C2 VF 2011 th2.pdf


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W34 =

T
xP1 '
v 2 − L 3 x + c f (T1 − T3 ) = xP1 v1 3 − L 3 x + c f (T1 − T3 ) (0,5pt) ;
2
T1

W34 = 16,39kJ (0,5pt) ;
W41 = − P1 v1 (0,5pt); W41 = −199,6kJ (0,5pt).
v
R
T1 ln 2 = P1 v1 ln 2 (0,5pt) ; Q12 = 138,35kJ (0,5pt) ;
M
v1
γp1 v1
= c P (T3 − T1 ) =
(T3 − T1 ) (0,5pt) ; Q '22 = −46,1kJ (0,5pt).
( γ − 1)T1

4/ Q12 =

Q '22

Q '23 = − L 3 (1 − x ) (0,5pt) ; Q '23 = −1890,52kJ (0,5pt) ;
Q 34 = 0 (adiabatique) (0,5pt) ;
Q 41 = L1 (0,5pt) ; Q 41 = 1932kJ (0,5pt).
5/ Wcycle = ∑ Wi , Wcycle = −133,91kJ (0,5pt).

Q cycle = ∑ Q i , Q cycle = 133,73kJ (0,5pt).

ηcycle = −

Wcycle

∑ Qi > 0

ηCarnot = 1 −

; ηcycle =

133,9
= 6,47% (0,5pt) ;
2070,35

T3
(0,25pt), ηCarnot = 6,6% > ηcycle (0,25pt).
T1

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