My query is about the calculation of hillside nozzles. When i run the PV analysis, my lateral hillside nozzles come up in orange colour concerning with the below warning. Meanwhile, i have been giving external loads to check these nozzles based on WRC 107 calculation method.
Does anyone know how to sort this warning out?

Warning:
The equations for nozzle local stress analysis pertain to radial nozzles only
and this nozzle is not specified as radial. Please check the specific
analysis code for all assumptions and limitations.

Hi Ramil,

The research and work done by the WRC in the 1960's and later in the 70's only addresses radial nozzles located in cylinders and spheres. The local stress analysis of a hillside nozzle will be different than a radial nozzle. So you would not expect to obtain the same answer.

So as a result, PV Elite issues the warning to let you know this. The WRC analysis in PV Elite is performed as if it was a radial nozzle. If the nozzle is highly loaded or there is any concern about the analysis, you should look into a more sophisticated approach to solve the problem, like FEA.

My calculated stress ratio for hillside nozzle emerges as shown below:

Vessel at nozzle edge: Max calculated stress ratio= 0.303
Vessel at PAD edge: Max calculated stress ratio= 0.387

As such these stress ratios have been calculated by WRC 107 method and it seems that they are below than allowable limit.

So can i say my nozzles are ok in spite of having warning as mentioned above?

Cheers

Hi Scot,

Could you reply to my above mentioned question which i have got ongoing project?

Your prompt respond is appreciated!

Hi Ramil,

Unfortunately, I cannot give you a blanket yes or no to your question. This is really what I would consider a consulting type of question and I can of course only state my opinion here.

Depending on a number of variables, the actual stress will deviate from the baseline 90 degree case as you would expect. One obvious variable would be the severity of the angle between the nozzle centerline and the shell/head surface and another would be the thickness ratio between the two. To get a really good feel for this, you would need perform a lot of FEA and study how the results vary with the angle between the shell and head. This sounds like a good topic for a research paper. I am almost sure someone out there must have done this.

In in the industry, my guess would be that with a sufficiently low stress ratio of your determination, you would be OK. I would of course urge you to consult with your peers on the subject, gather all the information you can and make your best decision.