Nozzle position (tubeside) in condenser with 8 passes vertical H bundle layout 1

[imatasb]

Good afternoon colleagues,

I am currently designing a condenser that will complement a current aero condenser.
The new condenser is going to be an AES type with 8 passes on tubeside (cooling water), 131 tubes, H bundle layout and a 45º rotated square pattern (company standard for condensation applications).
Due to the fact that vertical baffles will be used, if the bundle orientation is horizontal there will be a lot of by-passing areas around the tubes that will require a lot of sealing strips as shown in this diagram (horizontal bundle layout).

For this reason, I prefer the vertical bundle layout which gives me the best results in my simulations.

However, for an 8-passes H type (mixed) bundle layout the nozzles for the inlet and outlet on the tube side should be on the sides of the distributor (not possible to do 8 passes with this layout entering on top) and not on the vertical I had always specified in my previous designs.

Has anyone used a configuration like the one I am thinking of? I really haven't seen any HX with side nozzles previously but thinking about it no problems come to my mind.

Cheers

 

[Christine74]

First, note that if this is a pure substance that you're condensing, there's no need for seal strips to prevent bypass since the condensation would be (nearly) isothermal.

Second, it's not practical to install seal strips in the middle of the tube bundle, they're normally just used around the perimeter. Normally dummy tubes are used to block F-stream bypass as they are much easier to install.

Third, the tube layout you're proposing would require the channel nozzles to be placed on either side of the channel (either horizontal or "hillside" vertical) rather than at the top and bottom positions. If you don't have nozzles at the top and the bottom you can't fully vent and drain the channel so you'd need to add vent and drain nozzles.

Fourth, because of the proposed pass partition arrangement, even if you did add vent and drain nozzles you'll still have issues draining the tube-side of the exchanger. At a minimum you'd need to drill holes in some of the pass plates, which would cause some tube-side bypass.


-Christine

 

[Christine74]

Also note that the bypass you're talking about would only occur in the middle three tube rows, so the effects are limited and it wouldn't have much of an impact on the thermal design in any case.

That said, it might be possible to place the channel nozzles on the top and bottom and use internal elbowed piping to direct the flow into the first and last tube passes.

-Christine.