Kev tsom xam ntawm Emissivity ntawm Infrared Thermometers Siv Wuxi Slosen Txoj Cai
Emissivity yog qhov piv ntawm hluav taws xob hluav taws xob ntawm ib yam khoom tiag tiag thiab lub cev dub ntawm tib qhov kub thiab txias hauv tib lub sijhawm. Cov xwm txheej zoo ib yam yog hais txog tib lub geometric tej yam kev mob (emission radiation area, solid angle size and direction for Measuring radiation power) thiab spectral conditions (spectral range for Measuring radiation flux). Vim muaj kev sib raug zoo ntawm emissivity thiab ntsuas, muaj ntau lub ntsiab lus ntawm emissivity.
Hemisphere emissivity Hemisphere emissivity yog qhov piv ntawm radiant zog flux (radiance) emitted los ntawm lub radiator mus rau hauv hemispherical qhov chaw nyob rau hauv ib cheeb tsam rau lub radiance ntawm ib tug blackbody nyob rau tib lub kub, uas yog ntxiv muab faib ua tag nrho thiab spectral ntau.
Ib txwm emissivity
Ib txwm emissivity yog cov emissivity ntsuas nyob rau hauv ib tug me me lub kaum sab xis nyob rau hauv ib txwm kev taw qhia ntawm hluav taws xob nto. Nws yog qhov piv ntawm cov hluav taws xob ci ntsa iab nyob rau hauv cov kev taw qhia ib txwm rau cov hluav taws xob ci ci ntawm lub cev dub ntawm tib qhov kub. Vim lub fact tias infrared systems ntes hluav taws xob hluav taws xob nyob rau hauv ib tug me me lub kaum sab xis nyob rau hauv ib txwm kev taw qhia ntawm lub hom phiaj nto, lub emissivity ib txwm tseem ceeb heev.
Rau blackbody, tag nrho cov emissivities sib npaug li 1, thaum rau cov khoom tiag, qhov tseem ceeb ntawm tag nrho cov emissivities tsawg dua 1. Qhov emissivity peb tam sim no xa mus yog qhov nruab nrab emissivity.
Hais txog emissivity kho:
Qhov emissivity ntawm cov khoom sib txawv ntawm qhov sib txawv, thiab txhawm rau kom ntseeg tau qhov tseeb ntawm qhov ntsuas kub, feem ntau yuav tsum tau kho emissivity. Vim lub fact tias tus pas ntsuas kub yog calibrated nyob rau hauv blackbody, lub nto emissivity ntawm tej yam khoom yog qis dua cov blackbody.
Txoj kev kho cov emissivity ntawm tus pas ntsuas kub infrared yog los kho qhov ua kom muaj zog ntawm lub tshuab hluav taws xob raws li qhov emissivity ntawm cov khoom sib txawv, kom cov teeb liab tsim los ntawm hluav taws xob ntawm cov khoom tiag tiag nrog qee qhov kub hauv qhov system yog tib yam. lub teeb liab generated los ntawm ib tug blackbody nrog tib kub. Piv txwv li, yog tias qhov emissivity ntawm ib yam khoom yog {{0}}.8, nws yog ib qho tsim nyog yuav tsum tau ua kom lub suab nrov ntawm lub tshuab hluav taws xob mus rau qhov qub 1/0.8=1.25 zaug. Txawm li cas los xij, hauv cov chaw lag luam, feem ntau nyuaj rau kev txiav txim siab lub hom phiaj emissivity tsis vim muaj cov khoom sib txawv, cov duab, thiab qhov chaw ntawm lub hom phiaj ntsuas. Kev ntsuas yuam kev tshwm sim los ntawm lwm yam tuaj yeem ua rau muaj qhov sib txawv ntawm qhov ntsuas qhov ntsuas thiab qhov tseeb. Kev taw qhia ntawm emissivity parameter hloov kho tuaj yeem daws qhov teeb meem no zoo yam tsis muaj kev cuam tshuam rau kev ntsuas linearity. Raws li kev ntsuas kub los yog txheej txheem kub, kho raws li cov kauj ruam hauv qab no:
Piv txwv li, qhov ntau ntawm tus pas ntsuas kub yog: 500-1400 degree
Qhov tseeb kub yog 1200 degree, thiab ntsuas kub yog 1150 degree,
Hauv qhov no, emissivity parameter tuaj yeem hloov kho rau:
(1150-500) ÷ (1200-500)=0.928 ≈ 0.93
Tom qab xws li kev hloov kho, qhov ntsuas qhov tseem ceeb yog ze rau qhov tseeb qhov tseem ceeb, uas tuaj yeem hloov kho raws li "Cov Khoom Siv Emissivity Coefficient Table". Txawm li cas los xij, cov kev txwv hauv cov lus no yuav tsis tas yuav siv tau rau cov txheej txheem yuav tsum tau ua. Nws yuav tsum tau qhia meej tias lub ntsiab lus ntawm kev qhia txog kev hloov pauv emissivity yog los kho qhov ntsuas qhov yuam kev.
