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Choke/Orifice Sizing

Choke/Orifice Sizing

Choke/Orifice Sizing

(OP)
How would i go about selecting the correct choke to create a 600 psi pressure drop with a pump rate of 2 bpm.

The inlet pipe i.d. is 2". Thanks.

RE: Choke/Orifice Sizing

How much is the pressure before the orifice?
Do you mean 2 GPM?
What is the fluid media?

RE: Choke/Orifice Sizing

(OP)
I actually worded that one wrong. Sorry. We will be choked down to 1" from 2" id inlet. I need to figure out what rate to pump to create a 600 psi pressure drop. Thanks for the quick response.

RE: Choke/Orifice Sizing

What are you pumping? oil? water? air?

RE: Choke/Orifice Sizing

(OP)
it is actually a water-based crosslinked fluid. 8.5 pounds/gallon with a viscosity of approximately 300 cent.

RE: Choke/Orifice Sizing

The equation I have for liquid flow through a choke is:

Flow rate = C * Cd * D * Sqrt(Pressure drop/liquid density)

C is a constant depending upon units (bpm, 64ths, psi, ppg etc).
Cd is a choke co-efficent supplied by the manufacturer for different bean sizes & Reynolds number

For a choke to work, the flow through it must must be critical, which is generally taken as Pressure upstream / pressure dopwnstream is greater than about 2.

RE: Choke/Orifice Sizing

BrettARichard,
Be really careful designing anything for pumping a cross-linked gel using the standard correlations.  These corelations are generally based on Newtonian fluids and cross-linked gels rarely have a linear stress vs. strain relationship.  Many of them behave like Bingham plastics (i.e., like toothpaste they behave more like a solid than a liquid until the strain reaches a certain point, then they flow like a Newtonian fluid).

You probably have already thought of all of this, but I just wanted to raise this point.  I've seen several poor-boy frac operations get into trouble when the field guys put in a pipe choke that wasn't in the original design and caused the system to be on the wrong side of some stress-strain curve.

David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Choke/Orifice Sizing

DrillerNic,

Quote:

For a choke to work, the flow through it must must be critical, which is generally taken as Pressure upstream / pressure dopwnstream is greater than about 2.

This sounds like the rule of thumb for a gas or vapor to me.  You may want to re-check this.  The OP is asking about a liquid.

Good luck,
Latexman

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