TRUY N NHI T V THI T B TRAO I NHI T

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

L qu trnh trao i nhi t, trong 1, 2 ho c 3 d ng trao i nhi t x y ra ng th i.

Nghin c u v trao i nhi t h n h p c n xem xt d ng trao i nhi t no l c b n, c nh h ng l n, cc d ng khc c tnh n thng qua m t s h s hi u ch nh.

TRAO I NHI T H N H P

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

Trao i nhi t gi a b m t v t r n v i ch t kh ( nhi t khng l n):

V D V NGHIN C U TRAO I NHI T H N H P

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

( )

( ) ( ) ( ) ( )fwbxdlfwfwfw

qd

dl

fwqdfwdlbxdl

TTTTTT

TTC

q

TTCTTqqq

+=

+=

+=+=

44

0

44

0

100100

100100

L qu trnh trao i nhi t gi a 2 mi tr ng ch t l ng ho c ch t kh c nhi t khc nhau qua m t vch ngn (m t d ng c a trao i nhi t h n h p).

Qu trnh truy n nhi t bao g m: - Trao i nhi t gi a mi tr ng c nhi t

cao v i b m t vch ngn (ch y u i l u),

- D n nhi t qua vch ngn, - Trao i nhi t (ch y u i l u) gi a vch

ngn v i mi tr ng c nhi t th p.

TRUY N NHI T

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

TRUY N NHI T QUA VCH PH NG

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ][ ]

( ) ( ) [ ]2211

2121

2

211

2

211

W/m11

W/m11

11

W/11

++

==

++

==

++=

nff

ff

n

n

ttttkq

KR

k

KmR

x1

t

tw11

tw2

tw3

tw4

2 3

2 3

tf1

tf2

1

2

TRUY N NHI T QUA VCH TR

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ][ ]

( )( ) [ ]W/m

1ln211

W/m1W/

1ln211

221

1

11

21

21

221

1

11

ddd

d

tt

ttkq

KR

k

mKdd

dd

R

n

i

i

i

ff

ffll

ll

n

i

i

il

pipipi

pipipi

++

=

=

=

++=

+

+

rr1

t

tw11

tw2

tw3

tw4

2 3

r2r3

r4

1tf1

tf22

[ ][ ]

( )( ) [ ]W/m

1ln211

W/m1W/

1ln211

221

1

11

21

21

221

1

11

ddd

d

tt

ttkq

KR

k

mKdd

dd

R

n

i

i

i

ff

ffll

ll

n

i

i

il

pipipi

pipipi

++

=

=

=

++=

+

+

TRUY N NHI T QUA VCH C CNH

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ]

[ ]( ) [ ]

( ) [ ]

( ) [ ]222

1

1

21

11

22111

21

21

22111

W/m11

W11

W

W/1

W/11

FFtt

FQq

FFF

ttQ

ttkQ

KR

k

KFFF

R

ff

ff

ffc

cc

c

++

==

++

=

=

=

++=

tw1

tw2

tf11

tf2

2

F1

F2

Tng c ng cc d ng trao i nhi t c b n :

- D n nhi t : gi m chi u dy vch, tng , tng T

- i l u : tng t c chuy n ng, tng T

- B c x : tng en, tng T, tng T,Tng c ng truy n nhi t qua vch : tng

h s to nhi t pha vch c gi tr nh ho c lm cnh (b qua nhi t tr d n nhi t).

TNG C NG TRUY N NHI T

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

gi m m t dng nhi t dng v t li u c nh (v t li u cch nhi t).

V i vch ph ng: tng chi u dy cch nhi t q gi m.

V i vch tr :

CCH NHI T - NG KNH T I H N

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

( )( )

2;2

012

1min

1ln21ln

211

2

2

22

221

2

111

===

===

+++=

cn

thth

cnth

cncncncn

ll

cn

cn

cnl

dBid

ddddRdkhiR

ddd

dd

dR

pipi

pipipipi

m b o

Ho c

Rl1 - nhi t tr i l u trong vch Rl2 - nhi t tr i l u ngoi vch Rlcn - nhi t tr d n nhi t l p cch nhi t

B C CCH NHI T VCH TR

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

2

2

cnthcn dd =>

22 cn

cnd

Rl

dcnd1=d2

Rl1

Rl2

Rlcn

Rlt

dth

nh ngha : l thi t b th c hi n s trao i nhi t gi a 2 ch t t i nhi t c nhi t khc nhau.

Phn lo i :- Ki u vch ngn : ho t ng lin t c, n

nh;- Ki u h i nhi t : ho t ng theo chu k,

khng n nh; - Ki u ng nhi t : tr ng tr ng, mao d n, ly

tm;- Ki u h n h p : trao i nhi t + trao i

ch t

THI T B TRAO I NHI T

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

KI U H N H P

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

Bi ton thi t k : xc nh di n tch b m t trao i nhi t theo nh ng yu c u ra.

Bi ton ki m tra : ki m tra nhi t cu i c a ch t t i nhi t.

TNH TON THI T B TRAO I NHI T KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

Ph ng trnh truy n nhi t: t: logarit hay s h c

Ph ng trnh cn b ng nhi t:

W = GCp l nhi t dung ton ph n [W/K] (1) - nng ; (2) - l nh ; () - vo; () - ra.

TNH TON THI T B TRAO I NHI T KI U VCH NGN

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

tkFQ =

( ) ( )( ) ( )

( ) ( ) ( )( ) 12

'2

"2

"1

'1

2

1'2

"22

"1

'11

'2

"222

"1

'111

'2

"22

"1

'11

WWWW =

===

==

==

tttt

ttttttQ

ttCGttCGQ

iiGiiGQ

pp

Nhi t trung bnh lgarit:

Nhi t trung bnh s h c:

XC NH CHNH NHI T TRUNG BNH (song song)

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ]Ktt

ttt

min

max

minmax

ln

=

[ ][ ]KtttKttttt

2

22minmax

"2

'2

"1

'1

+=

+

+=

F

t

tm

ax

tm

int1

t1

t2

t2

F

t

tm

ax

tm

in

t1

t1

t2

t2

t xc nh b ng th

XC NH CHNH NHI T TRUNG BNH (c t nhau)

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ]

2

1'2

"2

"1

'1

max

2

max

'2

"2

min

max

minmax

;

),(

ln

tt

ttttR

tt

tttP

RPftt

K

tt

ttt

t

nctcn

nc

=

=

=

=

=

=

=

F

t

tm

ax

tm

in

t1

t1

t2

t2

XC NH CHNH NHI T TRUNG BNH (c t nhau)

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

2

1'2

"2

"1

'1

max

2

max

'2

"2 ;

),(

tt

ttttR

tt

tttP

RPftt

t

nctcn

=

=

=

=

=

=

t xc nh b ng th

XC NH CHNH NHI T TRUNG BNH (c t nhau)

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

2

1'2

"2

"1

'1

max

2

max

'2

"2 ;

),(

tt

ttttR

tt

tttP

RPftt

t

nctcn

=

=

=

=

=

=

t xc nh b ng th

XC NH CHNH NHI T TRUNG BNH (c t nhau)

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

2

1'2

"2

"1

'1

max

2

max

'2

"2 ;

),(

tt

ttttR

tt

tttP

RPftt

t

nctcn

=

=

=

=

=

=

t xc nh b ng th

Bi t t 1, t2, W1, W2, tnh t1, t2 v i nhi t trung bnh s h c

TNH NHI T CU I CH T T I NHI T

Tr ng HBK H n i - Vi n KH&CN Nhi t-L nh - B mn K thu t nhi t /c: Phng 201 nh C7 HBK H n i T: (04) 8.692.333

[ ]

( ) ( )21

'2

'1

'2

"22

"1

'11

"2

'2

"1

'1

W211

W21

WW

22

++

=

==

=

+

+=

kF

ttQ

ttttQ

tkFQ

Kttttt

TRUYN NHIT V THIT B TRAO I NHITSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24