2 phase flow correlation
2 phase flow correlation
(OP)
what's a good flow correlation for 2 phase? beggs/brill?
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RE: 2 phase flow correlation
Best regards
Morten
RE: 2 phase flow correlation
RE: 2 phase flow correlation
RE: 2 phase flow correlation
Multi-phase flow is so replete with random flow-responses to unpredictable events that typically the performance is worse than flipping a coin. Write a program some day to predict the next throw of a pair of six-sided dice. If you do better than the odds in Vegas, then your randomizing algorithm is busted. Same with multi-phase flow, you simply never know when and at what frequency your real flow will move around the flow-regime map.
David
RE: 2 phase flow correlation
- Beggs+Brill
- Dukler constant slip
- Homogeneous (Dukler Case 1) or modified homogeneous
To reduce your risk, I recommend you keep the pressure drop reasonable (1-2 psi/100ft max) and you check critical lines with more than one method.
RE: 2 phase flow correlation
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"Pumping systems account for nearly 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: 2 phase flow correlation
RE: 2 phase flow correlation
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"Pumping systems account for nearly 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: 2 phase flow correlation
- Beggs+Brill
Beggs+Brill was developed for small pipe size water air systems - I dont think thats extremely valid for HC systems.
Regarding the ramdom thing - well at the contrary to Vegas doing a lot of tosses of the coin and then establishing your design margins is not so foolish imho.
Best regards
Morten
RE: 2 phase flow correlation
I agree that we have to design piping for multi-phase flow, we always have. My problem is that we pay a bunch of money for something like OLGA to burn and chug over the problem and then feel like we can reduce safety margins because of our "state of the art" software. I've seen slug catchers eliminated from designs and pigging equipment dropped because the FEA models predicted a slug size that was manageable without slug catchers or pigging. This is a bad use of technology.
Random is still random. The last toss of the dice does not influence the next toss. Duckler and Flannigan are pretty easy to implement and the millions of miles of pipe that have been designed using these "simplistic" approaches are every bit as "valid" as a pipe designed using a mechinistic finite element model, but the report is not nearly as pretty.
David
RE: 2 phase flow correlation
**********************
"Pumping systems account for nearly 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: 2 phase flow correlation
1) The best of two phase flow calculation still always 20% error from the real situation in specified operation range. Then if you have so wide operate envelop error could be 40-60%..
2) Many formular is good only for horizontal pipe not vertical pipe
3) Liquid/Gas ratio & its densidty in each pipe section will change when temperature/pressure change, so if Pi of each section change over 15%, you will get the mess, so try to make section more detail
4) always check /calculate new thermodynamic to create the correct fluid property
5)All commercial software has its own defualt, we must put correlated factor after calculation.
6) slug management require proper flow assurance full scope review a long the field life ( steady,dynamic,corrosion management,etc)
RE: 2 phase flow correlation
Best regards
Morten
RE: 2 phase flow correlation
David
RE: 2 phase flow correlation
But the other extreme (we can have anything without a finger slug catcher) is also wrong imo.
Besides - the question was if B&B was the top of the pops - and i just think that its a thing of the past.
Best regards
Morten
RE: 2 phase flow correlation
If I had a licence for OLGAS2000, I would use it for 2 phase calcs.