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#178 - 09/14/00 12:10 AM WRC297
piya_k Offline
Member

Registered: 06/19/00
Posts: 5
Loc: Bangkok
I have apply WRC297 to use with cylinder to cylinder intersections but Caesar not allow because Outside diameter of nozzle is bigger than Radius of Vessel . Can anybody explain me about that error.


Piya K.
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Piya K.

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#179 - 09/15/00 10:26 AM Re: WRC297
Jim Wilcox Offline
Member

Registered: 12/20/99
Posts: 46
Loc: Calgary, AB, Canada
WRC 297 is limited to the following conditions:
d/D < 0.5
d/t > 20
20 < D/T < 2500
d/T > 5
Where:
d = nozzle OD
D = mean Dia. of vessel
t = nozzle thickness
T = vessel thickness
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#180 - 09/15/00 11:31 AM Re: WRC297
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 6045
Loc: Houston, Texas, USA
The WRC-297 Bulletin, in Section 3.2 states "Although the shallow-shell solutions used by Steele may be valid up to a d/D ration of 0.5, the exact limit of application depends on the D/T ratio."

So, the nozzle flexibility computation in CAESAR II limits the diameter ratio to 0.5. Exceeding this generates an error message.

This has been further substantiated by the PVRC's recent work "Nozzle - Attachment Design Analysis: ASME Code and WRC Bulletins 107, 297, 368". This document lists the following limitations on WRC-297:

  • Based on shallow thin Shell Theory, by Prof. Steele
  • Nozzle axis is normal to the vessel.
  • d/t >= 20 (However reasonable results are obtained for any d/t)
  • 20 <= D/T <= 2500
  • d/T >= 5
  • d/D <= 0.5 (Depends on D/T ratio).
  • Nozzle-Shell junction ust be a distance > 2*SQRT(DT) on the vessle and > 2*SQRT(dt) on the nozzle away from a structural discontinuity.
  • Note, although the above limits are stated in the bulletin, recent work indicates that the results may be in question when the diameter ratio exceeds approximately 1/3.


So, we will be adding a new warning to CAESAR II if the d/D ratio exceeds 0.333.


------------------
Regards,
Richard Ay (COADE, Inc.)



[This message has been edited by rich_ay (edited September 15, 2000).]
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Richard Ay

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