Chidzidzo cheMwaranzi yeKupisa muInjini dzeKupisa Kwakanyanya
Michina inodziya zvakanyanya—yakadai semaovheni emaindasitiri, mabhoyila, maturbine egasi, makiln esimende, ma reactor emakemikari, uye mainjini ejeti—inoshanda mumamiriro ekunze anopisa zvakanyanya anoda kutarisirwa kwekupisa kwakanyatsonaka. Pakati penzira nhatu dzekufambisa kupisa (conduction, convection, uye radiation), mwaranzi yekupisa inowanzova chinhu chikuru kana tembiricha yepamusoro yakakwira zvakanyanya. Chinyorwa chino chinokurukura pfungwa huru dzemwaranzi, nzira dzekudzidza uye dzekuyera, modelling, uye zvadzinoreva pakugadzira nekuchengetedzeka kwemichina inodziya zvakanyanya.
1. Sei mwaranzi yekupisa ichikosha pakupisa kwakanyanya?
Mwaranzi inopisa ndiyo nzira yekufambisa simba muchimiro chemafungu emagetsi, kunyanya mu infrared spectrum, pakupisa kwekushanda kwemichina yeindasitiri . Kusiyana ne conduction ne convection, izvo zvinoda nzira yepakati (yakasimba kana yemvura), mwaranzi inogona kuitika kunyangwe kuburikidza ne vacuum. Mumichina inodziya zvakanyanya, mupiro wemwaranzi unowedzera nekukurumidza nekuti hukuru hwayo hunotevera mutemo wechina wesimba maererano nekupisa kwakakwana (Kelvin). Izvi zvinoreva kuti kuwedzera kwekushisa kubva pa800 K kusvika 1000 K kunogona kuwedzera zvakanyanya flux yemwaranzi, kunyangwe kana zvimwe zviyero zvichiramba zvakafanana.
Kushanda kwayo kwakakura: mwaranzi yekupisa inokanganisa kushanda zvakanaka kwekupisa , hupenyu hwezvinhu, kugadzikana kwekushanda, mhando yechigadzirwa mukushanda kwekupisa (semuenzaniso kupisa kwezvinhu), pamwe nekuchengetedza kwakadai senjodzi yemoto uye kupisa kuvashandi kana zvinhu zvinonzwa.
2. Hwaro hwedzidziso: Mutemo waStefan–Boltzmann uye kuburitswa kwemafuta
Kuti pave ne "muviri mutema" wakanaka unonyudza uye unoburitsa mwaranzi zvakakwana, kuburitswa kwemwaranzi panzvimbo imwe neimwe kwakagadzirwa nemutemo waStefan-Boltzmann:
\[
q = \sigma T^4
\]
ne:
– \(q\) = kuyerera kwemwaranzi (W/m²)
– \(\sigma\) = Stefan–Boltzmann nguva dzose (≈ \(5{,}67 \kawa 10^{-8}\) W/m²·K⁴)
– \(T\) = tembiricha yepamusoro (K)
Zvisinei, nzvimbo chaidzo hadzisi nhema. Saka, chinhu chinonzi emissivity (\(\varepsilon\)) chinoshandiswa, chine kukosha kwe0–1. Kune nzvimbo chaidzo:
\[
q = \varepsilon \sigma T^4
\]
Kubuda kwemhepo kunokonzerwa nezvinhu, kuomarara kwenzvimbo, kuoxidation, coating, uye radiation wavelength. Mumainjini anodziya zvakanyanya, simbi dzinogara dzichioxidation, izvo zvinogona kuwedzera kubudiswa kwemhepo, nokudaro zvichiwedzera mwaranzi inobuda. Izvi zvinogona kubatsira pakutonhodza kusingapindiki, asi zvinokuvadza kana chinangwa chesystem chiri chekuchengetedza kupisa mukati mekamuri rinopisa kana muchoto.
3. Kuchinjana kwemwaranzi pakati penzvimbo: view factor
Muchokwadi, chinonyanya kukosha haisi mwaranzi inoburitswa chete, asi mwaranzi chaiyo inopfuura kubva pane imwe nzvimbo ichienda kune imwe. Huwandu hwayo hunoenderana ne:
- tembiricha yenzvimbo imwe neimwe,
- kuburitsa zvinhu,
- geometry uye kutarisa pamusoro,
- uye view factor, inova chikamu chemwaranzi inobva pane imwe nzvimbo inosvika pane imwe nzvimbo.
Semuenzaniso, mukamuri rinopisa turbine yegesi kana muchoto, madziro, chitofu, nechinhu chinodziya zvese "zvinoonana". Chinhu chinobatsira kuona kana kupisa kuchiyerera zvakanyanya kumadziro, kumutoro (chinhu chinodziya), kana kuti kunorasika kuburikidza nemaburi.
4. Mwaranzi mumagasi anopisa uye zvidimbu
Mumainjini anodziya zvakanyanya, nzvimbo iri pakati penzvimbo kazhinji haisi mhepo yakachena, asi magasi anobvira (CO₂, H₂O vapor), utsi, kana soot particles. Mamwe magasi ane hunhu hwe "kuburitsa nekutora" mwaranzi pamagetsi chaiwo. Chiitiko ichi chakakosha mu:
- mabhoyira nemidziyo yekupisa,
- chinhu chinopisira moto,
- imba yekupisa turbine yegesi,
– reactor inodziya zvakanyanya.
Zvidimbu zvakaita sedota nemadota, zvinogona kuwedzera kuburitswa nekutorwa kwemwaranzi, zvichiwedzera kutamiswa kwekupisa kumadziro. Saka, zvidzidzo zvemwaranzi mumainjini ane tembiricha yepamusoro hazvingofungi nezvenzvimbo dzakasimba chete, asi zvinofanirawo kufunga nezvenzvimbo inobatanidzwa.
5. Nzira yekuyera mwaranzi yekupisa
Zvidzidzo zvemwaranzi yekupisa zvinoda ruzivo pamusoro pekupisa, hunhu hwepamusoro, uye maspectra emwaranzi. Dzimwe nzira dzakajairika dzinosanganisira:
1. Infrared pyrometer (IR pyrometer)
Inoshandiswa kuyera tembiricha yepamusoro pasina kubata. Dambudziko nderekuona kuti emissivity chaiyo ndeipi; zvikanganiso pakuburitsa emissivity zvinogona kukonzera zvikanganiso zvakakura patembiricha.
2. Kamera yekupisa (mufananidzo wekupisa)
Inobatsira pakuongorora kugoverwa kwetembiricha nenzvimbo dzinopisa. Yakakodzera kuongorora maovheni, thermal insulation, kana zvikamu zveturbine. Zvisinei, kududzirwa kuchiri kuenderana ne emissivity uye simba remwaranzi inoonekwa kubva munharaunda.
3. Sensor yekupisa / radiometer
Inoyera kupisa kunogamuchirwa nesensa. Inogona kushandiswa kuongorora mutoro wemwaranzi pane zvimwe zvikamu, zvakaita sezvidziviriro zvekupisa kana macasing.
4. Spectrometry uye kuongorora gasi
Panyaya yekupisa gasi, ongororo yespectrum inobatsira kuratidza mupiro weCO₂ neH₂O mumwaranzi, kunyanya pasi pekumanikidzwa uye tembiricha yakakwira.
Kuyerwa kwemunda kunowanzo sanganisa maturusi akati wandei kuti mhedzisiro ive yakarurama: semuenzaniso, kamera yekupisa yemamepu, pyrometer yekusimbisa mapoinzi, uye sensor yeflux yekusimbisa kutamiswa kwekupisa.
6. Kugadzira uye kuenzanisa: kubva pakuverenga kuri nyore kusvika kuCFD
Nzira dzekudzidza kupisa kwemwaranzi dzinowanzo patsanurwa kuita:
- Muenzaniso wekuongorora uri nyore
Yakakodzera kufungidzira kwekutanga, semuenzaniso, kuverenga kurasikirwa nekupisa kunobva pamusoro pepombi yekupisa kana keji yeinjini. Modhi iyi inokurumidza, asi kazhinji inoda kufungidzira kwesimba rinogara riripo uye jiometri iri nyore.
- Nzira yenhamba yekuchinjana kwemwaranzi pamusoro
Kushandisa nzira yekuona zvinhu (view factor) uye radiosity (nzira yekuona zvinhu) kuverenga kuchinjana kwesimba pakati penzvimbo dziri munzvimbo yakavharwa, senge chitofu chakaita sebhokisi kana kuti chakaita secylindrical.
- CFD ine muenzaniso wemwaranzi
Munzvimbo dzakaoma dzine magasi anoyerera uye Pakuita kwemakemikari, CFD ndiyo inowanzo shandiswa. Mamodheru emwaranzi akadai seP1, Discrete Ordinates (DO), kana Monte Carlo anobatsira kubata nzira dzekushandisa pamwe chete. Kunyange zvazvo zviri nyore, CFD inoda ruzivo nezvehunhu hwemwaranzi yegasi nezvidimbu uye kushanda nesimba pakuverenga.
Kusimbiswa kwakakosha: mhedzisiro yekufananidzira inofanira kuenzaniswa nedata rakayerwa kuti ive nechokwadi chekuti maparamita akadai se emissivity inoshanda, soot distribution, kana gas absorption coefficient haatsauke.
7. Zvinorehwa nedhizaini: zvinhu, machira, uye kuputira
Zvidzidzo zvemwaranzi yekupisa zvine simba rakananga pakusarudza kwekugadzira:
- Kusarudzwa kwezvinhu uye miganhu yekupisa
Zvinhu zvakaita sema superalloys, ceramics, uye composites zvinoshandiswa nekuti zvinodzivisa kukambaira uye oxidation pakupisa kwakanyanya. Zvisinei, kuwanda kwemwaranzi kunogona kugadzira kupisa kwakanyanya kunogona kukonzera kupwanyika kwekupisa.
– Kuvhara kwekudzivirira kupisa (TBC)
TBC pamaturbine egasi kuderedza mwero wekupfuudzwa kwekupisa kuenda kusimbi. Pamusoro pekufambiswa kwemhepo kwakaderera, kuburitswa kwechinhu ichi kunokanganisawo kuenzana kwesimba rinopenya.
- Kudzivirira kupisa uye jira risingapindi mvura
Mumaovheni, zvinoramba kupisa zvinoderedza kurasikirwa nekupisa kune chimiro chekunze. Nzvimbo dzinoramba kupisa dzinowanzova nekupisa kwakanyanya; izvi zvinogona kubatsira mukupisa kwakajeka kwechaji, zvichivandudza kufanana kwekupisa, asi zvinofanirwa kuenzaniswa nekudzora kurasikirwa nekupisa kuburikidza nemaburi.
- Kutarisira "nzvimbo dzinopisa"
Kupararira kwemwaranzi isina kuenzana kunogona kukonzera nzvimbo dzinopisa pamadziro kana zvikamu. Dhizaini yejometri, nzvimbo yekupisa, uye kushandiswa kwemabaffle/reflectors dzimwe nguva zvinoshandiswa kuenzana kwemwaranzi.
8. Kuchengetedzeka uye kuvimbika
Mwaranzi yekupisa inyayawo yekuchengetedzwa. Kushandiswa kwemwaranzi yakawanda kunogona kukonzera njodzi kuvashandi, kukuvadza tambo/zvishandiso, kana kukonzera kuora kwemafuta nezvisimbiso. Saka, indasitiri iyi inoshandisa:
- chinodzivirira kupisa (chinodzivirira kupisa),
- daro rakachengeteka uye kudzivirira kupisa,
- maitiro ekuongorora thermographic nguva nenguva,
- uye sisitimu yekukiya kana tembiricha yakawandisa yaonekwa.
Panyaya yekuvimbika, mwaranzi yakawanda inokurumidza oxidation, inokanganisa hunhu hwemakanika, uye inokurumidza kuneta kwekupisa. Zvidzidzo zvemwaranzi yekupisa zvinobatsira kufanotaura hupenyu hwechikamu uye kugadzira hurongwa hwekuchengetedza hunoenderana nemamiriro ezvinhu.
9. Kesimpulan
Mwaranzi yekupisa inzira inonyanya kushandiswa mukufambisa kupisa mumainjini ane tembiricha yepamusoro nekuti inoenderana zvakanyanya netembiricha (kune simba rechina). Kunzwisisa emissivity, view factor, uye basa remagasi ekupisa nezvidimbu zvinoumba hwaro hwezvidzidzo zvakarurama. Kuyera uchishandisa mapyrometer, makamera ekupisa, uye ma flux sensors kunowedzera analytical modeling, radiosity, uye CFD kufanotaura mitoro yekupisa uye kuderedza dhizaini. Nezvidzidzo zvemwaranzi yeruzha, maindasitiri anogona kuvandudza kushanda zvakanaka , kuchengetedza kuchengetedzeka, uye kuwedzera hupenyu hwezvikamu zveinjini mumamiriro ekushanda akaipisisa.
Kana muchida, ndinogona kugadzirisa chinyorwa ichi kuti chienderane nemamiriro ezvinhu emuchina chaiwo (semuenzaniso, turbine yegesi, boiler yesimba remhepo, chitofu chekunyungudutsa, kana chitofu), pamwe chete nemienzaniso iri nyore yekuverenga uye bibliography.
