Equipment nozzle modelling in CAESAR II
Please refer section 6-8 , 6-9, 6-10 and 6-11, 6-12, 6-13 of Caesar
II
application guide. It appears that there are two different methods of
equipment nozzle flange modelling for vertical vessels and horizontal
vessels.
1)vertical vessel and horizontal nozzle flange :- Nozzle neck modelled
as pipe and flange modelled as rigid with weight.
2)Horizontal vessel and vertical nozzle flange :- Nozzle neck modelled
as pipe and flange modelled as rigid with zero weight.
Can anybody throw some light on this modelling please?

Best regards

Mahesh

The flanges are normally modeled with weight. In the horizontal vessel with vertical nozzle flange, the manual states that the flange weight is 250 lb., which is what the weight should be on the rigid element from 26 to 30. Simply a typo in the manual (apparently dating back to the DOS days).

Thank you very much sir.
I would like to get knowledge on some of the following points.
1) In WRC 107, whether the moments and forces are resolved and checked at nozzle/ shell interface or nozzle flange / piping flange interface?
2)In one of our stress systems nozzle is 143 mm thick and is an intgral part of vessel(no welding). should we model the neck as rigid body or as pipe?

Thanks with regards
Mahesh
Ranhill worley Parsons.
Malaysia.

1. WRC 107 was written as an analysis too for shells. Given this, logic would suggest that forces and moments should be calculated as they are applied the shell, not at the nozzle flange face.

2. There are several geometric factors to use when evaluating a nozzle. In addition to wall thickness, it is necessary to know what the OD (or ID) and the length of the nozzle are before deciding how to model them. In your case, for pipe OD's <= 286 mm, I would recommend modeling it as a rigid body. For pipe OD >14300 mm, it would be best to analyze this using softwre other than CAESAR II. For intermediate cases, judgment is required.