I have wanted to try the software; however, we do not have a machine in our office with the Linux operating system installed. If any of you have Linux, please give the software a try and let us know how it works. This might be a free solution for sailoday28.
Also they have a free book; “Fundamentals of Compressible Flow” that gives an example calculation set in chapter 8, “Fanno Flow” that may be helpful for validation of the software.
On the negative side, I doubt that there is any significant technical support. But it is free.
BigInch-Maybe the firms are overloaded or not hungry for business.
Zapster-Thanks for your input. I don't have access to Linux. Note: Fanno is for adiabatic flow with friction and not for validation of transients.
I assume there are other programs that are capable, but I have no experience with them. I know with SPS you simulate a complete instantaneous break by flowing to a 0 pressure sink set up at the break point of interest. You'd give the pressure setting an instantaneous flip from normal operating QPT at that point to 0. It would give you the QPT histograms (or pretty much any variable) from the time of break until the line segment is completely depressurized. SPS is only for pipe line & network design, so it won't do any plume analysis, but you'd have the data to start modeling that if needed.
BigInch-For the case you have suggested, a non-flashing liquid, such as for example, extremely cold water and relatively low initial velocity, exit pressure would be 0 psig.
However---
For liquids, there is a possibility that the fluid will go two phase and even choke. The choke pressure should not be calculated by steady state techniques- but by techniques of the method of characteristics.
For gases that initially choke, the choke presssure should not be calculated as a steady state choke condition-but by techniques of the method of charateristics.
Hopefully vendors would use those techniques.
On a past thread for pipe line break, individuals have recommended using steady state calculations for determining exit pressures during a transient. That type of approach will lead to misleading results.
That's why smarter individuals have used this program extensively. As I've said, or was it implied?, there is no point making simplifications that give you inaccurate results when these tools have been available for nearly 40 years now. SPS does not simply step through steady state solutions. Any oil and gas company will accept it for design and analysis use. It can model column separation and collapse, but will not model two phase flow. There are other programs, but its the only one I've used so far.
It calculates the correct throat pressure. The zero is just so you don't have any back pressure from the external that could possibly affect the throat pressure calculation.
BigInch-if the zero is 0 psig at the exit plane, and the liquid is not hot, flashing should not occur at the exit plane. However if the zero is zero psia at the exit plane, then flashing will occur.
By the zero at the exit plane, I mean zero back pressure.
Please note--If back pressure used is absolute zero,when it should be 0 psig, the results will be wrong or use of that program is not completely understood.
This thread should end, unless someone can provide vendor contacts-in which my original question can be answered.
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