Ua li cas Nto Roughness ntawm lub phaj cua sov cuam tshuam rau hluav taws xob hluav taws xob hloov hluav taws xob thaum kub kub?

Tshaj 300℃ib lub phaj cua sov hloov lub zog ntau tsis yog los ntawm kev kov tab sis los ntawm qhov pom tsis pom hluav taws xob hluav taws xob. Lub pob khawm tswj kom zoo npaum li cas nws radiates yog seb lub ntsej muag ntawm lub phaj yog ci thiab polished los yog npub thiab ntxhib. Qhov no yog qhov tshwj xeeb tshaj yog nyob rau hauv lub tshuab nqus tsev, tsis kov cov cua sov thiab kub kub ua haujlwm qhov twg convection txwv.

Radiation raws li lub hom phiaj tseem ceeb ntawm Kev Hloov Kub Kub
Ntawm qhov kub siab thermal hluav taws xob yog qhov tseem ceeb ntawm kev hloov hluav taws xob tag nrho. Nyob rau hauv cov kev tswj hwm no, qhov ua tau zoo ntawm cov hluav taws xob hluav taws xob hloov hluav taws xob hluav taws xob tsawg tsawg yog txiav txim siab los ntawm cov khoom siv zoo ntawm qhov roughness ntawm qhov chaw thiab txiav txim siab ntau dua los ntawm kev sib cuam tshuam ntawm qhov chaw nrog infrared wavelengths.

Radiative efficiency yog xam los ntawm emissivity, uas yog ib qho kev ntsuas ntawm npaum li cas ib tug nto radiates thermal zog txheeb ze rau ib tug zoo tagnrho blackbody.

Emissivity Effects: Polished Versus Rough Surfaces
Cov hlau du nto qhia txog lub zog infrared zoo li daim iav. Feem ntau ntawm cov teeb meem hluav taws xob yog reflected, tsis absorbed los yog emitted. Yog li, emissivity nyob qis qis.

Ntawm qhov tod tes, qhov roughened nto qhia txog micro- nplai qhov thiab qhov tsis zoo. Cov yam ntxwv no txwv cov hluav taws xob los ntawm kev rov qab los ntawm sab hauv, thiab ua kom muaj txiaj ntsig zoo ntawm kev nqus thiab rov ua dua - emission.

Qhov tseeb:

Emissivity ntawm polished aluminium phaj tuaj yeem qis li ~0.05 .

Feem ntau, oxidized los yog maj mam roughened txhuas nto yog nyob rau hauv qhov ntau ntawm 0.2-0.3

Cov chaw roughened heev, xws li grit- blasted nto, tuaj yeem txhim kho qhov ua tau zoo

Dab tsi zoo li ci rau lub qhov muag kuj ci rau cov hluav taws xob infrared, thiab dab tsi zoo li npub radiates zoo, thiab. Ib tug roughened nto feem ntau roughly quadruple radiative tshav kub hloov mus rau ib tug polished sib npaug nyob rau hauv tib yam mob.

Emissivity raws li Thermal Design Parameter
Feem ntau cov emissivity yog hu ua thermal xim ntawm ib tug nto. Nws yog ib qho kev ntsuas ntawm kev koom tes ntawm cov khoom siv hluav taws xob sib pauv, tsis yog xim pom.

Qee yam yuav tsum nco ntsoov:

Emissivity dependence ntawm kub thiab wavelength

Qhov saum npoo oxidation tuaj yeem hloov pauv hluav taws xob ua haujlwm tau zoo nyob rau lub sijhawm

Qhov ntsuas emissivity tsis nyob ntawm cov yam ntxwv zoo li Ra, thiab xav tau cov cuab yeej tshwj xeeb.

Rau cov tshuab kub kub, emissivity tseem ceeb npaum li cov conductivity thaum nws los txog rau tag nrho cov cua kub tus cwj pwm.

Cov nyhuv ntawm Kev Kho Nto thiab Txheej
Kev coj tus cwj pwm hluav taws xob tuaj yeem ua tiav los ntawm cov txheej txheej saum npoo tsis hais qhov ua tiav ntawm lub hauv paus substrate.

PTFE txheej feem ntau muaj emissivities ntawm qhov kev txiav txim ntawm ~ 0.9.

Ceramic txheej feem ntau ncav cuag 0.8

Cov txiaj ntsig zoo sib xws ntawm ntau yam hauv paus hlau tiav

Nyob rau hauv cov ntaub ntawv ntawm kev siv lub coated cua sov phaj, qhov xwm txheej ntawm lub txheej muaj peev xwm kov yeej lub zog ntawm lub substrate roughness.

Tab sis rau cov hlau liab qab, kev kho tshuab saum npoo tseem yog ib txoj hauv kev los kho cov hluav taws xob ua haujlwm.

Qhov cuam tshuam rau cua sov Efficiency thiab txheej txheem tsim
Cov emissivity siab dua tam sim ntawd ua rau muaj kev hloov pauv hluav taws xob hauv lub tshuab nqus tsev, cov cua sov infrared thiab tsis yog - tiv tauj cov ntawv thov thermal. Ib qho rougher saum npoo yuav ua rau kom muaj hluav taws xob sib txuas ntxiv rau cov khoom thauj, ua rau cov cua sov sai dua.

Tab sis tej zaum yuav muaj kev lag luam - tawm xws li:

Nce rhiab heev rau oxidation ntawm siab kub

Emissivity fluctuation muaj peev xwm ntawm lub neej ua haujlwm ntev

Lower reflectance nyob rau hauv daim ntawv thov uas muaj kev tswj hluav taws xob shielding

Cov ntsiab lus
Nto roughness tswj muab ib qho yooj yim passive txoj kev los kho tus cwj pwm ntawm radiative tshav kub hloov nyob rau hauv cov cua kub daim hlau, tshwj xeeb tshaj yog nyob rau hauv high kub thaum hluav taws xob dominates. Ib tug roughened nto tsub kom lub emissivity thiab tsub kom lub efficiency ntawm lub zog hloov. Polished nto cuam tshuam rau qis radiative tso zis.

Txhua qhov chaw muaj nws tus kheej thermal cwm pwm, ua haujlwm ntawm nws cov emissivity, thiab qhov no dhau los ua tus qauv tsim qauv tseem ceeb hauv kev kub siab thermal engineering systems.