Hi Every one,

I wish to share our approach on PSV closed system.
We apply force on each leg along the axis of the leg (not at the bend in both directions). PSV relief force is calculated using usual equations and force in each leg is calculated as shown in the attached sketch (Ref. Pipe Stress Engineering by LC Peng).
I would like to have views of you, experienced and learned members of this forum on this.
I think we should also consider the jet reaction force when the flow reached to larger pipe. Should we? or F7 in the attached sketch is sufficient?

Thanks and Regards

M Waheed

Any body there?

I believe your force calculation is valid only when, as Peng puts it, "delta t is smaller than the effective valve opening time t-sub-o".
Also, I would turn those forces (F1, F2, etc.) around if evaluating the first pass of this pressure wave.

Hope we will be able to verify the PSV clearing force history in BOSFLUID essentials coming with Caesar_II_V10.

In this static analysis proposed, DLF was missing. As noted by Dave Sir, direction will be oppisite to flow direction in first pass of pressure wave and Fij max will be F when length of leg is greater than or equal to a*To.

reg,
sam

I agree with Dave and sam regarding the direction of Force which must be opposite during the transient event. Same as the pressure surge wave travelling at the speed of sound the net unbalanced force between elbow-elbow pairs will be higher at long lengths of pipe.