aplikasi termodinamika-d3.ppt
TRANSCRIPT
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APLIKASI
TERMODINAMIKA
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APLIKASI TERMODINAMIKA
PADA PROSES ALIR
Fluida:
0 ;0 ≠≠ κ β Fluida kompresibel : volume berubah karea !ekaa a!au
perubaha suhu" mis# $as
Fluida ikompresibel : volume tidak berubah karea !ekaa
a!au perubaha suhu" sua!u idealisasi " %aira hampir bisa
dia$$ap seba$ai &luida ikompresibel#
P T
V
V
∂
∂=
1β
T P
V
V
∂∂
−=1
κ
Akspasivi!as volume
Kompresibili!as Iso!ermal
Ma!eri 'a$ bisa me$alir( $as a!au %aira
0 ;0 == κ β
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Alira Fluida dalam Pipa
( ) ( )
=
=
kg m
mm/s
V
Au
V
Au
mm
/
(kg/s)
3
2
2
22
1
11
21 Pers# Ko!iui!as :
) *
dx
dS C
u
T dx
duu P
−
+=
2
22
1 M
Mβ
dx
dS C
u
V
T
dx
dP P
−
+−=
2
2
1
1
M
β
0>dx
du
0<dx
dP
0>dx
dS
+ila$a Ma%h M = u/c;
c = kecepatan suara
M* , ) subsoi%
irreversible
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Fluida ikompresibel proses irreversible
dT C dH P =( )VdP T dT C dH P β −+= 1
VdP T
dT C dS P β −=
T
dT C dS P =
0 ;0 == κ β
0>dS
0>dT 12 T T >a!au
2
22
1
11
V
Au
V
Au=
2121 dan V V A A == 21 uu
=
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VdP TdS dH +=
VdP dT C dH P
+=
21 uu =
0=∆ H
QW z g
u
H s +=∆+
∆
+∆ 2
2dP V dT Cp −=
( ) ( )1212 P P V T T Cp −−=−
12 T T >
12 P P
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No--les ad Di&&users
A diffuser conerts !i"!
speed# $o% pressuref$o% to $o% speed# !i"!
pressure f$o%
A no&&$e conerts !i"!
pressure# $o% speed
f$o% to $o% pressure#
!i"! speed f$o%
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QW z g u
H s +=∆+∆
+∆2
2
( )12
2
12 2 H H uu −−=
Subsonic:M
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Thro!!li$
T!rott$in"'a$e
QW z g u
H s +=∆+∆+∆2
2
0=∆ H Cons&an& en&'a"p
or idea" gas: 0=∆ H 12 H H = 12 T T =
or os& rea" gas a& odera&e condi&ions o! &epera&ure and pressure% a reduc&ion
in pressure a& cons&an& en&'a"p resu"&s in a decrease in &epera&ure*
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Me$hi!u$ ./ da .S 0revie12
∫ ∫ ==∆ T
T
ig
P T
T
ig
P
ig dT R
C RdT C H
00
00
"n"n00 P
P RT
dT
R
C R
P
P RT
dT C S
T
T
ig
P T
T
ig
P
ig −=−=∆ ∫ ∫
3ika !ersedia !abel 0sp! !abel uap4s!eam !able2 pakai
./ 5 /* 6 /)
Da .S 5 S* 6 S)
7!uk o ideal $as 0real2 dibahas pd !ermodiamika la8u!
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Turbi
)( 12 H H m H mW S −=∆=
12 H H H W S −=∆=
eng'asi"kan ker.a aksiu .ika
proses adiaba&ik reversibe" (isen&ropik%
S1 S2)
S S H isentropicW )()( ∆=
+'e &urbine e!!icienc
S S
S
H H
isentropicW W
)()( ∆∆=≡η
a"ues !or proper" designed &urbines: η 0* 0*
QW z g u
H s +=∆+∆
+∆2
2
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4 s&ea &urbine #i&' ra&ed capaci& o! 56700 k8 opera&es #i&' s&ea
a& in"e& condi&ions o! 600 k9a and 500C% and disc'arge in&o a
condenser a& a pressure o! 10 k9a* 4ssuing a &urbine e!!icienc o!
0*5% de&erine &'e s&a&e o! &'e s&ea a& disc'arge and &'e ass ra&e o!
!"o# o! &'e s&ea*
S W +urbine
K kg kJ S
kg kJ H
C T kP P
⋅==
==
65*66*331
500600
11
11
K kg
kJ S kP P
⋅
=′= 65*610 22
K kg kJ x xS xS xS
!!!!" !
⋅=+−=+−=′ 65*61511*673*0)1()1( 222
07*0=! xkg kJ H x H x H !!" !
7*211)1( 222 =+−=′
( )kg kJ H H H S 2*12712 −=−′=∆
( )kg kJ H H S 6*55−=∆=∆ η
!!" ! H x H xkg kJ H H H 2212 )1(0*2736 +−==∆+=
3*0=! x K kg
kJ S xS xS !!" ! ⋅=+−= 676*)1( 222
skJ H mW S 56700=∆=
skg
m 02*5=
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9 Tekaa mei$ka!
9 Kompresor u!k $as( pompa u!k %aira
9 Membu!uhka ker8a4eer$i dari li$ku$a
)( 12 H H m H mW S −=∆=
12 H H H W S −=∆=
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Sa&ura&ed-vapor s&ea a& 100 k9a (&sa& *63 C ) is copressed
adiaba&ica"" &o 300 k9a* =! &'e copressor e!!icienc is 0*5% #'a& is
&'e #ork re>uired and #'a& is &'e #ork re>uired and #'a& are &'e
proper&ies o! &'e disc'arge s&rea?
or sa&ura&ed s&ea a& 100 k9a: K kg
kJ S
⋅= 35*1
kg
kJ H 7*2651 =
=sen&ropic copression
K kg
kJ S S
⋅==′ 35*12
300 k9a
kg
kJ H *22 =′ ( )
kg
kJ H S 7*213=∆
( )
kg
kJ H H S 5*27=
∆=∆
η kg
kJ H H H *2512 =∆+=
300 k9aC T 1*2762 =
K kg
kJ S
⋅= 501*2
kg
kJ H W S 5*27=∆=
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9opa
Prisip sama de$a kompresor( !e!api
pompa untuk cairan
( ) )()( 12 P P V H isentropicW S s −=∆=
dP T V dT C dH P )1( β −+= VdP T dT C dS P β −=
P T V T C H P ∆−+∆=∆ )1( β P V T
T C S P ∆−=∆ β
1
2"n
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S!eam Po1er Pla!
0Pemba$ki! Tea$a 7ap2
4+OILER
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Siklus Termodiamika Pemba$ki!
Tea$a 7ap pada dia$ram TS
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Re&ri$era!or
(eneric(enericRefri"erationRefri"eration
)*c$e)*c$e
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Thermod'ami% '%le
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T'pi%alRe&ri$era!io
'%le
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ompoe!s
9 Re&ri$era! 01orki$
&luid2
9Evapora!or4hiller
9 ompressor
9 odeser
9 Re%eiver
9 Thermos!a!i%
e;pasio valve 0T
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Re&ri$era!
9 Desirable proper!ies:
> /i$h la!e! hea! o& vapori-a!io 6 ma; %ooli$
> No6!o;i%i!' 0o heal!h ha-ard2
> Desirable sa!ura!io !emp 0&or opera!i$ pressure2 > hemi%al s!abili!' 0o6&lammable4o6e;plosive2
> Ease o& leak de!e%!io
> Lo1 %os!
> Readil' available
9 ommol' use FREON 0R6)*( R6))?( e!%#2( bu! o1 i! is
prohibi!ed be%ause i! %auses o-o deple!io#