Apple Reference & Presen…rary 5 (Internal Edition)/Apple R&P Lib Internal v5.0.iso/6-Developer Demos/Developer Demos-Ed./Math CAD Demo/Sample Files/Heat Transfer

Text File | 1989-05-23 | 3KB | 199 lines

.MCD 30002 0
.CMD PLOTFORMAT logs=0,0 subdivs=1,1 size=5,15 type=l
.CMD FORMAT  rd=d ct=10 im=i et=3 zt=15 pr=3 mass length time charge
.CMD SET ORIGIN 0
.CMD SET TOL 0.001000
.CMD MARGIN 0
.CMD LINELENGTH 78
.CMD SET PRNCOLWIDTH 8
.CMD SET PRNPRECISION 4
.TXT 1 13 2 50
a1,50,50,43
HEAT TRANSFER -- FLAT WALL WITH TWO LAYERS
.TXT 2 -10 2 26
a1,26,26,26
First, define unit system
.EQN 2 6 1 9
ft~1L
.EQN 0 11 3 9
in~ft/12
.EQN 0 12 1 10
sec~1T
.EQN 0 13 1 9
lb~1M
.TXT 0 10 2 14
a1,14,14,14
(pounds mass)
.EQN 2 -23 1 15
hr~3600*sec
.EQN 2 -23 4 17
g~32.174*ft/sec^2
.EQN 0 23 1 12
lbf~lb*g
.EQN 0 20 3 21
Btu~20.031*ft*lbf/sec
.EQN 3 -20 1 20
J~0.07376*ft*lbf
.EQN 1 -23 3 9
W~J/sec
.EQN 1 23 1 10
degF~1
.TXT 0 18 4 22
a3,22,22,71
{for convenience, define
Farenheit degree as
dimensionless unit}
.EQN 5 -41 4 28
Â~1.713*10^-9*Btu/(ft^2*hr*degF)
.TXT 1 31 2 30
a1,30,30,28
(Stefan-Boltzmann constant)
.TXT 4 -37 2 25
a1,25,25,23
Parameters of problem:
.EQN 2 6 2 16
Area:25*ft^2
.TXT 1 36 2 11
a2,11,11,15
... wall
area
.TXT 2 -37 2 26
a1,26,26,27
First layer of wall: wood
.EQN 3 7 1 14
t1:.25*in
.TXT 0 28 2 11
a2,11,11,15
...
thickness
.EQN 2 -28 4 23
h1:4.1*Btu/(hr*ft^2*degF)
.TXT 1 28 2 22
a2,22,22,30
... inside convection
coeff.
.EQN 4 -28 3 23
k1:0.06*Btu/(hr*ft*degF)
.TXT 1 28 2 27
a2,27,27,36
... conductive coefficient
of wood
.EQN 3 -28 1 15
T0:75*degF
.TXT 0 28 2 28
a2,28,28,32
... maximum inside
temperature
.TXT 2 -35 2 44
a1,44,44,44
Second layer of wall: rock-wool insulation
.EQN 3 7 1 14
t2:.25*in
.TXT 0 28 2 11
a2,11,11,15
...
thickness
.EQN 2 -28 4 24
h2:21.8*Btu/(hr*ft^2*degF)
.TXT 1 28 2 23
a2,23,23,31
... outside convection
coeff.
.EQN 4 -28 3 24
k2:0.017*Btu/(hr*ft*degF)
.TXT 1 28 3 24
a3,24,24,46
... conductive
coefficient of
rock-wool
.EQN 3 -28 1 16
T4:-20*degF
.TXT 0 28 2 28
a2,28,28,33
... minimum outside
temperature
.TXT 2 -40 2 21
a1,21,21,20
Compute resistances
.EQN 2 7 3 16
Rh1:1/(h1*Area)
.TXT 1 30 3 22
a3,22,22,48
... convective
resistance,
inside surface
.EQN 3 -30 3 16
Rk1:t1/(k1*Area)
.TXT 1 30 3 22
a3,22,22,46
... conductive
resistance,
inside layer
.EQN 3 -30 3 16
Rk2:t2/(k2*Area)
.TXT 1 30 3 22
a3,22,22,47
... conductive
resistance,
outside layer
.EQN 3 -30 3 16
Rh2:1/(h2*Area)
.TXT 1 30 3 22
a3,22,22,47
... convective
resistance,
outside layer
.EQN 4 -30 1 31
Rtot:Rh1+Rk1+Rk2+Rh2
.TXT 0 33 2 16
a2,16,16,22
... total
resistance
.TXT 2 -43 2 25
a1,25,25,24
Heat flow, temperatures
.EQN 2 4 3 14
Q:(T0-T4)/Rtot
.EQN 0 22 3 19
Q=?Btu/hr
.TXT 1 19 2 33
a2,33,33,66
...rate of heat flow at time of
maximum   temperature difference
.EQN 4 -19 1 14
T0=?degF
.TXT 0 21 2 26
a2,26,26,32
... inside temperature
(given)
.EQN 2 -44 1 18
T1:T0-Q*Rh1
.EQN 0 23 1 18
T1=?degF
.TXT 0 21 2 25
a2,25,25,32
... temperature of
inside wall
.EQN 2 -44 1 18
T2:T1-Q*Rk1
.EQN 0 23 1 18
T2=?degF
.TXT 0 21 2 26
a2,26,26,32
... temperature between
layers
.EQN 2 -44 1 18
T3:T2-Q*Rk2
.EQN 0 23 1 18
T3=?degF
.TXT 0 21 2 26
a2,26,26,33
... temperature of
outside wall
.EQN 2 -21 1 15
T4=?degF
.TXT 0 21 2 27
a2,27,27,33
... outside temperature
(given)