Ucwaningo Lokushisa Kwezinjini Zokushisa Okuphezulu
Imishini eshisa kakhulu—njengezitofu zezimboni, ama-boiler, ama-gas turbine, ama-cement kiln, ama-chemical reactor, kanye nezinjini ze-jet—isebenza ngaphansi kwezimo ezishisayo kakhulu ezidinga ukuphathwa kokushisa okucophelelayo. Phakathi kwezindlela ezintathu zokudlulisa ukushisa (ukuqhuba, ukudlulisa ukushisa, kanye nemisebe), imisebe eshisayo ivame ukuba yingxenye evelele lapho amazinga okushisa angaphezulu enyuka kakhulu. Lesi sihloko sixoxa ngemiqondo eyisisekelo yemisebe, izindlela zokufunda nokulinganisa, ukumodela, kanye nemiphumela yayo ekwakhiweni nasekuphepheni kwemishini eshisa kakhulu.
1. Kungani ukushisa kwemisebe kubalulekile emazingeni okushisa aphezulu?
Imisebe yokushisa iwukudluliselwa kwamandla ngendlela yamagagasi kagesi, ikakhulukazi ku-spectrum ye-infrared, emazingeni okushisa okusebenza kwemishini yezimboni . Ngokungafani nokuqhuba kanye nokushintshashintsha, okudinga indawo ephakathi (eqinile noma ewuketshezi), imisebe ingenzeka ngisho nange-vacuum. Emishinini eshisa kakhulu, umnikelo wemisebe uyanda ngokushesha ngoba ubukhulu bayo bulandela umthetho wamandla wesine maqondana nokushisa okuphelele (i-Kelvin). Lokhu kusho ukuthi ukwanda kwezinga lokushisa kusuka ku-800 K kuya ku-1000 K kungakhuphula kakhulu ukugeleza kwemisebe, ngisho nalapho ezinye izilinganiso zihlala zingaguquguquki.
Umthelela osebenzayo mkhulu: imisebe yokushisa ithinta ukusebenza kahle kokushisa , impilo yezinto ezibonakalayo, ukuzinza kokusebenza, ikhwalithi yomkhiqizo ezinqubweni zokushisa (isb. ukushisa kwezinto ezibonakalayo), kanye nezici zokuphepha njengengozi yomlilo kanye nokuchayeka ekushiseni kubasebenzi noma izingxenye ezibucayi.
2. Isisekelo semfundiso: Umthetho kaStefan–Boltzmann kanye nokukhishwa kwempahla
Ukuze kube nobuso obuhle “bomzimba omnyama” obumunca futhi bukhiphe imisebe ngokuphelele, ukukhishwa kwemisebe endaweni ngayinye kwakhiwa uMthetho kaStefan-Boltzmann:
\[
q = \sigma T^4
\]
no:
– \(q\) = uketshezi lwemisebe (W/m²)
– \(\sigma\) = Stefan–Boltzmann njalo (≈ \(5{,}67 \izikhathi 10^{-8}\) W/m²·K⁴)
– \(T\) = izinga lokushisa eliphelele lobuso (K)
Noma kunjalo, izindawo zangempela azizona imizimba emnyama. Ngakho-ke, kusetshenziswa i-emissivity (\(\varepsilon\)), enenani elingu-0–1. Ezindaweni zangempela:
\[
q = \varepsilon \sigma T^4
\]
Ukukhishwa kwegesi kuthinteka yizinto ezibonakalayo, ubulukhuni bomphezulu, ukushiswa kwegesi, ukumbozwa, kanye nobude bemisebe. Ezinjinini ezishisa kakhulu, izindawo zensimbi zivame ukuba ne-oxidation, okungakhulisa ukushiswa kwegesi, ngaleyo ndlela kwandise imisebe ephumayo. Lokhu kungaba wusizo ekupholiseni okungenamsebenzi, kodwa kube yingozi uma umgomo wesistimu ukugcina ukushisa ngaphakathi kwegumbi lokushisa noma esithandweni somlilo.
3. Ukushintshana kwemisebe phakathi kobuso: isici sokubuka
Eqinisweni, okubalulekile akukhona nje kuphela imisebe ekhishwayo, kodwa imisebe ehlanzekile edlula isuka kwenye indawo iye kwenye. Inani lincike ku:
– izinga lokushisa lobuso ngabunye,
- ukukhishwa kwegesi,
– i-geometry kanye nokuma kobuso,
– kanye nesici sokubuka, okuyingxenyana yemisebe evela endaweni eyodwa efinyelela kwenye indawo.
Isibonelo, ekamelweni lokushisa le-turbine yegesi noma esithandweni somlilo, izindonga, isishisi, kanye nento yokushisa konke "kuyabonana". Isici sokubuka sisiza ekubaleni ukuthi ukushisa kugeleza kakhulu ezindongeni, kumthwalo (izinto ezifudumayo), noma kulahleka ngezimbobo.
4. Imisebe emagesini ashisayo nasezinhlayiyeni
Ezinjinini ezishisa kakhulu, indawo ephakathi kwezindawo ngokuvamile akuyona umoya ohlanzekile, kodwa amagesi okushisa (i-CO₂, umhwamuko we-H₂O), umusi, noma izinhlayiya zomshoshaphansi. Amagesi athile anesimo "sokukhipha nokumunca" imisebe kuma-wavelength athile. Lesi simo sibalulekile ku:
– ama-boilers kanye nezitofu zokushisa,
- umshini wokushisa,
– igumbi lokushisa i-turbine yegesi,
– i-reactor yokushisa okuphezulu.
Izinhlayiya, njenge-soot nomlotha, zingandisa ukukhishwa kanye nokumuncwa kwemisebe, ngokuvamile zandise ukudluliselwa kokushisa okukhanyayo ezindongeni. Ngakho-ke, izifundo zemisebe ezinjinini ezishisa kakhulu azikwazi nje ukucabanga ngezindawo eziqinile, kodwa futhi kufanele zicabangele nendawo ebambe iqhaza.
5. Indlela yokulinganisa imisebe yokushisa
Izifundo zemisebe yokushisa zidinga idatha ngezinga lokushisa, izakhiwo zomphezulu, kanye nama-spectra emisebe. Ezinye izindlela ezivamile zifaka:
1. I-infrared pyrometer (i-IR pyrometer)
Kusetshenziswa ukukala izinga lokushisa lobuso ngaphandle kokuthintana. Inselele ukuthola ukuthi i-emissivity ifanele; amaphutha eku-emissivity angaholela emaphutheni amakhulu okushisa.
2. Ikhamera yokushisa (isithombe sokushisa)
Kuwusizo ekuhleleni ukusatshalaliswa kwezinga lokushisa kanye nezindawo ezishisayo. Kufanelekile ukuhlola izitofu, ukufudumala, noma izingxenye ze-turbine. Kodwa-ke, ukuhumusha kusaxhomeke ekukhipheni ugesi kanye nomthelela wokukhanya okuvela emvelweni.
3. Inzwa yokushintsha kokushisa / i-radiometer
Ilinganisa ukugeleza kokushisa okutholwa yinzwa. Ingasetshenziswa ukuhlola umthwalo wemisebe ezingxenyeni ezithile, njengezivikelo zokushisa noma ama-casing.
4. I-Spectrometry kanye ukuhlaziywa kwegesi
Kwimidiya yegesi yokushisa, ukuhlaziywa kwe-spectrum kusiza ukulingisa umnikelo we-CO₂ kanye ne-H₂O emisebeni, ikakhulukazi ngaphansi kwengcindezi kanye izinga lokushisa eliphezulu.
Ukulinganisa insimu kuvame ukuhlanganisa amathuluzi amaningana ukwenza imiphumela ibe nembayo kakhudlwana: isibonelo, ikhamera yokushisa yamamephu, i-pyrometer yokuqinisekisa iphuzu, kanye nenzwa yokushintshashintsha kokushisa ukuqinisekisa ukudluliselwa kokushisa.
6. Ukumodela nokulingisa: kusukela ekubaleni okulula kuya ku-CFD
Izindlela zokutadisha imisebe yokushisa ngokuvamile zihlukaniswe kanje:
- Imodeli elula yokuhlaziya
Ifanelekela ukulinganisa kokuqala, isibonelo, ukubala ukulahleka kokushisa okukhanyayo kusuka ebusweni bangaphandle bepayipi lokushisa noma isikhwama senjini. Lo modeli uyashesha, kodwa ngokuvamile udinga ukucabanga ngokukhishwa okuqhubekayo kanye ne-geometry elula.
- Indlela yezinombolo yokushintshana kwemisebe ebusweni
Ukusebenzisa indlela ye-view factor kanye ne-radiosity ukuze ukubala ukushintshaniswa kwamandla phakathi kwezindawo ezivalekile, njengesithando esimise okwebhokisi noma esiyisilinda.
– I-CFD enemodeli yemisebe
Ezinhlelweni eziyinkimbinkimbi ezinokugeleza kwegesi yokushisa kanye Uma kuziwa ekuphenduleni kwamakhemikhali, i-CFD ivame ukusetshenziswa. Amamodeli emisebe afana ne-P1, i-Discrete Ordinates (DO), noma i-Monte Carlo asiza ekuphatheni imithombo ehlanganyelayo. Nakuba enembile kakhulu, i-CFD idinga idatha ngezakhiwo zemisebe yegesi kanye nezinhlayiya kanye nomzamo owengeziwe wokubala.
Ukuqinisekiswa kubalulekile: imiphumela yokulingisa kumele iqhathaniswe nedatha elinganisiwe ukuqinisekisa ukuthi amapharamitha anjengokukhishwa okuphumelelayo, ukusatshalaliswa kwe-soot, noma i-gas absorption coefficient awaphambuki.
7. Imiphumela yomklamo: izinto zokwakha, ukumbozwa, kanye nokufakwa kokushisa
Izifundo zemisebe yokushisa zinomthelela oqondile ezinqumweni zokuklama:
- Ukukhetha izinto kanye nemikhawulo yokushisa
Izinto ezifana nama-superalloy, ama-ceramics, kanye nezinhlanganisela ziyasetshenziswa ngoba ziyamelana nokuqhekeka kanye nokushiswa kwegesi emazingeni okushisa aphezulu. Kodwa-ke, imithwalo yemisebe ingadala amazinga okushisa aphezulu angabangela ukuqhekeka kokushisa.
– Ukugqoka kwesithiyo sokushisa (TBC)
I-TBC kuma-turbine egesi ukunciphisa izinga lokudluliselwa kokushisa ku-substrate yensimbi. Ngaphezu kokuqhuba okuphansi komoya, ukukhishwa kwengubo nakho kuthinta ibhalansi yamandla akhanyayo.
– Ukuvikela kanye nolwelwesi oluqinile
Ezithandweni, izinto ezivimbela ukushisa zinciphisa ukulahleka kokushisa esakhiweni sangaphandle. Izindawo ezivimbela ukushisa zivame ukuba nomswakama ophezulu; lokhu kungasiza ekushiseni okukhanyayo kweshaja, kuthuthukise ukufana kokushisa, kodwa kumele kulinganiswe nokulawula ukulahleka kokushisa ngokusebenzisa izimbobo.
- Ukuphathwa "kwezindawo ezishisayo"
Ukusatshalaliswa kwemisebe okungalingani kungadala izindawo ezishisayo ezindongeni noma ezingxenyeni. Ukwakheka kwe-geometric, indawo yokushisa, kanye nokusetshenziswa kwama-baffle/reflector ngezinye izikhathi kusetshenziswa ukulinganisa umthwalo wemisebe.
8. Ukuphepha nokuthembeka
Imisebe yokushisa nayo iyinkinga yokuphepha. Ukuchayeka emisebeni ephezulu kungaba yingozi kubasebenzi, kulimaze izintambo/izinsimbi, noma kubangele ukuwohloka kwezithambisi kanye nezivalo. Ngakho-ke, imboni isebenzisa:
– isivikelo sokushisa (isivikelo sokushisa),
- ibanga eliphephile kanye nokuvikela uthuli,
- izinqubo zokuhlola i-thermographic ngezikhathi ezithile,
– kanye nesistimu yokukhiya uma kutholwa izinga lokushisa elingaphezulu.
Ngasohlangothini lokuthembeka, imisebe ephezulu isheshisa i-oxidation, ithinta izakhiwo zemishini, futhi isheshise ukukhathala kokushisa. Izifundo zemisebe yokushisa zisiza ukubikezela impilo yezingxenye nokuthuthukisa amashejuli okugcinwa asekelwe ezimweni.
9. Isiphetho
Imisebe yokushisa iyindlela evelele kakhulu yokudlulisa ukushisa ezinjinini ezishisa kakhulu ngoba incike kakhulu ekushiseni (kumandla wesine). Ukuqonda ukukhishwa kwegesi, isici sokubuka, kanye nendima yamagesi okushisa kanye nezinhlayiya kwakha isisekelo sezifundo ezinembile. Ukulinganisa kusetshenziswa ama-pyrometer, amakhamera okushisa, kanye nezinzwa ze-flux kuhambisana nomodeli wokuhlaziya, i-radiosity, kanye ne-CFD ukubikezela imithwalo yokushisa kanye nokunciphisa umklamo. Ngezifundo zokukhishwa kwegesi yomsindo, izimboni zingathuthukisa ukusebenza kahle , zilondoloze ukuphepha, futhi zandise impilo yezingxenye zenjini ngaphansi kwezimo zokusebenza ezimbi kakhulu.
Uma ufisa, ngingavumelanisa lesi sihloko nomongo womshini othize (isb., i-turbine yegesi, i-boiler yesitshalo samandla esinomusi, isithando sokuncibilikisa, noma i-oven), kugcwele izibonelo ezilula zokubala kanye nohlu lwezincwadi.
