Fin thickness calculation in a plate and fin heat exchanger 1

[vinnuram]

hey all,
I am actually trying to validate the results for a plate and fin heat
exchanger.I am trying to calculate the gas side and air side fin area
and total area.
my question would be
1.how to calculate the fin area and total area.what are the things yo
uconsider when u calculate these.
2.I was wondering whether fin density and fin thicknes are realted to
this calculations.
3.I am actually trying to calculate for a plain fin.I can give the
values so that if you can play around with ur idea.
4.Fin Density=0.615 per mm ; Fin metal Thickness=0.152 mm:hydraulic dia
=0.002383 mm
he gave a direct value for Fin area/total area =0.923
I want to know how he got 0.923
thank you
vinnu

 

[thermcool]

fin density should be enough to provide sufficient surface area for the proper convection while at the same time should allow for gas/air movement through it. In other words, the pressure loss across the fin stack has to be consider while deciding the fin density.

you can calculate the finned plus unfinned area of the external surface ( internal surface)

From you cooling conditions, (flow rate of air for forced convection, hydraulic diameter of flow channel) you can assume the Nusselt number and calculate the maximum heat transfer capacity of the fin stack.

It might sound confusing if you havent gone through this before. try reading about the fin analogy (chapter on extended surfaces ) from any heat transfer book ( Incropera & Dewitt, Holman, etc)

the fin aera/total area is useful in calculating overall surface efficiency of the fin which is useful to calculate the outlet temperature conditions and other flow conditions for the fin array.

if you can provide me complete detailing i may be able to help you further.

 

[thermcool]

There is one very good reference i remember

Fundamentals of Heat Exchanger Design by Shah and Sekulic

This might help you with your design process.