Thanks so much for the suggestions. I used the downstream pressure and the pressure drop is 12 psi now. Can this 12 psi be considered as the backpressure to the valve? What would be my upstream pressure, 235 or 26 psi? 12 psi sounds much better than 0.7 psi. But does it make sense for 350...
Thank you all for the advices. The equation I used is the simplified form for isothermal compressible gas flow. Both Crane book and Perry book has similar equations. I used 200 psi as the upstream pressure and I only got a pressure drop of 0.7 psi. However, the Darcy equation gives about 150...
Latexman - thank you for your reply. I calculated the pressure drop through the discharge line use simplified equation for gas flow,
P1^2-P2^2=25.2*(S*Q^2*Z*T*f*L)/D^5.
p1: upstream pressure psia
P2: downstream pressure psia
S: Specific gravity
Q: gas flow MMSCFD
Z: compressibility factor
T...
I am new to the pressure relief valve world and having an issue on a relief valve that has already been installed. The valve is a conventional relief valve for pipe thermal relief of vapor and the outlet is piped to a vent. The capacity of installed valve is about 4 times of the flow rate...
The equation in compress is
fc = Cc / (((tc - ts) + n*ts)*(d / 2)*K2)
However, in the referred book is
fc = Cc / ((ts + n*tc)*(d / 2)*K2)
Thank you,
Arbor
I noticed that the equation for foundation bearing stress calculation for the skirt base ring design is different from the referenced book by Jawad & Farr. Is this an error or there is some reason behind the change? Thank you,
TGS4, thank you for a very clear procedure for using Part 5 of Div.2. I still have a couple of things unclear.
1. The buckling approach in Part 5 still does not cover my original questions. It has the minimum design factors for shell under axial compression and under external pressure...
TGS4, thank you for your explanation. First I need to apologize that I didn't give enough background of my analysis and mixed all my questions together. The stress analysis is for a pressure vessel designed to Div.1. FEA is mainly used for the local stresses. Section II Part D allowable stress...
Thank you all for the valuable comments. I have learned a lot from this forum.
Regarding the local area in the circumferential direction, it was from the stress analysis for nozzle loads or localized loads. Depends on the geometry and loads, there could be a relatively large area in the...
I am working on a stress analysis for a leg supported vessel with vacuum and seismic load. Due to the vacuum and the bending moment resulted from the seismic load, the area above the leg sees axial and hoop compressive stress. I am having a hard time for the buckling check and I hope I can get...
I am trying to use Compress nozzle FEA for nozzle analysis. The nozzle loads are given as due to weight, thermal, and seismic.
In compress nozzle FEA, there are input conditions for weight, operating, occasional and thermal.
My understanding is that nozzle loads due to weight will be input...
johnhors,
You are right about my model and the eigenvalues. I have several approaches to check different failure modes of a pressure vessel based on ASME code. The approaches include linear elastic and non-linear plastic analysis. The code also requires to check buckling when there is...
johnhors,
I am trying to model the buckling of a pressure vessel head knuckle under internal pressure (there will be tangential compressive stress in the knuckle due to internal pressure). However, the model kept giving me negative values for the shell and head buckling which would be due to...
hi bassmanjax,
I am interested in positive eigenvalues only in my analysis. However the analysis hasn't been able to give me the first positive eigenvalue after many negative values. I don't know how long it needs to run to find the positive value. Is there anyway to get positive eigenvalues...
