simba shoma rinofanira kubviswa.
3. Kushanda zvakanaka hakumbofi kwakareba 100% seTc > 0 K.
Kuti uwane kushanda zvakanaka kwe100%, Tc = 0 K inodiwa, izvo zvisingaite mumuviri.
Kutenderera kweCarnot seMuganho Wakakodzera weInjini Yechokwadi
Injini chaidzo dzine hunhu husingadzoreki: kukweshana kwemagetsi, kurasikirwa nekumanikidzwa, kutamiswa kwekupisa pamusoro pemusiyano wekupisa wakaganhurirwa, uye maitiro ekupisa asina kunaka. Zvese izvi zvinowedzera entropy yese uye zvinoita kuti kushanda kwayo kuve kwakaderera pane muganho weCarnot.
Kunyange zvakadaro, Carnot cycle inobatsira sechiyereso. Mainjiniya vanogona kuverenga kushanda kweCarnot mumamiriro ezvinhu ekushanda uye vobva vaenzanisa nekushanda chaiko kuti vaone kuti sisitimu yacho iri kure zvakadii neyakanaka. Semuenzaniso, chitofu chemagetsi chemazuva ano chinogona kushanda zvakanaka ne35–45%, nepo kushanda zvakanaka kweCarnot pakupisa kwebhoyila necondenser kungave kwakakwira. Musiyano uyu unoratidza mukana wekuvandudza—kunyange hazvo mipata yese isingakwanise kuvharwa nekuda kwezvinhu, kuchengetedzeka, uye mitengo.
Kukosha kweMichina yeKushandura Simba Yemazuva Ano
Pfungwa yeCarnot ndiyo hwaro hwekuvandudzwa nekuongorora matekinoroji akasiyana-siyana, anosanganisira:
1. Zvivakwa zvemagetsi zvinopisa:
Kana tembiricha yekushanda kweturbine yakakwira (semuenzaniso muturbine yegesi ine zvinhu zvinodzivirira kupisa), kushanda kwayo kunowanzowedzera nekuti inosvika pamuganho weCarnot.
2. Sisitimu yekutonhodza uye pombi yekupisa:
Carnot inoshandawo kune reverse Carnot cycle, iyo inopa muganho wepamusoro wekushanda (COP) kwemafiriji nemapombi ekupisa.
3. Uinjiniya hwemasisitimu esimba anogarika:
Muzviteshi zvemagetsi zvinopisa zvakanyanya, zviteshi zvebiomass, kana kuti kudzoreredza kupisa kwemarara emaindasitiri, musiyano mudiki wekupisa (kwete wakanyanya kukwira kweTh) unokonzera kushanda kwakaderera kweCarnot. Izvi zvinotsanangura kuti sei masisitimu ekudzoreredza kupisa kwepasi anowanzo kukodzera kupisa zvakananga pane kushandurwa kuita magetsi.
Mhedziso
Kutenderera kweCarnot imhando yakarongwa inoratidza muganho wepamusoro wekushanda zvakanaka kweinjini yekupisa inoshanda pakati pematangi maviri ekupisa. Nemaitiro mana anodzokororwa — maviri e-isothermal uye maviri e-adiabatic — kutenderera uku kunoburitsa kutaura kuri nyore asi kune simba kwekushanda zvakanaka: \(\eta_{Carnot} = 1 – \frac{T_c}{T_h}\). Ongororo iyi inosimbisa kuti kushanda zvakanaka kunoenderana chete nekupisa kwakakwana, uye kuti hapana injini chaiyo inogona kudarika muganho uyu nekuda kwekusachinjika. Kunyangwe Carnot isingakwanise kuzadzikiswa zvakakwana, pfungwa dzake ihwaro hwakakosha hwekugadzira, kuongorora, uye hunyanzvi hwemichina yemazuva ano yekushandura simba, uye inobatsira mainjiniya kunzwisisa nzira huru yekuvandudza kushanda zvakanaka: kukwidza tembiricha inobva pakupisa uye kudzikisa tembiricha yeutsi mukati memiganhu inokwanisika yezvinhu uye yehupfumi.
