2稳态导热.pdf

文档介绍：ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
జnjజnj ிி
?2-1 
?2-2 ி

2005-8-2 1
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering

ሩ
 γ!"#நႋ&'"#() *+
8خ456 0123/
.-,
޻ABCD ࢨF=>1() ? ᇰ;:؀
#G
 H

ƑJKǎMN࡚P#
: H
2005-8-2 2
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
??22--11 
1 QRS (Temperature Field)
‰-U
VWX YX4Z"ȏ˷?ܖ^_`QRa
b> H
QRSc1dS e6Nc1df1B;
gH
QRSYXi<kXf1 lmni
oƑ QRSe;gp q
t = f (x, y, z,τ)
t—pQR ; x,y,z —pYXi ; τττ-kXi
2005-8-2 3
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
Šs
a) tkXu
ி QRS q"ȏ_`QRvtkXwx H
∂t
= 0 t = f (x, , zy )
∂τ
yி QRS qQRatkXwx H
∂t
≠ 0
∂τ t = f (x, y, z,τ)
b) tYXu
z ி QRS q t = f (x, , zy )
 ி QRS t = f (x)
2005-8-2 4
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
2 {Q|}{Qඥ
‰-U
{Q| qQRSƑWXQR_`€
|H
ඥ H…A{Q|p{Q̕ڣQඥ qlnj}
Š†`
a) QRv{Q|Z{Qඥ؎࡚vˆ‰Ǟ
b) l€‹QRSƑ {Q|Z{QඥvŒƑ
ࡘ҅Z"ȏƑ҈’“”…| •…
ඥ– Zҵ˜ࡘ}"ȏ™š
2005-8-2 5
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
c) "ȏƑ{QඥᇍœŸ QRx¡
¢ᇍ£ 
ऋƱᇍ£ H
9 9
9
9
9
2005-8-2 6
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
3 QR¦R •Temperature gradient –
QRx¡¢ࣵv¨໘v HQ
RࣵV¨ xx¡¢l1e6Nª
¨QR!iɯ
1B;g γ
∂t ∆ t
= lim
∂x∆x → 0 ∆ x
QR¦RN6¬­Q
ؓ†¡RSlYXx
"#d H
2005-8-2 7
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
o¯ƑV`ܖl{Q|}‰°{Q|
±XQ²}0ඥX³´±µ¶·
pª`QR¦R ၘp gradt H
∆t ∂t ∂t ∂t ∂t
gradt = Lim = nr = i + j + k
∆n→0 ∆n ∂n ∂x ∂y ∂z
¹qQR¦R¨d º࡙¨¼½QRHͪ
¨
2005-8-2 8
ΚƑܾ
ҔᏄҚ
HUST Lab of Thermal Science & Engineering
4 ÀÁÂ-. (Fourier ’s Law)
జÄƑÅ/ÆிÇÈAÀÁÂ-. É
H ̕ڣÁeÊ֭pÌ໘
λ n
∂t dt dn
q = − gradt = −λ n t t t+ dt
∂x 1
t2
ऋœRl x, y, z ¨ 0 x
¥ ؉£ÏÐpλ qݍ
λ
∂t ∂t ∂t
q = −; q = −; q = −λ
x ∂x