Heat Transfer

 

Ofnt Srngsbfr

 

Ifnrglgj Eakfhtlvfs Nt tof fgc eb tof teplh , tof stucfgts soeuic af naif te; >. Vgcfrstngc ofnt ns n ber` eb fgfrjy trngsbfr4 1. Lcfgby tof torff typfs eb ofnt trngsbfr.

 

Zont ls Ofnt5 •

Ofnt (^) ls cfgfc ns tof trngsbfr eb fgfrjy nhress tof aeugcnry eb n systf` cuf te n tf`pfrnturf clfrfghf aftwffg tof systf` ngc lts surreugclgjs.

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Zofg yeu ofnt suastnghf, nrf trngsbfrrlgj fgfrjy lgte lt ay pinhlgj lt lg nhegtnht wlto yeu surreugclgjs tont onvf n oljofr tf`pfrnturf. Xuho ls tof hnsf, ber fxn`pif, wofg yeu pinhf n png eb heic wntfr eg n stevf aurgfr. Sof aurgfr ls nt n oljofr tf`pfrnturf tong tof wntfr, ngc se tof wntfr jnlgs fgfrjy ay ofnt.

 

Vglt eb Ofnt  •

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 Hnierlf (hni) ‘ Cfgfc ns tof n`eugt eb ofnt gffcfc te rnlsf tof tf`pfrnturf eb > j eb wntfr ay > Arlso Sofr`ni Vglt (Atu) ‘ Cfgfc ns tof qungty eb ofnt

gffcfc te rnlsf tof tf`pfrnturf eb > ia eb wntfr ay > .

 

 

Sorff Sypfs eb Ofnt Srngsbfr >. Ofnt trngsbfr ay Hegcuheg 1. Ofnt trngsbfr ay Hegvfheg 8. Ofnt trngsbfr ay Qnclneg

 

Ofnt Srngsbfr ay Hegcuhtleg •

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Lg hegcuhteg, tof trngsbfr hng af rfprfsfgtfc eg ng nte`lh shnif ns ng fxhongjf eb dlgfh fgfrjy aftwffg `lhresheplh pnrhifs–`eifhuifs, nte`s, ngc brff fifhtregs–lg wolho ifss-fgfrjfh pnrhifs jnlg fgfrjy lg heiilslegs wlto `erffgfrjfh pnrhifs. Ber fxn`pif, lb yeu oeic egf fgc eb n iegj `ftni anr ngc lgsfrt tof etofr fgc lgte n n`f, yeu wlii gc tont tof tf`pfrnturf eb tof `ftni lg yeur ongc seeg lghrfnsfs.

 

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 Sof rntf eb fgfrjy trngsbfr ay hegcuheg ls

er Zofrf; ] 0 rntf rntf eb ofnt ew/fgfrjy trngsbfr trngsbfr er pewfr lg wns (K/s) d 0 tofr`ni hegcuhvlty eb tof `ntfrlni ∂S 0 hongjf lg tf`pfrnturf I/∂x 0 ifgjto er tolhdgfss N 0 hress-sfhegni nrfn

 

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 Ber n he`peugc sina hegtnlglgj sfvfrni `ntfrlnis eb tolhdgfssfs , , . . . ngc tofr`ni hegcuhvlfs , , . . . , tof rntf eb fgfrjy trngsbfr toreujo tof sina nt stfncy stntf ls

 

Fxn`pif > N oeusf   ls aulit eb arlhds, wlto wniis 1= h` tolhd. Sof wnii lg egf eb tof ree`s ree`s eb tols oeusf oeusf `fnsurfs `fnsurfs 6.= ` 8.= `. Zont Zont ls tof ofnt ew toreujo tols wnii lb tof lgslcf tf`pfrnturf ls 1> ngc tof eutslcf tf`pfrnturf ->?5

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  Xeiueg; •

Sof tf`pfrnturf hongjf nhress tof wnii ls ∂ S 86 . Ofghf, wlto d =.28 K/(s`H) bre` Snaif 1=.8, jlvfs

 

Fxn`pif 1 Se rfcuhf tof ofnt iess, tof ewgfr eb tof arlhd oeusf cfshrlafc lg Fxn`pif > hevfrs tof arlhd wnii wlto n >1-h` inyfr eb afrjinss lgsuineg. Zont ls tof ofnt iess gew5

 

  Xeiueg; •

 

Ofnt Srngsbfr ay Hegvfhtleg •

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 Lg hegvfhteg, tof ofnt ls sterfc lg n `evlgj ulc ngc ls hnrrlfc bre` egf pinhf te ngetofr ay tof `eeg eb tols ulc. Lb lt wfrf get ber hegvfheg hurrfgts, lt weuic af vfry clhuit te aeli wntfr. Ns wntfr ls ofntfc lg n tfndfif, tof iewfr inyfrs nrf wnr`fc rst. Sols wntfr fxpngcs ngc rlsfs te tof tep afhnusf lts cfgslty ls iewfrfc. Nt tof sn`f `f, tof cfgsfr, heei wntfr nt tof surbnhf slgds te tof aee` eb tof dfif ngc ls ofntfc.

Zofrf; ] 0 rntf eb ofnt ew lg wns N 0 surbnhf nrfn eb tof `fclu` wofrf `evlgj ulc ls prfsfgt o 0 hegvfheg hefhlfgt lg Z/ er hni/ S 0 hongjf lg tf`pfrnturf

 

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Sof sn`f prehfss ehhurs wofg n ree` ls ofntfc ay n rnclnter. Sof oet rnclnter wnr`s tof nlr lg tof iewfr rfjlegs eb tof ree`. Sof wnr` nlr Sof fxpngcs ngcheeifr rlsfs te hflilgj afhnusf eb lts iewfr cfgslty. cfgsfr, nlrtof bre` naevf slgds, ngc tof heggueus nlr hurrfgt pnfrg soewg lg Bljurf afiew ls fstnailsofc.

 

Fxn`pif 8 N  vfrhni stfn` plpf ons n cln`ftfr eb ? h` ngc ofljot eb 6 `. Sof tf`pfrnturf eb tof stfn` lg tof plpf ls oeur5 Sof hegvfhvf ofnt trngsbfr hefhlfgt ls >.:12 hni/

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Xeiueg; N 0 surbnhf nrfn eb tof plpf 0 0 ()(=.=?)(6) 0 >.162

 

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 Fxfrhlsf;

>. Sof ofnt trngsbfr bre` n 1 ` cln`ftfr spofrf te n 16 nlr strfn` evfr n pfrlec eb `f lgtfrvni eb > oeur ls 8=== dK. Fs`ntf tof surbnhf tf`pfrnturf eb tof spofrf lb tof ofnt trngsbfr hefhlfgt ls >= Z/. Ngswfr; 8>.2

 

Ofnt Srngsbfr ay Qnclntleg • •

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Lg   rnclnteg , tof ofnt ls hnrrlfc bre` egf pinhf te ngetofr ay fifhtre`njgfh wnvfs–ber fxn`pif, iljot wnvfs, lgbrnrfc wnvfs, er rncle wnvfs. Nii eakfhts rnclntf fgfrjy heggueusiy lg tof ber` eb fifhtre`njgfh wnvfs precuhfc ay tofr`ni vlarnegs eb tof `eifhuifs.

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Sof rntf nt wolho ng eakfht rnclntfs fgfrjy ls preperegni te tof beurto pewfr eb lts naseiutf tf`pfrnturf. Dgewg ns Xtfbng“s inw, tols afonvler ls fxprfssfc lg fquneg ber` ns

Zofrf; ] 0 pewfr lg wns N 0 surbnhf nrfn f 0 f`lsslvlty eb tof rnclngj surbnhf

0 tof Xtfbng-Aeitz`ngg hegstngt fquni te 6.22:3= S 0 surbnhf tf`pfrnturf lg Dfivlg

 

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Sof vniuf eb f hng vnry aftwffg zfre ngc uglty cfpfgclgj eg tof prepfrfs eb tof surbnhf eb tof eakfht. Sof f`lsslvlty ls fquni te tof naserpvlty, wolho ls tof brnheg eb tof lghe`lgj rnclneg tont tof surbnhf naseras. Ng lcfni naserafr ls cfgfc ns ng eakfht tont naseras nii tof fgfrjy lghlcfgt eg lt, ngc ber suho ng eakfht, f 0 >. Ng eakfht ber wolho f 0 > ls efg rfbfrrfc te ns n ainhd aecy.

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Qnclneg ls tof egiy `fhongls` eb ofnt trngsbfr tont hng hnrry ofnt toreujo n vnhuu`4 ber lgstnghf, tof ofnt eb tof Xug rfnhofs tof Fnrto ay rnclneg.

 

Fxn`pif 3 Sof   tugjstfg in`fgt eb ng lghngcfshfgt iljot auia ls nt 81== D. Sof in`fgt wlrf ons n cln`ftfr eb =.=? `` ngc 2 h` iegj. Nssu`lgj tof f`lsslvlty f 0 >, hnihuintf tof pewfr rnclntfc ay tof in`fgt.

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Xeiueg; N 0 cI 0 0

 

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 Fxfrhlsfs;

>. N ainhdaecy ons n tf`pfrnturf eb 6==. Zont soeuic lts tf`pfrnturf af lg ercfr tont lt rnclntfs twlhf ns `uho fgfrjy pfr sfhegc5 Ngswfr; 232.16 1. N heppfr anii 1 h` lg rnclus ls ofntfc lg n burgnhf te 3==. Lb lts f`lsslvlty ls =.8, nt wont rntf cefs lt rnclntf fgfrjy5 Ngswfr; >:.63 Z

 

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Qfbfrfghf; O.H. Eonglng & K. S. S. @nrdfrt. ]oyslhs ber Fgjlgffrs ngc Xhlfgsts. (8rc  fc.) ber Xhlfgsts ngc Q. N. Xfrwny & K. Z. Kfwf, Kr. ]oyslhs to Fgjlgffrs wlto @ecfrg ]oyslhs. (?  fc.)