Transferencia de Calor
July 19, 2022 | Author: Anonymous | Category: N/A
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Fuàg Ch Trmnlh`gs 7 Hjhreoeom 7 Uh gàslg uk euhrpm quh thkh ukg suphrbeoh ch 744 e`> emk ukg lç`okg ch g`ogkm ch 3 e`. ch hsphsmr. Uo lg cohrhkeog ch h`phrgurg chl euhrpm emk hl h l `hcom hxhromr hs ch 744 ´E y hl ∞3 emhbeohkh ch emkcuetvocgc chl g`nohkh: ι 07 Ö 74 iegO / shf.e` ´E. Egleulgr euçkgs eglmràgs pgsgk g rgvïs ch lg lç`okg hk 7 amrg. Cgms: ∞3
ι 07 Ö 74
iegO / shf.e` ´E
W0 ½
ι ˟. U ∂ S ½ h
∞7 Ö 74∞˟ ∖744∖744 W0 ½ ½ 3
Shx0744 ´E
3
G0744 e`> h0 3 e`
W0˟ ½½ ?44 iegl
Hjhreoeom 5 Uh thkh ukg pgrhc cmnlh ch 7 `> ch suphrbeoh, sohkcm lg pro`hrg plgeg ch aohrrm ch > e`. ch hsphsmr y lg mrg ch emnrh ch 7 e`. ch hsphsmr. Uo hkrh lgs egrgs ch lg pgrhc hxosh ukg cohrhkeog ch h`phrgurg ch 544 ´ E. Egleulgr hl ujm eglõroem quh lm grgvohsg.
W 0 I ∟ G ∟ ^thr`oeg0 W0 ^70 ^>0 W0
L7
L> I > ∟ G
L I ∟ G
∂ S ^7 + ^> 4.4>
0
I 7 ∟ G
84.7 ∟ 7
>848
+
0
0 4.47 0 51? ∟ 7
544
7
∂ S ∂ Q
7
7 >848 7
51?44
0642453.5 V
51?44
Hjhreoeom 3 Cms uocms ch h`phrgurg 55´ E y -5 ´ E, rhsphetvg`hkh, sh hkeuhkrgk shpgrgcms pmr ukg pgrhc `últplh ch 75> e`> ch suphrbeoh euygs egpgs thkhk lms sofuohkhs hsphsmrhs: 54 e`., 74 e`. y 1 e`. Uus emhbeohkhs smk hk egcg egsm: 4y8iegl / `.a.´E9 4,>iegl/`.a.´E y 4,41iegl/`.a ´E, y
lms emhbeohkhs phloeulgrhs smk >4iegl /`> . a . ´ E y 58iegl/`> . a .´E.Egleulgr lms emhbeohkhs ch rgks`osoõk mgl I y lgs eglmràgs quh pgsgk g rgvïs ch lg pgrhc hk 7 amrg.
Egleulgkcm hl emhbeohkh ch rgks`osoõk mgl I
I tmtgl0
Ư h Ư
h I
0
4.5 4.8
4.31
+
4.7 4.>
+
0 4.>>186
4.41
Iegl `ÖaÖºE
4.41
Egleulgkcm hl emhbeohkh ch rgks`osoõk flmngl X
X Flmngl0
7
h 7 7 Ư I + + a 7 + a>
0
4.5
4.7
7 4.41
7
7
Iegl
04.38?
>
` ÖaÖºE
4.8 + 4.> + 4.41 + >4 + 58
Chhr`okgkcm lgs eglmràgs quh pgsgk g rgvïs ch lg pgrh hk 7 amrg
Wemkcueeomk 0X Ö G Ö ∂S 0 4.38? Ö 4.475> Ö 52 Ö 70>71 Iegl
Hjhreoeom 8 Xk amrkm ch gehrm euyg pgrhc hs ch 5 e`. sh `gkthkh g 344 ´E. Hsç rheunohrg pmr ukg egpg ch g`ogkm ch >4 e`. ch hsphsmr y lg h`phrgurg g`nohkh hs ch >4 ´E. Egleulgr: g) hl emhbeohkh ch rgks`osoõk mgl I, n) hl ujm eglmràbem pmr ukocgc ch suphrbeoh (q‟‟)9 Cgms: a egorh0 4,441egl/ e`>
.shf. ´E 9ι g`ogktm 04, ´E (g 344 ´ E)9 a egorh0 6,55 x 74∞ 3egl/ shf.e` > ´E (g >4 ´E)9 ι gehrm04,7>egl/e` .shf. 4447egl/e`.shf´E.
Cgms:
a egorh0 4,441egl/ e`> ´E Spgrhc0344 ´E h g`ogkm0 >4 e`
a egorh0 6,55 x 74∞3egl/ shf.e` > ´E ι gehrm04,7>egl/e`.shf.´E
a egorh0 6,55 x 74∞3egl/ shf.e` > ´E
Sg`nohkh0 >4 ´ E
ι g`ogktm 04, 4447egl/e`.shf´E.
W 0 I ∟ G ∟
I 0 ∟
∂ S h
h.W G . ∂ S ∞3
6,55 x 74 . G .514 4.4447 . G .514 W0 + 5 >4 W 0 4.4?36 G
I 0 ∟
I 0 8.6574
∞5
4.4?36 G
G . ( 344 ∞>4 )
w e`.´E
W w. e` G 04.4?36 s
Hjhreoeom 6 Umnrh egcg ukg ch lgs egrgs ch ukg pgrhc plgkg eoreulgk cms uocms hk emkrgemrrohkh. Hl uocm
B 7 sh hkràg chsch 68´E agsg suphrbeoh agsg 34´E y hl uocm uocm B > sh eglohkg chsch 58´E agsg 28´E. Lg suphrbeoh ch lg pgrhc hs ch 71 `> y hl vglmr chl emhbeohkh ch rgks`osoõk mgl chl eglmr hs c ch hI0 5>4iegl /a.` >,´E. Egleulgr lg egktcgc ch eglmr quh sh rgks`oh pmr amrg.
68´E
58´E
Blujm 7
Blujm >
34´E
28´E
X 05>4
iegl >
a ∟ ` ∟ ´ E
W 0X ∟ G∟∂ S Gsu`ohkcm ukg cohrhkeog ch h`phrgurg ch 58 ´E
W05>4
iegl
>
>
a ∟ ` ∟ ´ E
W0 (5>4 ∟ 71 ∟ 7 ) 5
W0 >47.2 x 74
∟ 71 ` ∟ 58 ´ E iegl >
a ∟ ` ∟ ´ E iegl >
a ∟ ` ∟´ E
Hjhreoeom 1 Hkemkrgr hl çrhg suphrbeogl chl blg`hkm ch ukfshkm ch ukg lç`pgrg ch 744 V. V . Lg h`osovocgc hs h 0 4,>8 y lg h`phrgurg S 0 >44 I. υ s0 3,?2 x 74∞1iegl / a.` >. I ∞ 3 (124 Iegl/ 07iVa)
Chhr`okgkcm hl çrhg `hcogkh lg heugeoõk ch rgkshrhkeog ch eglmr pmr rgcogeoõk
G s0
W
h Ö υ s Ö ( S ` ∞S L 3
3
)
0
12 ∞1
4.>8 Ö 3.?2 Ö 74
Ö ( 544 ∞>44 3
>
)
07.422??68 `>
Hjhreoeom ? Lg h`phrgurg ch lg pohl au`gkg hs gprmxo`gcg`hkh 58´E. ½Euçl hs lg lmkfouc ch mkcg poem hk lg rgcogeoõk quh h`oh= S058´E0541.78 I
∞>
ι`gxS 04..>1?1 x 74
` . I
ι `gx ( 541.78 ) 04..>1?1 x 74
∞>
∞2
ι `gx ½ ?.3 ?.34 4 74 `
Fuàg Ch Trmnlh`gs >
Hjhreoeom > Goslg`ohkm hk uk eugrm ràm. Egleulh lg pïrcocg ch eglmr pmr `> ch çrhg çrh g suphrbeogl hk lg pgrhc goslgkh ch uk eugrm ch gl`gehkg`ohkm hk ràm, so lg h`phrgurg hxhromr hs ch >2,1 ºE y lg okhromr ch 5,3 h sç mr`gcg pmr >8,3 `` ch emream prhksgcm emk uk vglmr ch i ch 4,4355 V/` I.ºE. Lg pgrhc hsç •
(^pg.: 5?,? V/`>)
W 0 I ∟ G ∟
∂ S ∂x
Blujm ch eglmr pmr ukocgc ch çrhg
W ∂ S >2.1 ∞5.3 0i ∟ 04.4355 ∟ G ∂x 4.4>83 W w 05?.? > G `
Hjhreoeom 5 Ch`uhsrh quh lg emkcueeoõk ch eglmr g rgvïs ch ukg pgrhc plgkg, fhkhrg uk phrbl lokhgl ch h`phrgurg hk hl okhromr ch lg pgrhc. Okcoegeoõk: g pgrtr ch lg heugeoõk cohrhkeogl ch emkcueeoõk, okhfrh pgrg llhfgr g ukg hxprhsoõk fhkhrgl S0 S(x).
^hglozgkcm hl nglgkeh ch hkhrfàg hk lg pgrhc chlfgcg.
( ) ( ) (
^gzmkch ^gzmkch emkcueeomk ∞ emkcueeomk + Fhkhrgeomk 0 ^gzmk ch eg`nom chhkhrfog cheglmr ch eglmr eglmr ch eg eglm lmrr hk hk k k+ ∂ k
Wk∞W k+∂ k + H fhk,hlh`hktm0
) (
)
∂ H hlh`hktm ∂ t
Hl eg`nom ch hkhrfàg chl hlh`hkm y lg fhkhrgeoõk ch eglmr sh puhchk hxprhsgr em`m:
∂ H hlh`hktm0 χeG ∂ k ( S t + ∂ t ∞S t )
H fhk,hlh`hktm0 h fhk G ∂ k Uustuyhkcm y chsphjgkcm
S ∞S ∞7 W k+ ∂ k ∞ W k + h fhk0 χe t +∂ t t G
∂ t
∂k
Hsgnlheh`ms lms lo`ohs eugkcm ∂ k y∂ t thkchk thkchk g 4 y mnhkh`ms lg h eugeoõk cohrhkeogl ch emkcuetvocgc vgrognlh:
7 ∎
G ∎ k
(
IG IG
)
∎ S ∎ S + h fhk0 χe ∎k ∎ t
Uh ochktbeg ukg heugeoõk cohrhkeogl ch shfukcm mrchk am`mfïkhg, su smlueoõk cohrhkeogl sh `uhsrg g emktkugeoõk:
Umlueoõk fhkhrgl:
>
∎ S h fhk 7 ∎S + 0 > I η ∎ t ∎k
(
)
(
)
∞ h fhk 7 ∎ S ∎ S + 0k + E 5 I ∎k η ∎ t
> k ∞h fhk 7 ∎ S + S (k )0 + E 5 k I η ∎t >
Hjhreoeom 3 Tïrcocg ch eglmr ch uk amrkm. Xk amrkm rhegkfulgr emk co`hksomkhs okhrkgs ch 7,4 ` x 7,4 ` x >,4 ` thkh uk frmsmr ch pgrhc ch 4,>4 `. Lg emkcuetvocgc i ch lgs pgrhchs h hss 4,?8 V/` I. Hl okhromr chl amrkm sh emkshrvg g 144 I y hl hxhromr g 584 I. Egleulh lg pïrcocg ch eglmr mgl chl amrkm. (^pg.: >7568 V) Gsuphrbeogl0 >(7+>+>)074 `> h04,>4 ` I04,?8 V/` I Sok0144 I Shx 0 584 I
W 0 I ∟ G ∟ W 0∟
∂ S h
4.?8 4.? 8 .74( 144∞ 584)
W 0 >7568 V
Hjhreoeom 2
4.>
Uh usg uk shrphkk ch hkrog`ohkm ch gehrm okmxocgnl okmxocgnlh h ch 7 poh ch lmkfouc, emk coç`hrm okhrkm ch 4,>8 pulfgcgs y coç`hrm hxhrkm ch 4,34 pulfgcgs, pgrg hxrghr eglmr ch uk ng÷m. Lg h`phrgurg hk lg suphrbeoh okhromr chl unm hs ch 34 ºB, y lg ch lg suphrbeoh hxhromr, ch 14 ºB. Lg emkcuetvocgc ïr`oeg chl gehrm okmxocgnlh hs 38 V/` I. Egleulh lg vhlmeocgc ch rgkshrhkeog ch eglmr. (^pg.: 3>54 V)
r 70 4.>8 pulf 0 7 poh 31
r >0 4.3 pulf 0 i 038
W ∟ lk W0
7 poh 54
w Ntu Ntu 0 38 ( 4.8661 ) 0>2 ` ∟ i a∟ bt ∟´ B a ∟ bt ∟´ B
( )0 r> r7
>∟τ∟z∟i∟∂S
>∟τ∟z∟i∟∂S lk
r> r7
()
> ∟ τ ∟ 7 poh∟ >2
W0 lk
Ntu W075?45.77 a
Ntu ∟ 34 ´ B a∟bt∟´B
( ) 31 54
0
>414 τ lk ( 7.2 )
Fuàg Ch Trmnlh`gs 5 Hjhreoeom 7 Xkg egrg ch ukg plgeg ch emnrh ch 5 e` ch hsphsmr sh `gkthkh g 344ºE y lg mrg egrg g 744ºE. Egleulgr lg rgpochz pmr `> emk lg quh hl eglmr sh rgksbhrh ch ukg plgeg g lg mrg.
Egleulgkcm lg rgpochz ch lg rgkshrhkeog ch eglmr
Wemkcueeomk G
∂ S 347 Ö ( 344∞544 ) V 0 0 34.7 Ö 742 > ∂x 4.445 `
0∞ I
Hjhreoeom > Uh smplg gorh g >4ºE smnrh ukg plgeg eglohkh ch 84e`x64e` quh sh `gkthkh g > >84ºE. 84ºE. hl emhbeohkh ch eglmr emkvhetvm hs ch >8 > 8 w/`>.ºE, egleulgr lg rgpochz emk lg quh sh cg lg rgkshrhkeog ch eglmr.
a0>8 w/`>.ºE
Gs04.58 `>
∂ S 0½ >54 ´E
W0 a . G s . ∂ S
W0 >8∖4.58∖>54 W0 >47>.8 V
Hjhreoeom 3 Cms plgegs khfrgs okbkogs g 144º E y 544ºE okhreg`nog eglmr pmr rgcogeoõk. Egleulgr lg rgkshrhkeog ch eglmr pmr ukocgc ch çrhg.
3
W0 θ ∟υ ∟ G∟S
S 707465.78 I S >0865.78 I υ 08.26 x 74
∞1
w >
3
9 θ 07
` ∟ i ∞ Wkhtm0W7∞W > W7 G
08.26 x 74∞1 ∟ 7 ∟ 7465.78 3068>47.>
W> G
08.26 x 74∞1 ∟ 7 ∟ 865.78 302771.28
Wkhtm
W
W
G
G
G
0 7 ∞ > 0 68>47.>∞ 2771.28
W w> G 0 2?41>.8 ` khtm
w > `
w > `
Hjhreoeom 8 Xk pgkhl ch `ghrogl plçstem ch çrhg 4,7`> y hsphsmr 4,284 e`, emkcueh e mkcueh hl eglmr hk hsgcm hsgeomkgrom emk ukg vhlmeocgc ch 5 wg sohkcm lg h`phrgurg ch lg suphrbeoh hxhrkgs smk S 40 >3ºE y S 70 >2ºE. ½Euçl hs hl vglmr ch lg emkcuetvocgc eglmràbeg hxprhsgcg hk egl/shf.ºI.e`=
Lg emkcuetvocgc eglmràbeg puhch shr egleulgcg çeol`hkh
I 0
W emkcueeomk Ö ∂ x G Ö ∂ S
0
5 Ö 4.4428 V 0 ?.68 Ö 74∞ 3 4.7 Ö > e`Ö I
Hjhreoeom 2 Egleulh lg phrcocg ch eglmr pmr `> ch çrhg ch suphrbeoh pgrg ukg pgrhc emkstuocg pmr ukg plgkeag ch bnrg goslgkh ch >8,3 `` ch hsphsmr, euyg e uyg h`phrgurg hs ch 58>,6ºI. h0>8,3
∂ S 058>,6 ºI 06?.88 ´E Ibnrg goslgkh04.435
W 0 I ∟ G ∟
w e`.´E
∂ S h
W ∂ S 0 I ∟ G h W 4.435∖6?.88 0 G >8.3 7444
W V 0753.26 > G `
Hjhreoeom 1 Cms suphrbeohs phrheg`hkh khfrgs hsçk emksruocgs ch gl `gkhrg quh mcg lg hkhrfàg orrgcogcg quh chjg ukg ch lgs suphrbeohs g 144 ºE llhfg agsg lg mrg suphrbeoh. Lg h`phrgurg ch hsg mrg suphrbeoh sh `gkthkh g >84ºE. egleulgr lg rgkshrhkeog ch eglmr hkrh lgs suphrbeohs pmr amrg y ukocgc ch çrhg.
3
W0 θ ∟ υ ∟ G ∟ S
S 707465.78 I S >08>5.78 I υ 08.26 x 74
∞1
w >
∞3
` ∟ i
9 θ 07
W khtm 0W 7∞W > W7 G
0 8.26 x 74∞1 ∟ 7 ∟ 7465.78 3068>47.>
W> G
0 8.26 x 74∞1 ∟ 7 ∟ 8>5.78 30 3>36.42
w > `
w > `
Wkhtm
W
W
G
G
G
0 7 ∞ > 0 68>47.>∞ 3>36.42 Wkhtm G
064?83.73
w > `
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