Analysis of Relief Valve Discharge Piping 1

[lcmechengr]

I am looking for procedure to analyze a closed relief valve system. So far, all I have run across are ways to analyze open relief valve systems. I do have access to Caesar II software. Does anyone know of any specific examples? Thanks.

 

[BigInch]

By closed relief system do you mean a relief flow into a pressurized tank, rather than to an open or non-pressurized tank?

I assume you want to do a hydraulic analysis, but Caesar is for stress analysis (?).

http://virtualpipeline.spaces.msn.com

 

[lcmechengr]

BigInch,
I am trying to analyze the dischage piping of relief valve that discharge into systems that floats on atmosphere (typical flare header with KO pot arrangment). When I speak of analysis, I am needing to perform stress analysis that takes into consideration the impulse forces of a relief valve opening and the associated dynamics.

 

[BigInch]

I would first do the usual relief valve design to get the size, then choose a valve with the necessary characteristics. I would then enter the exact valve parameters in a transient hydraulic analysis program to see if the valves works with the system, its set pressure and any backpressures, as expected and then calculate the unbalanced forces when the valve is opening and flowing. If the unbalanced forces were significant, I would get out a stress analysis program, such as Caeser, to determine the pipe stresses.

As far as I know, there are no programs that will do all the above in one box.

http://virtualpipeline.spaces.msn.com

 

[davefitz]

The hydraulic analysis program would need to be smart enough to determine if choked flow has occurred, and where it has occurred. Some types of outlet silencers do not have choked flow at the outlet, and if the entire exhaust system is sealed, then the only choke point might be the relief valve orifice / throat.

Also, for transient analysis, somehow one needs to determine if chattering is ocurring,, and either that needs to be simulated, or the system modified to avoid chattering.

 

[MJCronin]

Have you talked with these people ?

http://www.sunrise-sys.com

MJC

 

[BigInch]

Pipenet, PipeFlow, Stoner PL Simulator, Pipeline Studio, all handle hydraulics, but ...not stress. No combined program that I know of.

http://virtualpipeline.spaces.msn.com

 

[barqueiroenmarte]

Davefitz,

Any suggestion about software capable of performing such analysis correctly based on your experience? We are thinking of purchasing software for hydraulic transients and would like to perform this kind of calculation.

Thank you for the information.

 

[BigInch]

Stoner Pipeline Simulator and Pipeline Studio will do it. I haven't used any others.

http://virtualpipeline.spaces.msn.com