Hi all
I need to know the method of air cooler modelling in CAESAR
please help me.
THANKS
MAHDEE

Hi
pls see attachment

mandee,
Air cooler header box is usually modeled as a rigid element and weight distributed among various bays (For bays, Refer API661 Figure 2) which is also shown by Jozm in his attachment. The header box movement is decided by the air cooler design. If the design is even pass (Inlet and outlet nozzles on same side the tube expansion is not included (as it allowed to expand on the other side) but if the air cooler is odd pass (Inlet nozzle on one side of the header box and outlet nozzle on other side) than the expansion of the tubes should be included at the respective header boxes. The lateral displacement of the header box(perpindicular to tubes) can be taken as 12mm on one side or 6mm on each side (depends on the design). You should refer the vendor drawing for various details.
In Jozm attchment Rz should be included at nodes 1120 & 1020 because the rotation of the header box will not be govern by the piping as the Air cooler is a massive structure. I hope that experts will agree with me.

Hope it will help

Dear friends Jozm and Rajinder Singh

your information was wery helpfull and great.
thank you very much.
MAHDEE

To add to the above comments:

1. Make sure the Pipe Stress Analyst's requirments are included in the Vendor drawings when they come for review. If you want the header boxes to slide perpendicular to the tubes and restraint along the tubes direction, you will have to ask the vendor for it .

Also watch out for Split header box design.

2. You have to take a look at the routing and see whether you require "connectivity" between the header boxes( usually called Thrust blocks) or you can allow the header boxes to slide on low friction slide pads. This is important and missed sometimes.

3. Some companies treat the header boxes as rigid anchors and include flexibility in the connecting piping. What does your company guidelines say?

4. Also do a search in this forum on "Aircooler piping" .There has been a lot of discussion on this topic.