Oil Cooling

[TeeAr]

Hello

Hope somebody could give me an good piece of advice.
Following is the topic.
I have to design an heat exchanger to cool oil temperature.
My problem is choosing which correlation utilizing for calculating pressure drop and convective heat transfer coefficient.
Because of large viscosity variation with temperature I suppose I can’t utilize traditional correlations utilized for water.
Please, which is your experience ? Would you be so kind and recommending me some reference literature where I can find an example of calculation ?

Many thanks

 

[pmover]

reference literature . . .

try:

http://web.mit.edu/lienhard/

http://www/ahtt.html

i highly recommend contacting a heat exchanger mfg for further guidance.

if the inlet/outlet conditions and fluids for both streams are known, then the heat exchanger mfg can conduct the analysis and design for you. something to ponder . . . why re-invent the wheel yourself?

hope this helps.
-pmover

 

[ione]

You can try Sieder-Tate correlation which is described in the attached paper, anyway be aware that for those fluids exhibiting properties with a high sensitivity to temperature variation, the best approach is the numerical one.

 

[tesser]

You can find various correlations at:

http://www.cheresources.com/convection.shtml

Also you will possibly find some useful information at:

http://www.cheresources.com

The correlation references came from this site

 

[SNORGY]

How accurate do you want to be and what is the nature of the oil?

If you are cooling the oil, then the oil is, presuambly, warm or hot. Therefore, the viscosity will be "low" (sort of). If it is not a multi-component blend or a crude oil, but rather, is something like an SAE oil, it can probably be thought of as a Newtonian fluid. For those fluids, I have had pretty good success with the DeGuzman-Andrade correlation for viscosity:

m = A x e^(B/T)

Pick two temperature-viscosity points, take logs on both sides, solve the simultaneous equations for A and B, and you might be close enough to what you need.

Regards,

SNORGY.

 

[TeeAr]

Hello, many thanks to everybody.
Mr Snorgy, indeed I was looking for a correlation for calculating heat transfer coefficient your rule is extremely helpful.
Please, which is the unit of temperature ? C ? K ?

Many thanks

 

[SNORGY]

The units are Kelvin.

You are very welcome.

Regards,

SNORGY.

 

[ione]

TeeAr,

You could try the attached spreadsheet (downloaded from

http://www.xlrotor.com/index.shtml).

It shows several oil type's properties vs temperature

 

[TeeAr]

Many thanks to everybody
Wish you a wonderful 2011