What is the link between Reynolds number and heat transfer coef. 1

[editheraven]

For my diploma exam I did my research in a program named HTRI. I have a heat exchanger with hot TAME in the shell and cold water in the tubes. I noticed that the Reynolds number and heat transfer coef graphs have almost the same shape

http://files.engineering.com/getfile.aspx?folder=41b67e83-a438-495e-ba41-5ffef312546d&file=6.jpg

Is there something like a rule or it's just a coincidence?

 

[editheraven]

Sorry the pictures got uploaded wrong. Here they are

http://imgur.com/a/sVoDf

 

[BigInch]

Increasing Rn usually corresponds to increasing mass flow. Heat transfer also increases with mass flow.

You might notice some differences at very low Rn when convection heat transfer becomes more dominate than conduction heat transfer.

you must get smarter than the software you're using.

 

[dcasto]

Normally the higher the turbulence, the better the heat transfer coefficient. Look up a heat exchanger "turbulator"

 

[editheraven]

Thanks for your answers. They really helped me.

 

[moltenmetal]

In turbulent flow, film coefficients vary as Re^0.8. In laminar flow, what it works out to is that you need the same area irrespective of tube diameter. But exchanger performance is complex- there are a lot of factors at play, and what matters most is which resistances to heat transfer are controlling.

 

[processeng2014]

All transfer (heat, mass, momentum) is proportional to turbulence.

 

[25362]

Except, probably, for Braess paradox

 

[MortenA]

Check out the explanation of te Nusselts number

http://en.wikipedia.org/wiki/Nusselt_number