5 replies to this topic

[rram]

Hi all,

          I have a difficulty in calculating the internal diameter shell in multipass shell and tube heat exchanger.

 

for square pitch, i used the following formula,

 

(Pitch^2  ) *(Np* Nt )= 1/4 Pi Db^2  (for a square pitch)

 

Np = number of pass

Nt = number of tubes

Db = bundle diameter

 

shell diameter = bundle diameter + (2*diameter of the tube)

 

  Is it correct? and what would be the formula for triangular pitch?

 

thanks in advance,

 

Ram

[Art Montemayor]

Ram:

 

You are a student (I presume), so you are not designing a heat exchanger for subsequent fabrication.  So, please tell us the purpose in determining the ID of the heat exchanger shell?   Also, where did you obtain your equation?  We can't be held for knowing every equation ever printed on this Forum.  You are obligated - as a future engineer - to cite your references.

 

Also, the heat exchanger ID is almost never calculated.  It is given, since almost all heat exchangers are fabricated from existing standard shells (or seamless pipe).   In those instances where the shell is fabricated, the size (or ID) is pre-selected and the baffles and tube supports cut and machined accordingly.  So why are you "calculating" the ID?

[rram]

Indeed I am a student and I required to do for my assignment. And thanks for your suggestions. 

 

Greets

Ram

Edited by rram, 17 November 2013 - 02:38 PM.

[Hamedcheng]

Hi

 

use this book

 

"Heat Exchanger Design, E. A. D. Saunders"

[Shivshankar]

Ram,

 

If you are student then you should know what is Hydraulic diameter for square and triangular and basic geometry then you can calculate yourself the formulas for Square pitch and Triangular pitch. Just take sometime and do calculate and for lifetime there will be no need to ask anyone what is formulas for square and triangular pitch.

Edited by Shivshankar, 18 November 2013 - 04:19 AM.

[rram]

Hi Hamedcheng and Shivshankar,

                                                    Thanks, for the suggestions. @Shivshankar, now I got the answer.