desresonating baffle

[mjvijayan]

Dear all,

Im designing a heat exchanger and it is required to include a desresonating baffle in the heat exchanger. Does anybody know where can I find resources about this desresonating baffle and how does this affect the vibration calculation in a heat exchanger

regards,

vijay

 

[PlantEng]

TEMA heat exchanger manual is a start. There is a little bit of information in Mechanical Design of Process Systems, Gulf Publishing. Basically, they can be two or more sets of rings with rods that run vertically in one direction and horizontally in another. They dampen the vibration the same way that helical vortex strakes do on tall stacks. Most of the time, I let BJAC(ASPEN) do the calculations for the vibrations. Sorry, I don't know specifics about impact on vibrations equations other than these rods bring the turbulence to a level lower than resonant levels of the natural frequency of the tubes. The equations are similar to vortex shedding equations for tanks.

 

[bvi]

Baffles are included to shorten the effective length of tubes (increasing the tube natural frequency to above the expected excitation frequencies,e.g. from vortex shedding, turbulent buffeting, etc) and are also used to change the acoustic natural frequency to avoid acoustic resonance). There is a lot to consider here. Besides TEMA , there is a good WRC bulletin (I don't recall the number) and also good texts (e.g. Blevins), and also commercial heat exchanger design software (e.g. HTRI).