HTRI Baffle design (NTIW and single segmental difference)

[knapee]

Dear Sir/Madam

I tried to used HTRI to simulate the AES horizontal exchanger.
Condition :
1. The shell side inlet condition is vapor(39000kg/hr),
liquid (90000kg/hr) 60 degree C
2. The shell side outlet condition vapor 33000 kg/hr (decrease)
liquid 95000 kg/hr(increase), 40 degree C,
3 The tube side is cooling water 250000kg/hr,
inlet/30 degree C, outlet/40 degree C.

Although this type is phase change problems and no-tube-in-window (NTIW) design may be used
for vibration problems, I tried to rating this exchanger with single segmental
baffles type.

The warning message I got is attached in the mail and almost are Bundle, Shell Entrance vibration problem.


I tried to increase the shell side diameter and baffle spacing but in vain.

Could you please help me this trivial problem?

Thank you so much.

 

[srfish]

Without knowing more details like baffle cut, impingement protection etc. I would take a look at the nozzle sizes. Are they large enough to prevent excessive velocities?

 

[knapee]

I select htri design mode first, and then choose simulation and rating mode.
But in design mode, I didn't choose the shell&tube diameter, crosspass, spacing, tubecount
and baffle cut and only let htri to be chosen the proper number.

Then, the result give me this warning:
Thank you very much.

 

[TJOrlowski]

I'm with srfish. Looks like according to HTRI, your rho problems exist at the nozzles. First try increasing the entrance area below the nozzle to equal or exceed that of the nozzle. Then try increasing the nozzle size. Increasing the tube pitch may also alleviate the problem (if it exists in the cross-flow as well).

FYI, no tubes in window might not address your problem at all. Example: You might have vertical cut baffles (cut parallel to the vertical axis of the shell), and radial nozzles located at, say, 0 and 180 degrees. Your windows would be at 90 and 270 in the example, and do you absolutely zero good (but it will make your unit much less efficient).

-TJ Orlowski