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Control Valve Sizing For 2-Phase Flow

control valve two phase flow pressure relief cv flow coefficient sizing for 2-phase

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#1 Boltgun

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Posted 07 November 2019 - 03:40 AM

Hi, 

 

I understand that the subject on Control Valve sizing for 2-phase flow has been discussed several times by the community on this forum. However, what I could not make a clear sense of, on the matter is 

listed as follows:

 

1. Addition, HEM-DS (modified expansion factor, Deiner and Schmidt, 2005) and Warren's Controls 2-Phase Cv Equation (https://tinyurl.com/y6rz4nw3)

 

2. The credibility of the addition model with valve characteristics, i.e., equal percentage and linear.

 

Pertaining to the second point, addition model may be suitable for linear valve characteristics (clarification appreciated) however can't be employed for equal percentage (non-linear variation of % Cv design with opening). 

 

May I know the applicability and the boundary of the applicability for addition model to the 2-phase system I am considering? 

 

The two phase system I am dealing with is liquid (assuming crude oil instead of crude oil+water) and gas (associated hydrocarbon vapors). 

 

 

 

  



#2 breizh

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Posted 07 November 2019 - 05:03 AM

https://www.cheresou...-control-valve/

 

Let you download Norriseal software , they have application for your fluids (2 phases ).

Hope this is helping you 

Breizh



#3 PaoloPemi

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Posted 07 November 2019 - 11:51 AM

Boltgun,

I am familiar with HNE-DS model proposed by Ralf Diener & J├╝rgen Schmid , that method is an extension of omega method proposed by Joseph C. Leung, quite different from the simplified formulation provided in your link,

HNE-DS (as several other models) has been included in my copy of Prode Properties, according my experience the main limit of these models is that they require specific parameters which are not easy to evaluate...

anyway, yes, HNE-DS allows to model flashing liquids.



#4 Boltgun

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Posted 12 November 2019 - 10:59 PM

Appreciate the answers. Thank you.

 

Would you say, as a preliminary sizing for a check case (not a design case), one is allowed to use the addition model, i.e., Cv,gas + Cv,liquid = Cv,valve, for an equal percentage valve characteristic for a specified design Cv?

 

I have concerns where for both cases (assuming 100% valve opening, i.e., calculated Cv should be design equal to Cv), the % opening will not correspond to 100% because of the non-linearity of the %opening vs. %Cv for the said valve.

 

EX: Design Cv = 420. Cv,gas = 225, Cv,liquid = 175, % Opening is below 100%.

 

In this case, should I completely rule out the addition model?

 

Please advice if there is more explanation on the addition model.

 

Best wishes.



#5 PaoloPemi

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Posted 13 November 2019 - 10:01 AM

Boltgun, additive models (based on about constant liquid + vapor fractions) can help with non flashing mixtures,

for flashing mixtures the mentioned HNE-DS model includes a correction based on amount of vaporizing liquid,

but (as said) the formulation is more complex...



#6 breizh

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Posted 13 November 2019 - 10:26 AM

Hi ,

Attached a copy of Manoseilan Handbook .

Good luck

Breizh

Attached Files






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