12 replies to this topic

[jprocess]

Dear All,
I need information about typical method for 2 phase flow line sizing and important points that i should consider.
Thanks in advance.
Best Regards.

[pleckner]

This has been discussed before in multiple posts in both this section (Industrial Professionals) and the Student section.

Saying this (and you should look these up for a number of opinions), I always recommend the aritlce by J.Leung, "Easily Size Relief Devices and Piping for Two-Phase Flow", J. Leung, CEP, December 1996

I feel this article should be the bible for two-phase flow, or at least the starting point. You can also look at API RP520, 7th edition where they discuss this in Appendix D. If you read the article I reference above you will notice something familiar with what is in API RP520 as API RP520 basically adapted the information from that article. By the way, the procedure comes from DIERS.

Point of note: The procedure from DIERS is based on a thermodynamic analysis of a two-phase flowing system (and verified in tests). Other procedures you will find are purely empirical and thus have no real good engineering basis other than they've been tested on limited systems and have been around for sometime.

[Radionise]

Get, Crane Technical Paper No. 410 "Flow of Fluids Through Valves, Fittings, and Pipe". The book is highly recommended.

[Dtan76]

Hi Jrprocess

I guess you are Malaysian right? If you need a copy of Crane Technical 410 just drop me a email add. then I should sent you a copy

Or you want a spreadsheet for 2 phase flow line sizing also?

Regards
DTan

[jprocess]

Dear Sir,
Thanks a lot for your reply.
I should be grateful if you would send me a copy of Crane Technical and also that spreadsheet.
But you did not mention your e-mail address.
Thanks in advance.
Best Regards.

[gvdlans]

Crane Technical Paper 410 can be purchased for only $36.= via http://www.tp410.com/tp410.htm. They also provide software via this website.

Note that sending copies of this document (e.g. via e-mail) is a violation of copyright laws. In other words: it is illegal.

[pleckner]

CRANE will not give you the procedure for two-phase flow (at least not the hard copy; not sure about the software).

I strongly suggest you look at Leung's procedure for two-phase flow. It is based on DIERS technology, has a thermodynamic basis rather than being empirical and it has been adopted by API. It really is the place you should start.

And I have to second "gvdlans" unless of course this is a legitimate spare copy he has and not just reproduced.

[gvdlans]

From the information on the above mentioned website I get the impression that the CRANE software is based on Darcy-Weisbach equation. This is suitable for liquids and to some extent for gases (provided that pressure drop is less than 10-40% of inlet pressure). It is not suitable for 2 phase flow. See the explanation on http://www.flowofflu...com/faqcomp.htm

[Dtan76]

Dear all

I must apologized in here. The proper way to obtain a soft or hardcopy of Crane Tech 410 is purchase the original copy from Amazon.com or other trusted sources (vice versa). I have the hard copy (metric eddition) but I must not allow to download in here. I clarified my previous statement and hope other member in Cheresources do not ask me favor to send them the hardcopy.

Regarding the 2 phase spreadsheet, please find here:

Regards

[Profe]

Hi .................

For increase your knowledge, attached I send an article in PDF file with theory about two phase flow used in the worksheet sent before by Dtan76:

In this file you additionally find a lot of references about this interesting subject.


Good luck.

[Art Montemayor]

All:

The referenced article is a good one. However, it contains a major flaw. If you read the article carefully you will become aware that there is something missing: the publisher left out a Figure out of the article – the one pertaining to coefficients relating the type of flow-pattern. For example, they illustrate the 7 types of 2-phase flow in Figure 1. But then they cite that “to determine which type of flow exists, use the following coefficients in Figure 1, which is a flow-pattern plot”. There is only one Figure 1 and no flow-pattern plot is furnished.

I recently contacted the author, Steve Chafin, and he was very cordial and helpful in confirming the above. He wrote:

"I believe that the flow pattern plot that was left out of the article is Figure 3 in Baker, O&GJ, July 26, 1954. That plot is widely recognizable and used frequently in referencing flow regimes. There are others, but many people reference this one. Hopefully, the article references include the citation for the Baker article in Oil & Gas Journal. I do not think I have a better copy myself than the O&GJ article.

Hopefully, you recognize the "disconnect" between the two phase flow predictions and the flow regimes that would be provided by the Baker plot. That is, the pressure drop calculations in the article proceed without need for referencing the Baker plot. All of the calculation methods are wholly empirically based without specific reference to flow regime. Of course, it is always useful when dealing with two phase flow to have an idea of the flow regime you are dealing with!

Note that it is possible approach the solution to two phase pressure drop relative to specific flow regimes. I have previously written two phase pressure drop calculations that are flow regime specific. To be fully honest though, the accuracy of the results from the article match (given the wide range of accuracy of the methods) that of those calculated from the specific flow regimes in my opinion."

If anyone has a copy of the Ovid Baker, Oil & Gas Journal, July 26, 1954 article, could you share a copy with me?

Thanks,

Art Montemayor

[joerd]

A copy of the graph is in Perry. In my copy, 6th ed., it is Fig 5-48 on page 5-41, Fluid and particle mechanics, Two Phase Flow chapter.

[Profe]

Hi all.

Thanks a lot for the positive observations. But thanks again for the post sent by Joerd, attached you find two copies of the graph Flow-pattern regions in cocurrent liquid/gas flow through horizontal pipes, and Flow-pattern regions in cocurrent liquid/gas flow in upflow through vertical pipes. Source: Perry & Green. Chemical Engineers' Handbook. 1999. McGraw Hill Co. Chapter 6. p 6.26 and 6.28


Best regards