transformari termotehnica

Transformarile simple ale gazului perfect Izocora

Izobara

Izoterma

Ecuatia transfom1arii

v=const

p=const

T=const

Exponentul n

n=

n=O

n =1

Dependenta dintre marimile de stare

PJ= -T,-

~=1_

Ji= Vz

I ±oo Tz

Pz

Vz

I

Tz

~

Pz

I

Cal dura specifica Cantitatea de cal dura

±oo

Cp

Cv

Q 12 = m · cJT2

-

T, )

Qlz = m·cP(Tz -I;)

Ql2 =L12

v

Qlz

Ql2 = - (pz- PJ

x- 1

= PJ . ~

·ln Vz VI

Q12 =m·r·T·lnli Pz

Lucru mecanic specific

Llz =0

Llz = p(Vz -

V';)

Vz L12 =PI·~ ·ln~

L 12 = m · r · (T2 - ~)

L 12 = m · r · T · In fi

Pz

Variatia entalpiei Variatia energiei interne Reprezentarea in p-v

Hz -H~ =Q1z +V(pz- PJ

H2-Hl=QI2

H 2 -H 1 =m·cP(T2 -T,)

H 2 -H 1 =m·cP(T2

Uz -U~ =Qlz =m·cv(Tz -T,)

Uz -U~ = Q1z -Liz

v

Uz -U~ = Q1z = - - (pz- PJ

U z - Ul

-r;) U 2 -U1 =O

= ri't. C,, (Tz - T,)

x- 1

p

2

p

P2

--·U p,=p2

P1

r-. .

I Pi--;----

I

J

I

~

T, -

11 S1

I I I I l S2

T, s

.

v,

v

v2

-

2

{~

v2

T

T Tz

1

I I I

I !

v1

-----

--,

IJio

v

T

P2

2

1

---n 1

T2

p

'

I I I

I

Reprezentarea in T-s

H 2 -H1 =0

2

T1=Tz

~~ 1 'I I I I

1-'

l 1 S1

S2

1

' I I I

s

...

,.

2

I I I

l

I

S1

S2

s

I

Adiabata

Politropa Cn=const

X

n

Ecuatia transformarii Exponentul n Dependenta dintre marimile de stare

Ca1dura specifica

0

Cantitatea de cal dura

Lucru mecanic specific

V ariatia entalpiei H 2 -H 1 =U 2 -U1 +(p 2V2 H2

-

H1

-

c=

p 1v;)

n

n·c -c n-x v P=c-n-1 vn-1

= m · cP (T2 -I;)

V ariatia energiei interne U] -Uz =Llz

n=

cP

-en

logp1 -1ogp2

_

= --=:....::......!---=..:......::.. log V2 -log v;

log Vz

v;

U 1 - U 2 = m · cv (I; - T2 ) Reprezentarea in p-v

p

p

,.

Reprezentarea in T-s

T

:.j-----

T

2

r-~-r----r-

\

I

n<·.;\ n=·; !. '\,.'.,

T

i T,

2

2

./1

i

......

i

n>y

/

· /1

r···-.............................. 1 s

...............::.

k =S>_ c,.

logEL P2