non TEMA tubular Heat Exchanger

[130684]

Dears,

I have an issue with a tubular heat exchanger which was not designed according to TEMA. I have to perform a checking/rating, but I can't set up the geometry according to the datasheet. The program I would like to use for the calculation is Aspen HTFS (which performs TEMA only design calculations).
It has 2 passes on the shell side, that's mean, according to TEMA that the shell is Type F (2 pass shell with long baffle).
But... on the tube side it has an odd number of passes (7 passes), which, according also to TEMA, it is not possible with an F shell. I was thinking that it looks like an AFL, but I need an odd no. of passes on tubes.

Any idea of how can i set up the geometry? or how can i perform the calculation?

I also attached the DS and dwg. of the HX.

https://rapidshare.com/files/3332794650/dwg.JPG

https://rapidshare.com/files/3001812452/ds.JPG

Thank you.

 

[EnergyMix]

I wasn't able to open your second file (or at least not in a format large enough for my older eyes to read. Please consider using the engineering.com service supported here on Eng-Tips. From your first drawing, I thought I just counted six rows of tubes. Are you sure there are seven?

 

[MortenA]

I was wondering about the same - how would you make the HX in the attached drawing have an even number of tube passes - i mean tube entry is in one end the exit in the other - the tube passes should always be uneven or the "leftmost" head should have both inlet and outlet flanges?

Best regards

Morten

 

[130684]

Dears,

Thank you very much for your interest in trying to help me.

@EnergyMix: I attached again the datasheet. I hope the picture quality is better. The datasheet states there are 7 passes and the drawing also shows an odd no. of passes. Inlet - nozzle N1, left head; Outlet, N2, right end.

@MortenA: Since it's a checking/rating or simulation case (and not a design) I assume I should use exactly the geometry of the vendor and the tube passes to be always uneven (7 passes).

I was thinking to estimate it as an AFL with 6 and 8 passes and for a conservative approach I would use the pressure drop of the 8 passes HX (for 7 it should be lower) and the heat exchanged of the one with 6 passes (it should be a bit higher for 7).

Kind regards,

 

[MortenA]

@130684,

I guess i just cant read the drawing and get to the same configuration as the DS.

 

[EdStainless]

run the calcs with 6 and then 8 passes. You will need to run trials at both the correct mass flow and at the correct velocity and interpolate the results.
You need to run these variations to get the sensitivity.


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Plymouth Tube