Re# of 8.8 million, What Nu equation should I use?
Re# of 8.8 million, What Nu equation should I use?
(OP)
I apologize but I am fairly limited with my resources. Basically what I have is Exhaust at 80psi and nearly 7lbm/s at a max temperature of 2000F in a 11" pipe. I know how todo most of the equations but I cannot find a Nu Equation for that type of flow and that high of a reynolds number. I am looking to calculate the heat transfer coef. I used Nud=.023*Red^(4/5)*Pr^n; n=.4 and got h=2.38e3 W/m^2K. That seemed pretty high, so I am going to recheck my calcs. Any insight would be greatly appreciated. I dont have much experience with this so bear with me.





RE: Re# of 8.8 million, What Nu equation should I use?
How are you calculating your reynolds no?
RE: Re# of 8.8 million, What Nu equation should I use?
RE: Re# of 8.8 million, What Nu equation should I use?
Visc. Exh 1.07E-06 lbm/Ft*s
U exh 123.0844865 Ft/s
Here are the values I was using.. If your noticing small discrepencies.. its because I used 80psia, 6.5lbm/s, and D=10.5"... I havn't had a chance to check everything yet, I plan to do it shortly...
Thanks for the help
RE: Re# of 8.8 million, What Nu equation should I use?
At 2000 F, convection is a minor detail more or less. what are you doing?
RE: Re# of 8.8 million, What Nu equation should I use?
RE: Re# of 8.8 million, What Nu equation should I use?
hacksaw
I am looking at installing a cooled probe in the exhaust, its a custom device and I am doing some preliminary work with it. The surrounding pipes are uninsulated if you were wondering. If you were leading to radiation, that is something I have to look at next
RE: Re# of 8.8 million, What Nu equation should I use?
Assuming Pr0.4~0.95, Re~250,000, the thermal conductivity at ~0.15 W/m.K, the dia, 0.267 m, and using your formula
Is this estimated value a more reasonable one ?
RE: Re# of 8.8 million, What Nu equation should I use?