Chapter
12
l2-l
Air@300K k-0.a262
Vertical plate GrPr – 104
; Nu : trllk : 54.2( TL)t t4
Fig l2-8 CrrPr
– 104 Nu :6
: lOe Nu:100
l2-2, Openended
problem
r2-3
d
: 15
mm T.
: 800
K T”
: 300K Ar : Az
: rdl2: 0.0236 nf m
4za
12-4
Water,
H:50 ffiffi,
W
– 25
mm Tr:300 K
Table
A-9:
Grpr
– (0.05)3(20Xl.9l
x
l0ro)
– 4.7gx
107
12-5
Air Fig.
l2-ll GrPr
– 3.5xl0s
12-6
L
– 5 m p: 1
atm,
u
– 300
milh: 134
m/s,
Tr:300 K
v- l5.2×10-6
k- 0.02624,pr:
A.7
– (134X5)/15.2×10-6
4rl
12-7
IrT:2900 p-K
:11600
12-g
Vertical
heater
surface
makes
no
sense
!
12-g
Re: 10000,
T
– 300
K, k
– 0.02624,Pr:
0.7
12-10
k-0.69,p-1600,c-800
h
– 1.42((4oo-3oo)/0.
tlr+
– g
Volume
– (0.05)(0.
1X0.2)
:0.001
m3
: (2)[(0.05X0.
0o/0i
4qo
12-ll
Tr:325K
v
– 13×10-6,
k- 0.024,
pr:0.7,w- 50,
L: 1.0
12-12
Reo
– (soxo.3)/l
3x l 0-6
– l.l5x
l
o6
– I154
12-13
Reo
– (50X0.002)115.7×10-6
– 6400;
k – 0.02624
o(t
– 55
4at
12-14
Open
ended
12-15
12-16
TF:325K
– (g.gx
h
.024)l
a
.002
12-17
– (g.gx(
– t.1x
12-18
4l “-
t2-19
Liquid
water
k:0.61
: (1.91
t2-20
Gr5Pr
: (9.8X
I /300X20X0.0
t
)3(.Zy(
t S. 7
xt0a)2
: I 865
t2-21
Pr
: I atm,
air
at 300 K 6: l0 cm, AT
:20oC,p2:0.000001
atm
reduction
12-22
12-23
d:4cm Tt:475
K Tz:300K,r1
:0.5,
tz:0.7
:4n(0.02)2:0.005
1,7
tza4
x
: 0.7,T
: 273
+200
: 473
K,d : 0.1
m
t2-25
p:0.1 MPa,
AT*: l0oC
Fig.12-23; h
=
0.0023
+?4
Chapter 12
l2-I
Air@300K
k-0.a262
Vertical
plate
GrPr
– 104;
Nu: hl,/k
:54.2$TC)rt4
Fig l2-8 CrrPr: 104 Nu :6
:100
l2-2 Openended
problem
t2-3
d: 15 mm T,: 800
K Ta
=
300K Ar
: & : ndl2:0.0236
m2m
Tr : 354
Il Tz
4rr
12-4
Wateq H – 50
mm, W
– 25 mm Tr:300 K
Table A-9:
GrPr
– (0.05)3(20X1.91x
toto)
– 4.78x 107
Fig.
12-14 umax
l2-5
Air Fig. l2-ll CrrPr
– 3.5×105
12-6
L -5 m p
– I atm,
u
– 300
mi/h
– l34m/s,
Tr: 300 K
{to
l2-7
Fig.
L2-9,
Fraction
l2-8
l2-9
Re
– 10000,
T – 300
K, k
– 0.02624,
Pr: 0-7
Taked:lcm-l0mm
* Pro’a
: 82.9
h
l2-la
k-0.69,p:1600,c-800
h
– 1.42((4oo-3oo)/0.
l)t’n
– 8
– (0.05)(0.
0/0i
4t’?
– Q.7
– (8X0.07/0.001)r/(1600)(800)
l2-ll
Tr:325K
v- 13xlOt,
k: 0.024, Pr- 0.7,w:50, L- 1.0
: (50X
q
12-12
Reu
– (50X0.
3)lI3
x
106
: 1. l5x 106
– (1300)(0.7)t
t3
– I 154
12-13
Reo
: (50X0.
002y 15 .7
xl 06
: 64AA; k – 0.02624
– 2yP#’ofu”Jpr*)t’n
: 55
1ts
12-14 Open
ended
l2-15
Tr: 325 K,
V: 18x10t,
k- 0.024,
Pr
: A,7
: (9.8X
l2-16
Tr:325K
: (g.SX
– n .3
h
12-17
CnPr
: (9.8X(
r1325X50)(0.07)'(0.
7y(L8x
106;z
– 1.1x
106
– A.3
l2-18
Fig. l2-12(a)
6 – 2.7
rnm
Fig. l2-1a(a) uman
: 17
mm/s
411
12-19
12-20
: (9.
7
xlo4)2 : I
865
t2-21
pr
– I atnU
air
at
300
K 6: l0 cnr”
AT
:20″C, p2
= 0’000001
atm
Percent
reduction
t2-22
= 6000
12-23
d
=
4
cm Tt:475 K Tz:300K Er
=
0.5, az:0.7
:4n(0.02)2:0.005
Ll(/0