Qhov sib txawv tseem ceeb ntawm thermal conductivity thiab heat transfer coefficient yog qhov thermal conductivity muaj feem xyuam rau lub spatial molecular diffusion ntawm cov cua sov thoob plaws hauv cov kua, whereas heat transfer coefficient yog proportionality tas li ntawm cov khoom cua sov thiab lub thermodynamic tsav tsheb. ntawm tshav kub ntws los ntawm chav tsev.
Thermal conductivity yog lub peev xwm ntawm cov khoom siv los ua kom sov los ntawm nws tus kheej. Thaum tshav kub kub hloov coefficient, ntawm qhov tod tes, yog qhov proportionality tas li ntawm lub tshav kub flux thiab lub thermodynamic tsav quab yuam rau ntws ntawm tshav kub.
Tus nqi hluav taws xob yog dab tsi?
Thermal conductivity tuaj yeem piav qhia raws li lub peev xwm ntawm cov khoom siv los ua kom sov los ntawm nws tus kheej. Peb tuaj yeem siv peb txoj hauv kev los qhia lo lus no: k, λ, lossis κ. Feem ntau, cov khoom siv uas muaj cov thermal conductivity siab qhia qhov siab ntawm kev hloov hluav taws xob. Piv txwv li, cov hlau feem ntau muaj cov thermal conductivity siab thiab muaj txiaj ntsig zoo hauv kev ua cua sov. Hauv qhov sib piv, cov ntaub ntawv insulating xws li Styrofoam muaj cov thermal conductivity tsawg thiab qhia qhov qis ntawm cov cua sov hloov. Yog li ntawd, peb tuaj yeem siv cov ntaub ntawv nrog cov thermal conductivity siab nyob rau hauv cov ntaub ntawv kub dab dej thiab cov ntaub ntawv uas tsis muaj thermal conductivity nyob rau hauv thermal rwb thaiv tsev daim ntaub ntawv. Ntxiv mus, "thermal resistivity" yog reciprocal ntawm thermal conductivity.
lej, peb tuaj yeem qhia cov thermal conductivity li q=-k∇T, qhov twg q yog cov cua sov flux, k yog thermal conductivity, thiab ∇T yog qhov kub thiab txias. Peb hu qhov no "Fourier txoj cai ntawm kev ua cua sov."
Peb tuaj yeem txhais cov thermal conduction raws li kev thauj mus los ntawm lub zog vim yog qhov kev txav ntawm cov molecular random hla qhov ntsuas kub. Peb tuaj yeem paub qhov txawv ntawm lo lus no los ntawm kev thauj mus los ntawm lub zog los ntawm kev ua haujlwm ntawm convection thiab molecular vim tias nws tsis cuam tshuam nrog kev siv cov microscopic ntws los yog kev ntxhov siab sab hauv uas ua haujlwm tau zoo.
Thaum xav txog cov ntsuas ntsuas rau thermal conductivity, SI units yog "Watts ib meter-Kelvin" lossis W / mK. Txawm li cas los xij, hauv imperial units, peb tuaj yeem ntsuas thermal conductivity hauv BTU / (h.ft.°F). BTU yog British thermal unit, qhov twg h yog lub sij hawm hauv teev, ft yog qhov deb ntawm ko taw, thiab F yog qhov kub hauv Fahrenheit. Tsis tas li ntawd, muaj ob txoj hauv kev loj los ntsuas qhov thermal conductivity ntawm cov khoom: khov kho-lub xeev thiab txoj kev hloov pauv.
Hua Kub Hloov Coefficient yog dab tsi?
Kub hloov pauv coefficient yog qhov sib npaug ntawm qhov sib npaug ntawm cov cua sov thiab cov cua sov ua kom sov rau kev khiav ntawm cua sov. Nws tseem hu ua zaj duab xis coefficient lossis zaj duab xis ua haujlwm hauv thermodynamics. Feem ntau, tag nrho cov nqi hloov hluav taws xob rau qee lub tshuab yog qhia nyob rau hauv cov nqe lus ntawm tag nrho cov conductance los yog kub hloov coefficient, uas yog denoted los ntawm U.
Lub tshav kub hloov pauv coefficient yog qhov tseem ceeb hauv kev suav cov hloov hluav taws xob los ntawm kev sib hloov los yog theem hloov ntawm cov kua thiab cov khoom. Thaum xav txog SI units, qhov kub hloov pauv coefficient muaj cov units W / (m2K) (watts ib square meter Kelvin).
Ntxiv mus, qhov sib txawv ntawm cov cua sov tuaj yeem piav qhia raws li qhov sib txuam ntawm thermal insulation. Peb tuaj yeem siv cov coefficient hloov tshav kub rau cov khoom siv hauv tsev thiab rau cov khaub ncaws rwb thaiv tsev.
Qhov txawv ntawm Thermal Conductivity thiab Heat Transfer Coefficient yog dab tsi?
Thermal conductivity thiab heat transfer coefficient yog cov ntsiab lus tseem ceeb hauv chemistry lub cev. Qhov sib txawv tseem ceeb ntawm thermal conductivity thiab heat transfer coefficient yog qhov thermal conductivity muaj feem xyuam rau qhov sib txawv molecular diffusion ntawm cov cua sov thoob plaws hauv cov kua dej, whereas tshav kub hloov coefficient yog proportionality tas li ntawm cov khoom siv hluav taws xob thiab cov thermodynamic tsav lub zog ntawm cov cua sov ntws los ntawm cov dej. chav tsev.
Cov lus hauv qab no qhia txog qhov sib txawv ntawm thermal conductivity thiab heat transfer coefficient.
Summary – Thermal Conductivity vs Heat Transfer Coefficient
Qhov sib txawv tseem ceeb ntawm thermal conductivity thiab heat transfer coefficient yog qhov thermal conductivity muaj feem xyuam rau lub spatial molecular diffusion ntawm cov cua sov thoob plaws hauv cov kua, whereas heat transfer coefficient yog proportionality tas li ntawm cov khoom cua sov thiab lub thermodynamic tsav tsheb. ntawm tshav kub ntws los ntawm chav tsev.
