f. Nozzle Piping Components - Modeling Approaches, Tips, Techniques used in AutoPIPE

Applies To
Version(s):2004, XM, & V8i
Environment: N/A
Area: Modeling
Original Author:Bentley Technical Support Group

Attention: Please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Modeling Approaches> Modeling Approaches>

This help has been provided in order to give users ideas for modeling typical piping arrangements. The steps shown in each example should not be taken as the only method available to create models. In addition, the intent of the examples is to present ways to create adequate models of specific piping components for analytical purposes.

          Anchors        Bends
          Cuts              Flexible Joints
          Frames         Hangers
          Nozzles        Pipes
          Reducers      Rotating Equipment
          Supports       Tees
          Valves           Vessels

Questions and Answer:

Item #1:

Modeling a Nozzle per WRC 297?

Answer: The following fields of data are available when WRC 297 is selected as a Flexibility Method on a nozzle dialog screen:

Enter in values for L1, L2, and Direction of vessel axis to calculate the nozzle flexibility.

Copied from the On-line help:

L1 = distance from the center of the nozzle to either vessel end or to the face of the nearest internal stiffening attachment (e.g., ring).

L2 = Enter the distance to the other end of the vessel (or nearest internal stiffening attachment in that direction).

Meaning, measuring from the center of the nozzle in one direction along the axis of the vessel to a point where the vessel end or vessel internal stiffener ring, enter the value as L1. Repeat the same measurment in the opposite direction along the vessel to a point where the vessel ends or vessel internal stiffener ring, enter the value as L2 (note, L1 and L2 are interchangeable values with regards to the nozzle flexibility calculation, see online help "Nozzle Flexibility Calculations" for complete details). 

Note: When looking at the Nozzle Stiffness values on the dialog screen be sure to read the dialog text "Nozzle stiffness (E6):". The (E6)  means that the value in the fields below are multiplied by E6, with the given units.

Example, on the dialog screen Rad = 3.1223 lb /in, but in the output report it is printed as Krad=3122285.75 lb/in. Both values and units are correctly printed.

Item #2:

Questions: Can you provide more details on the Nozzle dialog fields, Length and Thcikness?

Answer: From AutoPIPE online help:


Enter the length of the vessel shell wall. Nozzle length is not used in calculated the nozzle flexibility (which is really the vessel shell flexibility). The length defines a flexible joint to which the nozzle flexibilities (as calculated by AutoPIPE) are assigned.

Vessel Radius/ Thickness:

Enter the outside radius (or half the actual diameter) of the vessel and the thickness of the vessel wall in these two fields.

For new user, there remains a lot of confusion around the Nozzle dialog entries for Thickness and Length. Simply put a nozzle element is modeled as a Flexible joint, as shown in the image below.

The Nozzle Length field specifies to the program how long the flexible joint to be modeled will be (distance between A03 - A04).

The Thickness value is used by the program in calculations to produce the respective nozzel stiffness values that will become input into the modeled flexible joint.

Again, Length and Thickness are 2 different fields used for 2 different reasons; one modeling and the other calculations.

Under most circumstances Length & Thickness will be the same. However, be carefull when entering these values, always look to see what units are being used. In English units, Length is entered in FT (mm), where Thickness is entered in INCH (mm).




See Also

Bentley AutoPIPE

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

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