Convection Coefficient
Convection Coefficient
(OP)
I once came across a useful equation for estimating the convection coefficient for calculating convective heat transfer from the combustion gases to the surroundings (i.e., piston and bore) in a diesel engine. The equation was of the form:
h = C*b^(m-1)*P^m*w^m*T^(0.75-1.62*m)
where
h is the convection coefficient
b is the bore diameter
P is pressure
w is the mean gas velocity (estimated as mean piston velocity)
T is temperature
C and m are constants
The reference also claimed that the overall heat transfer was 65% convection, 35% radiation.
I have used this equation and relation several times over the last two years with relatively good success. The embarassing thing is I can't find or remember where this equation and relation came from. Is anyone familiar with the above equation, and if so, could you provide the reference it comes from?
Thanks,
Haf
h = C*b^(m-1)*P^m*w^m*T^(0.75-1.62*m)
where
h is the convection coefficient
b is the bore diameter
P is pressure
w is the mean gas velocity (estimated as mean piston velocity)
T is temperature
C and m are constants
The reference also claimed that the overall heat transfer was 65% convection, 35% radiation.
I have used this equation and relation several times over the last two years with relatively good success. The embarassing thing is I can't find or remember where this equation and relation came from. Is anyone familiar with the above equation, and if so, could you provide the reference it comes from?
Thanks,
Haf
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RE: Convection Coefficient
RE: Convection Coefficient
Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)
RE: Convection Coefficient
RE: Convection Coefficient
Windsor, If I understood what you are asking, yes there are variations. Actually there are many equations adopted over the years which desrcibe heat transfer in the combustion chamber. Most of Internal combustion engines books, have a chapter about heat transfer. In the same book you can find a lot more of information.