aplikasi termodinamika-d3.ppt

8/18/2019 APLIKASI TERMODINAMIKA-D3.ppt

1/21

APLIKASI

TERMODINAMIKA


2/21

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


3/21

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


4/21

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

=


5/21

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


6/21

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%


7/21

QW z g u

H s +=∆+∆

+∆2

2

( )12

2

12 2 H H uu −−=

Subsonic:M


8/21

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*


9/21

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!


10/21

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


11/21

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=


12/21

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 −=∆=


13/21

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=∆=


14/21

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


15/21

S!eam Po1er Pla!

0Pemba$ki! Tea$a 7ap2

4+OILER


16/21

Siklus Termodiamika Pemba$ki!

Tea$a 7ap pada dia$ram TS


17/21

Re&ri$era!or

(eneric(enericRefri"erationRefri"eration

)*c$e)*c$e


18/21

Thermod'ami% '%le


19/21

T'pi%alRe&ri$era!io

'%le


20/21

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


21/21

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#

aplikasi termodinamika-d3.ppt

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