Umthetho Wokuqala We-Thermodynamics Ekuhlaziyweni Kwemishini Yezimboni
Ngemuva komsindo wama-turbine, ukushisa kwama-boiler furnaces, kanye nokuvunguza kwama-compressor ezimbonini, kunesimiso esisodwa esiyisisekelo esihlala sikhona: Umthetho Wokuqala We-Thermodynamics. Lo mthetho uyisisekelo sokuqonda ukuthi amandla ahamba kanjani futhi ashintsha kanjani ngaphakathi kwemishini yezimboni. Ngokuwuqonda kahle, onjiniyela bangakwazi ukubala izidingo zikaphethiloli, balinganise ukusebenza kahle, baklame izinhlelo zokupholisa, futhi bahlole ngisho nokuchitha amandla emishinini yokukhiqiza. Lesi sihloko sixoxa ngemibono, izibalo ezibalulekile, kanye nezibonelo zokusetshenziswa koMthetho Wokuqala We-Thermodynamics ekuhlaziyweni komshini wezimboni.
1. Ukuqonda Umthetho Wokuqala We-Thermodynamics
Umthetho Wokuqala We-Thermodynamics empeleni umthetho wokulondolozwa kwamandla. Amandla awakwazi ukudalwa noma ukubhujiswa; angadluliselwa kuphela kusuka ohlelweni olulodwa kuya kolunye noma aguqulwe kusuka kolunye uhlobo aye kolunye. Ngokwesimo se-thermodynamics, izinhlobo zamandla ezivame ukuxoxwa ngazo yilezi:
– Ukushisa (ukushisa, Q): amandla adluliselwa ngenxa yokwehluka kwezinga lokushisa.
– Umsebenzi (W): amandla adluliselwa ngenxa yamandla abangela ukufuduka, isibonelo umsebenzi weshafti ku-turbine noma i-compressor.
– Amandla angaphakathi (U): amandla amancane kakhulu entweni ethile (ahlobene nokushisa, isigaba, kanye nokusebenzisana kwama-molecule).
– Izinto ezibalulekile ezengeziwe ohlelweni lokugeleza: amandla e-kinetic (KE) kanye namandla angase abe khona (PE).
Ngamazwi alula, uMthetho Wokuqala uthi: ushintsho lwamandla ohlelweni lulingana nokufakwa kwamandla ngaphandle kokukhishwa kwamandla.
2. Izinhlelo ze-Thermodynamic eMishini Yezimboni
Ekuhlaziyweni kwemishini yezimboni, sivame ukukhetha olunye lwezinhlobo ezimbili zezinhlelo:
1. Uhlelo oluvaliwe
Isisindo asiweqi imingcele yesistimu, kodwa amandla (ukushisa/umsebenzi) angadluliswa. Isibonelo: i-cylinder-piston kwezinye izinqubo ze-batch (isb., ukuhlolwa kwelebhu noma izinqubo ezikhethekile).
2. Vula uhlelo / ivolumu yokulawula
Ubuningi namandla kungadlula imingcele. Lokhu kuvame kakhulu embonini: ama-turbine, ama-compressor, amaphampu, ama-boiler, ama-condenser, ama-heat exchanger, ama-nozzle, ama-diffuser, namapayipi.
Iningi lemishini yokukhiqiza lihlaziywa njengomthamo wokulawula ngaphansi kwezimo ezizinzile, okusho ukuthi izinga lokugeleza kanye nezakhiwo zoketshezi azishintshi ngokuhamba kwesikhathi nganoma yisiphi isikhathi.
3. Isibalo Esijwayelekile Somthetho Wokuqala We-Thermodynamics
3.1. Kwezinhlelo ezivaliwe
Isibalo esiyisisekelo:
\[
\Delta E = Q – W
\]
lapho \(\Delta E\) ifaka phakathi izinguquko emandleni angaphakathi, e-kinetic, kanye namandla angase abe khona. Ezimweni eziningi ezingokoqobo, izinguquko emandleni e-kinetic kanye namandla angase abe khona azinakwa ukuze:
\[
\Delta U = Q – W
\]
Incazelo: ukungena kokushisa kwandisa amandla angaphakathi, kuyilapho umsebenzi owenziwa uhlelo unciphisa amandla angaphakathi (kuye ngokuthi uphawu lubekwe kanjani, kodwa ubunjiniyela obujwayelekile buthi: Ukungena kuka-Q kuhle, ukuphuma kuka-W (okukhiqizwa uhlelo) kuhle).
3.2. Kwezinhlelo ezivulekile (ukulawula ivolumu)
Ukuze uthole ukugeleza okuzinzile kwe-one-in-one-out, ifomu elivame ukusetshenziswa yileli:
\[
\dot{Q} – \dot{W} = \dot{m}\left[(h_2-h_1) + \frac{V_2^2 – V_1^2}{2} + g(z_2-z_1)\right]
\]
Imininingwane:
– \(\dot{Q}\): izinga lokudlulisa ukushisa (kW)
– \(\dot{W}\): izinga lokusebenza (kW), ngokuvamile ngesimo somsebenzi weshaft
– \(\dot{m}\): izinga lokugeleza kwesisindo (kg/s)
– \(h\): i-enthalpy ethile (kJ/kg)
– \(V\): ijubane lokugeleza (m/s)
– \(z\): ukuphakama (m)
Emishinini eminingi yezimboni, izinguquko ekuphakameni kanye namandla e-kinetic zincane kakhulu uma kuqhathaniswa noshintsho ku-enthalpy, ngakho-ke zenziwa lula ukuze:
\[
\dot{Q} – \dot{W} \approx \dot{m}(h_2-h_1)
\]
Yilolu hlobo olulula olwenza uMthetho Wokuqala ube usizo kangaka: ngedatha ye-inlet-outlet enthalpy kuphela, singalinganisa izidingo zokushisa noma zamandla zomshafti.
4. Ukusetshenziswa Kwemishini Yezimboni
4.1. I-turbine yomusi noma i-turbine yegesi
Ama-turbine aguqula amandla okushisa oketshezi abe umsebenzi womgodi. Kwi-turbine yesimo esizinzile, ngokuvamile kucatshangwa ukuthi iyi-adiabatic (\(\dot{Q}\approx 0\)):
\[
-\dot{W} \approx \dot{m}(h_2-h_1)
\]
Njengoba \(h_2 < h_1\) (ukwehla kwe-enthalpy), khona-ke \(\dot{W}\) ilungile njengamandla akhiqizwayo. Kusukela lapha, amandla e-turbine angabalwa uma izinga lokugeleza kwesisindo kanye nokwehla kwe-enthalpy kwaziwa ngokusekelwe kumathebula esitimu noma idatha yempahla yegesi. Izinzuzo zezimboni: ukubalwa kokukhishwa kwamandla, ukuhlolwa kokusebenza kahle kwe-isentropic ye-turbine, kanye nokulinganisa ukusetshenziswa kwesitimu nge-kWh. 4.2. I-Air compressor I-compressor idinga umsebenzi we-shaft ukwandisa ingcindezi ukuze i-enthalpy ikhuphuke (\(h_2>h_1\)). Kwi-compressor ye-adiabatic:
\[
\dot{W}_{in} \approx \dot{m}(h_2-h_1)
\]
Lokhu kusho ukuthi inani lamandla kagesi adingekayo yi-compressor linqunywa ukwanda kwe-enthalpy, okuthonywa yisilinganiso sokucindezela, izinga lokushisa lokungena, kanye nokusebenza kahle kokucindezela.
Izinzuzo zezimboni: ukunquma imininingwane yemoto, ukubala izindleko zamandla okucindezela, kanye nokuqhathanisa ama-compressor esigaba esisodwa vs. amaningi ane-intercooling.
4.3. Iphampu yoketshezi
Amaphampu andisa ingcindezi yoketshezi. Kuketshezi olungacindezelwa, ushintsho lwe-enthalpy luvame ukulinganiselwa ngokuthi:
\[
w_p \cishe v \Delta p
\]
lapho i-\(v\) ingumthamo othize (m³/kg) kanye ne-\(\Delta p\) ingukukhuphuka kwengcindezi. Ngenxa yokuthi i-\(v\) incane, umsebenzi wepompo nge-kg uvame ukuba ngaphansi kowe-gas compressor.
Izinzuzo zezimboni: ubukhulu bephampu nenjini, ukuhlaziywa kokulahlekelwa yikhanda, kanye nokuhlolwa kokusetshenziswa kwamandla ohlelweni lwamapayipi.
4.4. Ibhoyila (ibhoyila yomusi)
Ibhoyila idlulisela ukushisa kusuka ekushiseni kuya emanzini ukuze kwakheke umusi. Ukuze kulawulwe ivolumu ngendlela ezinzile ngomsebenzi omncane womgodi (\(\dot{W}\approx 0\)):
\[
\dot{Q}_{in} \approx \dot{m}(h_{out}-h_{in})
\]
Lokhu kubalwa kusiza ekunqumeni ukushisa okudingekayo ukuze kukhiqizwe izinga lokukhiqizwa komusi elinikeziwe. Ngaphezu kwalokho, izidingo zikaphethiloli zingabalwa ngokucabangela ukusebenza kahle kokushisa kanye nenani lama-calories kaphethiloli.
Izinzuzo zezimboni: ukuhlolwa kwamandla ebhoyila, ukuhlela amandla, kanye nokunciphisa kanye nokwenza ngcono umnotho.
4.5. I-Condenser
I-condenser isusa ukushisa emphefumulweni kuze kube yilapho kuqina kube uketshezi. Uma kungabikho msebenzi womgodi:
\[
\dot{Q}_{out} \approx \dot{m}(h_{in}-h_{out})
\]
Usayizi we-\(\dot{Q}_{out}\) unquma isidingo samanzi okupholisa noma umthamo wombhoshongo wokupholisa.
Izinzuzo zezimboni: ukwakheka kwesistimu yokupholisa, ukulawulwa kwezinga lokushisa kwenqubo, kanye nokuqapha ukungcola kuma-heat exchanger.
4.6. Isishintshi sokushisa
Ku-heat exchanger, imifudlana emibili ishintshana ngokushisa, futhi ngokuvamile kucatshangwa ukuthi i-adiabatic maqondana nendawo ezungezile (\(\dot{Q}_{surroundings}\approx 0\)) futhi ayisebenzi:
\[
\dot{m}_h(h_{h,in}-h_{h,out}) = \dot{m}_c(h_{c,out}-h_{c,in})
\]
Lesi sibalo siwuhlobo loMthetho Wokuqala olubaluleke kakhulu ekubaleni imithwalo yokushisa nokuqinisekisa ukusebenza kwemishini ensimini.
5. Ukusetshenziswa Kahle Kwamandla Nokuxilonga Imfucuza
UMthetho Wokuqala awusho ngokuqondile ukuthi umshini muhle kangakanani (lokho kuyindawo yoMthetho Wesibili kanye nomqondo we-entropy), kodwa unamandla kakhulu ku:
- Dala ibhalansi yamandla yazo zonke izingxenye zenqubo.
– Thola ukulahlekelwa ukushisa ngenxa yokushisa okungahambi kahle, ukuvuza komusi, noma ukusha okungenawo umphumela omuhle.
– Ukulinganisa ukusebenza kahle kokushisa kalula, isibonelo:
– Ukusebenza kahle kwebhoyila: amandla awusizo omusi/amakhemikhali kaphethiloli.
– Ukusebenza kahle kwe-turbine-generator: ukunciphisa amandla kagesi / umusi.
– Nquma izinto eziza kuqala ezongiwe: imishini ene-\(\dot{Q}\) noma i-\(\dot{W}\) enkulu kunazo zonke ivame ukuba yinhloso eyinhloko yokwenza ngcono.
Ekuhlolweni kwamandla, onjiniyela baqoqa izinga lokushisa, ingcindezi, izinga lokugeleza, kanye nedatha yamandla kagesi bese behlela yonke imigudu yamandla engenayo nephumayo. Ukungafani kwebhalansi yamandla kuvame ukukhombisa izinkinga zemishini, ukungcola, ukuvuza, noma izibikezelo zokusebenza ezingavumelekile.
6. Isibonelo Esifushane Sendlela Yokucabanga (Ngaphandle Kwezinombolo Eziyinkimbinkimbi)
Ake sithi i-turbine ithola umusi one-enthalpy ephezulu bese ikhipha umusi one-enthalpy ephansi. Uma izinga lomusi laziwa, khona-ke amandla e-turbine alingana kahle ne-\(\dot{m}(h_1-h_2)\). Uma amandla angempela emancane kakhulu, unjiniyela uzohlola amathuba alandelayo:
– ukusebenza kahle kwe-turbine kwehla (umonakalo we-blade, ukuguguleka, ama-deposit),
– ukuvuza komusi kudlule uphawu,
– izimo zokungena aziklanywanga ngendlela ehlelekile (ukwehla kwengcindezi/ukushisa),
– ukuba khona kokudluliselwa kokushisa okungafuneki noma izinguquko ezimweni zokugeleza.
Lonke lolu phenyo luqala eMthethweni Wokuqala: "amandla ayaphi?"
7. Isiphetho
Umthetho Wokuqala We-Thermodynamics uyithuluzi eliyisisekelo kodwa elisetshenziswa kakhulu ekuhlaziyeni imishini yezimboni. Ngokusebenzisa izilinganiso zamandla kuma-turbine, ama-compressor, amaphampu, ama-boiler, ama-condenser, kanye nama-heat exchanger, onjiniyela bangakwazi ukubala ngokuhlelekile izidingo zokushisa, amandla omgodi, umkhiqizo womsebenzi, kanye nemithwalo yokupholisa. Nakuba ukusebenza kahle kwamandla kudinga uMthetho Wesibili, uMthetho Wokuqala uhlala uyindawo yokuqala ebalulekile yokuklama, ukusebenza, kanye nokwenza ngcono amandla kwezitshalo zanamuhla.
Uma ufisa, ngingangeza inguqulo yesihloko ehlanganisa izifundo zezibalo (isb. ukubalwa kwamandla e-turbine/compressor noma izilinganiso zamandla ebhoyila) ngezinyathelo ezinemininingwane kanye namathebula ezakhiwo afanele.
