Molao oa Pele oa Thermodynamics Tlhahlobo ea Mechini ea Liindasteri
Ka mora lerata la diturbine, mocheso wa dionto tsa boiler, le ho duma ha di-compressor difekthering, ho na le molao-motheo o le mong wa motheo o batlang o le teng kamehla: Molao wa Pele wa Thermodynamics. Molao ona ke motheo wa ho utlwisisa hore na matla a tsamaya le ho fetoha jwang ka hara mechini ya diindasteri. Ka ho o tseba hantle, baenjiniere ba ka bala ditlhoko tsa mafura, ba hakanya bokgoni, ba rala ditsamaiso tsa ho phodisa, esita le ho hlahloba tshenyo ya matla disebedisweng tsa tlhahiso. Sengolwa sena se bua ka mehopolo, di-equation tsa bohlokwa, le mehlala ya ditshebediso tsa Molao wa Pele wa Thermodynamics tlhahlobong ya mechini ya diindasteri.
1. Ho utloisisa Molao oa Pele oa Thermodynamics
Molao oa Pele oa Thermodynamics ha e le hantle ke molao oa paballo ea matla. Matla a ke ke a bōptjoa kapa a timetsoa; a ka fetisetsoa feela ho tloha tsamaisong e 'ngoe ho ea ho e 'ngoe kapa a fetoloa ho tloha sebopehong se seng ho ea ho se seng. Moelelong oa thermodynamics, mefuta ea matla eo hangata ho buuoang ka eona ke:
– Mocheso (mocheso, Q): matla a fetisetswang ka lebaka la dipharologanyo tsa mocheso.
– Mosebetsi (W): matla a fetisetswang ka lebaka la matla a bakang ho falla, mohlala, mosebetsi wa shaft hodima turbine kapa compressor.
– Matla a ka hare (U): matla a microscopic ka har'a ntho (e amanang le mocheso, mohato le tšebelisano ea limolek'hule).
– Litlatsetso tsa bohlokoa tsamaisong ea phallo: matla a kinetic (KE) le matla a ka bang teng (PE).
Ka mantsoe a bonolo, Molao oa Pele o re: phetoho ea matla a sistimi e lekana le tlhahiso ea matla ntle le tlhahiso ea matla.
2. Mekhoa ea Thermodynamic Mechining ea Liindasteri
Tlhahlobong ea mechini ea indasteri, hangata re khetha e 'ngoe ea mefuta e 'meli ea litsamaiso:
1. Sistimi e koetsoeng
Boima ha bo tšele meeli ea sistimi, empa matla (mocheso/mosebetsi) a ka fetisoa. Mohlala: silindara-piston lits'ebetsong tse ling tsa sehlopha (mohlala, liteko tsa laboratori kapa lits'ebetso tse khethehileng).
2. Bula sistimi / bophahamo ba modumo ba taolo
Boima le matla li ka tšela meeli. Sena se atile haholo indastering: liturbine, li-compressor, lipompo, liboiler, li-condenser, li-heat exchanger, li-nozzle, li-diffuser le liphaephe.
Bongata ba lisebelisoa tsa tlhahiso li hlahlojoa e le bophahamo ba taolo tlas'a maemo a tsitsitseng, ho bolelang hore sekhahla sa phallo le thepa ea mokelikeli ha li fetohe ha nako e ntse e ea ntlheng efe kapa efe e fanoeng.
3. Tekanyo e Akaretsang ea Molao oa Pele oa Thermodynamics
3.1. Bakeng sa litsamaiso tse koetsoeng
Tekanyo ea motheo:
\[
\Delta E = Q – W
\]
moo \(\Delta E\) e kenyeletsang diphetoho matleng a ka hare, a kinetic, le a bokgoni. Maemong a mangata a sebetsang, diphetoho matleng a kinetic le a bokgoni di hlokomolohuwa hoo:
\[
\Delta U = Q – W
\]
Tlhaloso: ho kena ka mocheso ho eketsa matla a ka hare, ha mosebetsi o etsoang ke sistimi o fokotsa matla a ka hare (ho latela tumellano ea letšoao, empa tumellano e akaretsang ea boenjiniere ke: Ho kena ka Q ho ntle, ho tloha ha W (ho hlahisoang ke sistimi) ho ntle).
3.2. Bakeng sa litsamaiso tse bulehileng (taolo ea molumo)
Bakeng sa phallo e tsitsitseng ea e 'ngoe ho ea ho e 'ngoe, mokhoa o sebelisoang hangata ke:
\[
\dot{Q} – \dot{W} = \dot{m}\left[(h_2-h_1) + \frac{V_2^2 – V_1^2}{2} + g(z_2-z_1)\right]
\]
Lintlha:
– \(\dot{Q}\): sekhahla sa phetisetso ya mocheso (kW)
– \(\dot{W}\): sekhahla sa mosebetsi (kW), hangata ka sebopeho sa mosebetsi wa shaft
– \(\dot{m}\): sekgahla sa phallo ya boima (kg/s)
– \(h\): enthalpy e itseng (kJ/kg)
– \(V\): lebelo la phallo (m/s)
– \(z\): bophahamo (m)
Mechineng e mengata ea indasteri, liphetoho tsa bophahamo le matla a kinetic li nyane haholo ha li bapisoa le phetoho ea enthalpy, kahoo li nolofalitsoe ho:
\[
\dot{Q} – \dot{W} \hoo e ka bang \dot{m}(h_2-h_1)
\]
Ke mofuta ona o bonolo o etsang hore Molao oa Pele o sebetse hantle: ka data ea enthalpy ea ho kena le ho tsoa feela, re ka hakanya litlhoko tsa mocheso kapa matla a shaft.
4. Kopo Mechining ea Liindasteri
4.1. Turbine ea mouoane kapa turbine ea khase
Li-turbine li fetola matla a mocheso a mokelikeli hore e be mosebetsi oa shaft. Bakeng sa turbine ea boemo bo tsitsitseng, hangata ho nahanoa hore ke adiabatic (\(\dot{Q}\approx 0\)):
\[
-\dot{W} \hoo e ka bang \dot{m}(h_2-h_1)
\]
Kaha \(h_2 < h_1\) (enthalpy decrease), joale \(\dot{W}\) e ntle ha e le matla a hlahisoang. Ho tloha mona, matla a turbine a ka baloa haeba sekhahla sa phallo ea boima le phokotso ea enthalpy li tsejoa ho latela litafole tsa mouoane kapa data ea thepa ea khase. Melemo ea indasteri: ho baloa ha tlhahiso ea matla, tlhahlobo ea katleho ea turbine isentropic, le khakanyo ea tšebeliso ea mouoane ka kWh. 4.2. Kompresa ea moea Kompresa e hloka mosebetsi oa shaft ho eketsa khatello e le hore enthalpy e eketsehe (\(h_2>h_1\)). Bakeng sa kompresa ea adiabatic:
\[
\dot{W}_{in} \hoo e ka bang \dot{m}(h_2-h_1)
\]
Sena se bolela hore bongata ba matla a motlakase a hlokahalang ke compressor bo laolwa ke keketseho ea enthalpy, e susumetsoang ke karolelano ea khatello, mocheso oa ho kena le katleho ea khatello.
Melemo ea indasteri: ho fumana litlhaloso tsa enjene, ho bala litšenyehelo tsa matla a khatello, le ho bapisa li-compressor tsa mohato o le mong khahlanong le tsa mekhahlelo e mengata tse nang le intercooling.
4.3. Pompo ea metsi
Lipompo li eketsa khatello ea mokelikeli. Bakeng sa maro a sa hatelleng, phetoho ea enthalpy hangata e hakanngoa ka:
\[
w_p \haufinyane v \Delta p
\]
moo \(v\) e leng bophahamo bo itseng (m³/kg) le \(\Delta p\) e leng keketseho ya kgatello. Hobane \(v\) e nyane, mosebetsi wa pompo ka kg hangata o ka tlase ho wa compressor ya kgase.
Melemo ea indasteri: boholo ba pompo le enjene, tlhahlobo ea tahlehelo ea hlooho, le tlhahlobo ea tšebeliso ea matla a sistimi ea liphaephe.
4.4. Boiler (boiler ea mouoane)
Boiler e fetisetsa mocheso ho tloha mollong ho ea metsing ho etsa mouoane. Bakeng sa taolo ea molumo e tsitsitseng ka mosebetsi o monyane oa shaft (\(\dot{W}\approx 0\)):
\[
\dot{Q}_{in} \approx \dot{m}(h_{out}-h_{in})
\]
Palo ena e thusa ho fumana mocheso o hlokahalang ho hlahisa sekgahla se itseng sa tlhahiso ya mouoane. Ho feta moo, ditlhoko tsa mafura di ka balwa ka ho nahana ka bokgoni ba ho tuka le boleng ba dikhalori tsa mafura.
Melemo ea indasteri: tlhahlobo ea matla a boiler, moralo oa bokhoni, le ho phatloha ha motlakase le ntlafatso ea moruo.
4.5. Sekontiri
Sekontiri se tlosa mocheso ho tloha mouoaneng ho fihlela o fetoha mokelikeli. Haeba ho se na mosebetsi oa shaft:
\[
\dot{Q}_{out} \approx \dot{m}(h_{in}-h_{out})
\]
Boholo ba \(\dot{Q}_{out}\) bo khetholla tlhoko ea metsi a pholileng kapa bokhoni ba tora ea ho pholisa.
Melemo ea indasteri: moralo oa sistimi ea ho pholisa, taolo ea mocheso oa ts'ebetso, le tlhokomelo ea litšila liphapanyetsanong tsa mocheso.
4.6. Sehokelo sa mocheso
Moketjaneng o fapanyetsanang mocheso, melapo e 'meli e fapanyetsana mocheso, 'me hangata ho nkoa hore ke adiabatic mabapi le tikoloho (\(\dot{Q}_{surroundings}\approx 0\)) 'me ha e sebetse:
\[
\dot{m}_h(h_{h,in}-h_{h,out}) = \dot{m}_c(h_{c,out}-h_{c,in})
\]
Tekanyo ena ke mofuta oa Molao oa Pele o bohlokoa haholo bakeng sa ho bala meroalo ea mocheso le ho netefatsa ts'ebetso ea lisebelisoa tšimong.
5. Tlhahlobo ea Tšebeliso e Botle ea Matla le Litšila
Molao oa Pele ha o bolele ka ho toba hore na mochini o motle hakae (ke oona sebaka sa Molao oa Bobeli le khopolo ea entropy), empa o matla haholo bakeng sa:
- Theha tekanyo ea matla bakeng sa li-unit tsohle tsa ts'ebetso.
– Hlalosa tahlehelo ea mocheso ka lebaka la ho se sireletsehe hantle ha mocheso, ho dutla ha mouoane, kapa ho cha ho sa lokelang.
– Ho lekanya bokgoni ba mocheso habonolo, mohlala:
– Bokgoni ba boiler: matla a mouoane a thusang / matla a lik'hemik'hale a mafura.
– Bokgoni ba jenereithara ya turbine: phokotso ya matla a motlakase / mouoane.
– Fumana lintho tsa bohlokoa tse bolokang: lisebelisoa tse nang le \(\dot{Q}\) kapa \(\dot{W}\) tse kholo ka ho fetisisa hangata ke sepheo se seholo sa ntlafatso.
Tlhahlobong ea matla, baenjiniere ba bokella mocheso, khatello, sekhahla sa phallo le data ea matla a motlakase ebe ba etsa 'mapa oa phallo eohle ea matla e kenang le e tsoang. Liphapang tsa tekanyo ea matla hangata li bontša mathata a lisebelisoa, litšila, ho lutla, kapa likhakanyo tse sa sebetseng hantle tsa ts'ebetso.
6. Mohlala o Mokhutšoanyane oa Mokhoa oa ho Nahana (Ntle le Lipalo tse Rarahaneng)
A re re turbine e amohela mouoane o nang le enthalpy e phahameng mme e ntsha mouoane o nang le enthalpy e tlase. Haeba sekgahla sa mouoane se tsebahala, joale matla a turbine a lekana hantle le \(\dot{m}(h_1-h_2)\). Haeba matla a nnete a le manyane haholo, moenjiniere o tla batlisisa menyetla e latelang:
– bokgoni ba turbine boa fokotseha (tshenyo ya lehare, kgoholeho ya mobu, dipolanka),
– ho dutla ha mouoane ho feta sekwahelo,
– maemo a ho kena ha a a etsetswa jwalo ka ha a rerilwe (kgatello/ho theoha ha mocheso),
– boteng ba phetiso e sa batleheng ya mocheso kapa diphetoho maemong a phallo.
Diphuputso tsena kaofela di qala ho tswa Molaong wa Pele: "matla a ya kae?"
7. Qetello
Molao oa Pele oa Thermodynamics ke sesebelisoa sa bohlokoa ka ho fetisisa empa se sebelisoang khafetsa tlhahlobong ea mechini ea indasteri. Ka ho sebelisa litekanyo tsa matla ho li-turbine, li-compressor, lipompo, li-boiler, li-condenser le li-heat exchanger, baenjiniere ba ka bala ka mokhoa o hlophisehileng litlhoko tsa mocheso, matla a shaft, tlhahiso ea mosebetsi le meroalo ea ho pholisa. Leha ts'ebetso ea matla e hloka Molao oa Bobeli, Molao oa Pele e ntse e le ntlha ea bohlokoa ea ho qala bakeng sa moralo, ts'ebetso le ntlafatso ea matla ea limela tsa sejoale-joale.
Haeba o lakatsa, nka eketsa mofuta wa sengoloa o kenyeletsang dithuto tsa dipalo (mohlala, dipalo tsa matla a turbine/compressor kapa ditekanyo tsa matla a boiler) ka mehato e qaqileng le ditafole tsa thepa tse amehang.
