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English Pages [6] Year 2021
Derivation of the differential equation of entropy generation rate
t.me/exergy_destruction
q q + dy dx T y y T y
q dy T x
ρvs + y ( ρvs ) dy dx
q q T + x T dx dy x x
y
ρs ( ) t dxdy
ρusdy y, v
x
x, u
q dx T y
ρvsdx
S g = −
Q S − ms + ms + T t i e t.me/exergy_destruction
ρus + ρus dx ( ) dy x
q q q q q q S gdxdy = + dx dy + + dy dx − dy − dx T x T y T y y T y T x x T x + ρus + ( ρus ) dx dy + ρvs + ( ρvs ) dy dx − ρusdy − ρvsdx x y ( ρs ) + dxdy t
q S g = x x T
qy + y T
+ ρus + ρvs + ( ) ( ) ( ρs ) y t x
1 qx qx T 1 q y q y T ρ u s ρ v s s ρ Sg = − 2 + − 2 + us + ρs + ρu + vs + ρs + ρv + ρ + s T x T x T y T y x x x y y y t t t.me/exergy_destruction
s u v 1 qx q y 1 T T s s ρ ρ ρ S g = + + qy − 2 qx + ρ + u + v + s + u + v + ρ + T x y T x y x y t x y t x y
S g =
1 1 Ds 1 1 Ds Dρ .q − 2 q.T + ρ +s + ρ.V → S g = .q − 2 q.T + ρ T T Dt T T Dt Dt
1 ρ P Ds ρ De P Dρ Tds = de + Pd → ρds = de − dρ → ρ = − T ρT Dt T Dt ρT Dt ρ
t.me/exergy_destruction
S g =
1 1 ρ De P Dρ .q − 2 q.T + − T T T Dt ρT Dt ρ
S g =
De = −.q − P ( .V ) + μΦ Dt
1 1 1 P μ P Dρ .q − 2 q.T − .q − ( .V ) + Φ − T T T T T ρT Dt
1 μ P Dρ S g = − 2 q.T + Φ − + ρ . V ( ) T T ρT Dt
t.me/exergy_destruction
1 μ S g = − 2 q.T + Φ T T
1 μ q =− K T K μ 2 S g = − 2 q.T + Φ → S g = 2 ( T ) + Φ T T isotropic T T 2 2 2 2 2 u v K T T μ u v S g = 2 + 2 + + + + T x y T x y y x
Thank You t.me/exergy_destruction