Heat Exchanger / Rod baffle design

[Nicolasetirex]

Hello,

To design our tubular heat-exchanger we use a HTFS software. However, we have some concern on the obtained results with a rod baffles design which are not coherent.
The software use a correlation from Phillips Petroleum compagny.
I would like to check this calculation on an excel file however despite of my serch, I don't manage to find the relevant thermal equation to calculate heat exchanged within shell.

If you have information on this subject it would be helpful.

Thank you in advance.

Nicolas

 

[unclesyd]

Here is all the information I have on the Rod Baffle design. Phillips did have design program for their design.

I Would also contact the software maker and discuss the problem with them .

http://usuarios.lycos.es/lhva/Rod_baffle_Phillips.pdf

 

[jcazenave]

The latest version of HTFS now call Aspen SHell & Tube exchanger does support single and 2 phases calculation for Rod Baffle.

As Unclesyd said, if you have any question do not hesitate to contact Aspentech support, they should have your answer.

 

[MrBTU]

Rod baffles are essentially "no baffles", they are only there to support the tube bundle and not to direct the shellside fluid. The benefit is low pressure drop, but the danger is maldistribution. You must take care of the distribution in your design - by putting nozzles on opposite sides of the shell (one up one down, for instance). The flow is directly countercurrent, but the velocities (and pressure drops) are usually low. What kind of strange results are you seeing?
Another option if you are fighting pressure drop is to use double segmental or no-tube-in-window design.

 

[srfish]

Other sources of information are:
1. The big thick Heat Exchanger Design Handbook that has a chapter on longitudinal flow.
2. Articles by Gentry and Small from various symposiums and conferences in the early eighties.