temp at outlet

[abdutt77]

Hello all,

I have a pipe of 6 " dia of steel (6 mm thickness). Through which hot gas flow at a velocity of 6.3 m/s. The outside of the pipe is ambient (25 Deg C). Temperature at the inlet of the pipe is 210 deg C. How can I calculate the temperature at the outlet of the pipe (consider the pipe of staight length = 5 mts.).

Abhi

 

[TD2K]

This sounds like a home work question.

You need the mass flow of gas inside the pipe to calculate the inside film coefficient. You need to calculate the outside film coefficient and from those two values (plus the resistance of the pipe wall and insulation, if any), you can estimate the amount of heat loss. With the heat loss, you have a dT on the gas side as it's the source of the heat losses.

 

[abdutt77]

Hi TD2K,

can you please help me with the appropriate formulas ?
I think velocity of gas * Density of gas * cross section area will give the Mass flow rate of gas. Can you tell em the formulas for inside and outside film coefficient.
I dont have any insulation in my pipe. We can nglect the pipe wall resistance. But, from inside and outside film coeffcient, hiw can i calculate the total heat loss.
Pls give the formuals.

In case u require: my ID is foodbiochemabhi@yahoo.com

Thanks in advance

Abhi

 

[SeanB]

You should be able to find the appropriate equations in any Heat Transfer Text Book.

 

[Ashereng]

Abhi,

Is this a homework question?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[abdutt77]

Hi all,

This is not a homework question. My friend is designing some exptl. set-up with these data (?); and he asked me the problem. Together, we started to think and worse we do not have any Heat Transfer book in our lab to refer to. One was there, but is missing now !!
So, I decided to ask in Forum. That's the reason why I asked for the formulae - I cant refer anything presently.

Thx anyway...

Abhi

 

[Ashereng]

If it is a experimental set up, I would suggest you measure the outlet temperature.

Real data is always preferable over theoretical ones in my books.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[25362]

IMO Ashereng is right about the laboratory experiment. In particular since the (unknown) hot gas would apparently cross the pipe length in less than a second, and the steady state formul[æ] you are after may then be quite inaccurate.