Etude de la combustion de gaz de synthèse issus d'un processus de ...

Appendix C -Rivère model
The work of Boust, (2006) also defines the evolution of η based on “fluid” speed seen
by the wall instead of the mean piston speed, as follows:
0.5 0.2
( bV b V )
η = min ' , ''
(C.10)
With b’=5×10 -4 (m/s) -0.5 and b’’= 8×10 -4 (m/s) -0.2 , V is the local speed around 0-25 m/s.
Final formulation
The model of heat losses by conduction can be summarized as follows:
with
( )
Q = h T − T
w g w
tel-00623090, version 1 - 13 Sep 2011
Where:
ρ g , the gases density local
T g the gases local temperature
R = 8.314 J/mol K, ideal gas constant.
M the gases molar mass
T w the local wall temperature,
2 ⎛ R ⎞ ⎛ χ λ ⎞
h = ρg.
Tg
η
π
⎜
M
⎟ + −
⎝ ⎠ ⎜ T T
w w ⎟
⎝ ⎠
χ =0.0318 K 1/2 and λ= 0.37 K material constants
3
2
Engine (Rivère, 2005):
η
engine
= a+ b < Vpiston
>
With a=7×10 -4 , b=7×10 -5 (m/s) -1 , the mean piston speed around 2-10 m/s
Other conditions (Boust, 2006):
0.5 0.2
( bV b V )
η = min ' , ''
With b’=5×10 -4 (m/s) -0.5 and b’’= 8×10 -4 (m/s) -0.2 , V is the local speed around 0-25 m/s.
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