shell and tube geometry 2

[mielke]

is there a standard or rule of thumb for the minimal allowable spacing between the tube OD and the shell ID?

 

[TJOrlowski]

TEMA discusses maximum diametric clearance between baffle/support OD and shell design ID in Section V, RCB-4.3. Approximate outer tube limit can be extrapolated from there. Effects on shell-side local velocities, vibration, and resonance, as well as aggregate pressure drop should be considered when making changes.

As for minimums: remember, once you design it, someone is going to actually have to build it. Keep that in mind when getting aggressive with your OTL vs shell ID.

-TJ Orlowski

 

[bhushan76]

Hi mielke,

What type of exchanger are you dealing with , fixed tubesheet or floating head ?
In case of floating head exchangers floating head flange require large bundle to shell clearance as compared to fixed tubesheet exchangers. This clearance is function of design pressure , greater the design pressure larger is clearance.
If you have access to HTRI design manuals you can look into graph provided therein.

 

[srfish]

Following are some clearances between the tube OD and shell ID. The clearances were copied from a tube count manual. The clearances are for a heat exchanger where the tubesheets are welded to the shell. For example: a BEM type.
Shell ID clearance
6 -12 1/4"
13-24 5/16"
25-33 3/8"
34-47 1/2"

 

[TJOrlowski]

Following are some clearances between the tube OD and shell ID. The clearances were copied from a tube count manual. The clearances are for a heat exchanger where the tubesheets are welded to the shell. For example: a BEM type.Shell ID clearance
6 -12 1/4"
13-24 5/16"
25-33 3/8"
34-47 1/2"

Are these clearances diametric, or radial?

-TJ Orlowski

 

[srfish]

The clearances are radial.

 

[TJOrlowski]

If those are minimum clearances, they seem overly conservative. If they were diametric, they would look more reasonable.

-TJ Orlowski

 

[srfish]

You are right. These big words throw me(haha).