2 replies to this topic

[Nazgul]

Hi guys!
First of all, sorry for my poor english
I'm a european university final-year student (Power Electric Engineering) working on a thesis that involve some sheel and tubes heat exchangers.
My question is:
How the overall heat transfert coefficient modify when the pressure increase?
For example if i have water on cold side operation at 85°C (pressure 3 bar) and water at 310°C (pressure 104 bar) on hot side operation, can i use the values reported here: http://www.cheresour...xchangers.shtml ???
Please help me,i'm really on trouble
Thank you!

Frank

[djack77494]

Frank,
Pressure by itself does not impact the heat transfer coeficient. Pressure changes other physical properties of the fluid(s) which DO impact heat transfer. The effect would be very, very small in a (nearly) incompressible liquid such as water even though it could be quite significant for gases and vapors.

In your case, I would venture to say the impact is probably negligable. Pressure changes will not impact the density, viscosity, thermal conductivity, or other pertinent physical properties significantly, so I'd forget it.
Doug

[Nazgul]

Thank you Jack!