fluid flow conditioning - industry measurement group...• aga3 test data has shown them to be have...

Fluid Flow Conditioning

2017

Flow Conditioning

• There is no flow meter on the market that needs flow conditioning.

• All flow meters are effective without any type of flow conditioning.

• APPLICABLE TO ALL LIQUIDS AND GASES

2017

Flow Conditioning

Why do we want to use flow conditioners then?

• Can eliminate up to 80 – 95% of pipeline swirl.

• Attempt to restore flow profile symmetry and eliminate distortions.

• Isolates the flow meter from upstream disturbances.

• Allows much shorter meter runs to be used with much higher repeatability.

• Improves the benefits of many USM diagnostics by providing flow stability.

• Helps with noise or pulsation problems.

• Helps balance the pressure, velocity and flow rate of meter tubes running in parallel.

• They UNLOAD the flow meter, helping it become even more accurate.

2017

What is a Flow Conditioner?

Four general types of flow conditioners 1. Tube bundles – eliminate swirl only – actually lock in distorted velocity profile 2. Perforated plates – reduce swirl and asymmetry – do not produce fully developed flow

profile 3. High performance flow conditioners – eliminate swirl and produce fully developed floe

profile 4. 245D of Straight Pipe

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What is a Flow Conditioner? – Orifice meters

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What is a Flow Conditioner? – Ultrasonic Meter

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Cone Meters, with Swirl

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Even these but don’t tell any one

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Why should we use a Flow Conditioner?

Reduction in straight run upstream lengths required for repeatable measurement

When dealing with flow measurement, we cannot simply stick a flow meter in the pipe, turn it on and expect perfect results.

In the real world, we have to deal with:

• Installation effects – tees, valves, elbows, probes, etc.

• Swirl

• Flow profile distortion

• Pulsation

• Noise

All of these combine in different ways to generate measurement errors!

2017

Why Fully Developed Flow ???

• Fully developed pipeline flow is the ideal state of a fluid in a pipe.

• If we had an infinitely long pipe, this is the flow we would always see.

• It is mathematically predictable.

• It is perfectly symmetrical around the center of the pipe.

• It has no swirl.

• This *should* guarantee us perfect, error free, repeatable measurement.

• Reality is that Installation effects take us away from this state.

2017

How They Work

• Hole pattern is arranged so that the resulting downstream condition is a fully developed profile, the same as would be achieved by a long length of straight, uniform pipe.

• Stream is forced towards the holes in the plate which forces the pressure field to balance immediately upstream of the flow conditioner.

• Stream reaches a max velocity through the holes of roughly 3 times the average upstream pipe velocity.

• Immediately downstream of the flow conditioner (about 1D) the peak velocity is 20% higher than the average.

• By the time you get 2 – 3D away, the flow is fully developed, and your peak velocity at the centre of the pipe is 15% higher than the average pipe velocity,

• If swirl is present, this is cut out by the acceleration of the gas, and the thickness of the plate.

2017

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How They Work - CPA 50E

2017

Fully Developed Flow – Repeatable & Uniform

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Fully Developed Flow

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Installation Effects – Life gets in the way

Every pipe fitting generates an installation effect.

• Tees

• Elbows

• Expanders

• Reducers

• Valves

• Probes

All of these can combine to create a deviation from perfect fully developed flow.

2017

Swirl

• Swirl is the rotation of fluid in a pipe.

• It is caused by any change in piping direction! – Elbow, 45, tee..

• It can also be caused by any partial restriction of a pipe – Probe, filter, change in line size, reducers / expanders…

2017

Swirl

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Dual Elbows In Plane, 1D of Separation Streamlines

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Dual Elbows In Plane, 1D of Separation Velocity Contour, 0D

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Dual Elbows In Plane, 1D of Separation Velocity Contour, 5D

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Installation Effects - Elbows

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Dual Elbows Out Of Plane, 1D of Separation Velocity Contour, 0D

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AGA 3 – Appendix for worst case

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USM’s & Tees – fantastic swirl generator

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Installation Effects – Tees

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Dual Tees In Plane, 1D of Separation Velocity Contour, 0D

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Installation Effects – Valves

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Installation Effects – Reducers

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Installation Effects – Elbows & Orifice Plates

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Measurement Errors – why we do what we do!!

• The further we get from our perfect, swirl free, fully developed flow, the more uncertain our measurement becomes.

• Error due to flow profile distortion – deviation from baseline state.

• Error due to swirl itself.

• What if we want to shorten our meter run?

• What do we do?

• Meter uncertainty statement is going to be formed under the most ideal circumstances that the manufacturer can provide

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Without Flow Conditioning

• We can build a meter run without any sort of flow conditioning!

• It just needs to be very long to compensate for installation effects and swirl.

• AGA3-2000 even allows this.

• Table 2-7 shows suggested meter run lengths when a flow conditioner won’t be used…but the runs could end up being 44D, 95D or even up to 145D long!!

2017

Flow Conditioning

A properly designed Flow Conditioner converts this flow....

...Into this.

2017

Flow Conditioning

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Empty 5&5 OIMLR137 25m 15000 Horizontal 2.5D Upstream Empty 5&5 OIMLR137 25m 15000 Vertical 2.5D Upstream

Empty 5&5 OIMLR137 25m 15000 Horizontal 1D Upstream Empty 5&5 OIMLR137 25m 15000 Vertical 1D Upstream

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Flow Conditioning

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CPA50E 10&10 OIMLR137 25m 11500 Horizontal 5D Downstream CPA50E 10&10 OIMLR137 25m 11500 Vertical 5D Downstream



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Tees – Swirl Removal

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Swirl – ALL SCENARIOS

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Meter Types

• All volumetric flow meters can be flow conditioned: Orifice, Ultrasonic, Venturi, Coriolis Vortex, Turbine, Cone, Mag, etc.

• Every meter type responds differently to the effects of swirl and flow profile distortion.

• Volumetric flow meters are looking for ‘good flow’. Flow with minimal swirl and good flow profiles.

• A flow conditioner is simply trying to improve the flow that the meter is seeing.

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Orifice Meters

• A thin plate with a very sharp chamfered hole creates a significant pressure drop.

• The flow rate of the fluid is proportional to the pressure drop.

• So why is there a problem?

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Orifice Meters

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Orifice Meters with Swirl

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Orifice Meters

Velocity Velocity Swirl P1 P2 Bulk Density K deltaP

(fps) (m/s) (Degrees) (Pa) (Pa) (ρ) (Pa)

50 15.24 0 5598181 5458170 36.84 32.73 140011

50 15.24 20 5591067 5471339 36.74 28.06 119728

50 15.24 45 5560318 5497955 36.68 14.64 62363

• In orifice measurement, swirl can change the pressure differential that is being measured.

2017

Cone Meters

• Similar to other dP devices.

• Have a high pressure and a low pressure tap.

• Has a unique geometry that forces flow to the outside of the pipe.

• High pressure tap is in a similar location as with a orifice plate or venturi, but low pressure tap is in the center of the element geometry.

• Supposed to be highly immune to installation effects and swirl, requires only 0 – 3 upstream pipe diameters and no flow conditioning.

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Cone Meters, with Upstream Disturbances

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Cone Meters, with Swirl

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Turbine Meters

• Turbine meters with nose cones redirect flow towards the outside of the fluid passage.

• This movement amplifies disturbances within the flow profile

• Turbine meters need to see a well flow conditioned bulk fluid flow.

• Asymmetrical or peaky flow profiles will cause the turbine to over register.

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Turbine Meters

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Tube Bundles

From GRI 97/0207

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Tube Bundle Data

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Without Tube Bundles & Straightening Vanes

• Tube bundles can be very problematic in custody transfer applications.

• AGA3 test data has shown them to be have very unpredictable behavior in scenarios with various upstream configurations.

• A low pressure drop combined with a long length (2 – 3D) result in an inability to properly redistribute the flow profile, while locking in distortions.

• Testing has found tube bundles to cause errors in straight pipe baseline scenarios!

• AGA3 itself shows in table 2-8 that there are configurations where a tube bundles cannot even be used!

2017

17D with Tube Bundle

From AGA Report No. 3, 2000 Edition

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Plate Based Isolating Flow Conditioners

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Ultrasonic Meters

• Rely on a noise pulse that is transmitted through the fluid and the flow rate is computed using the transit time.

• Transit time is affected by velocity disturbances within the pipe, slowing or speeding up the pulse.

• Multiple paths help to generate a complete picture of the cross sectional flow within the pipe.

• The meter only knows how long it took for the pulse to travel from point A to point B.

• It cannot guess the state of the flow along the way.

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Ultrasonic Meters

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USM Path Layouts

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Ultrasonic Meters – 4 Path Data

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Pressure Drop

• All fittings, obstructions, even pipe itself has a “k factor”.

• The k factor is the pressure loss coefficient for a particular piece of piping.

• It is experimentally determined using the measured pressure drop.

• K = Pressure loss coefficient.

• ΔP = Pressure drop across a section of pipe or a fitting.

• ρ = Bulk fluid density, kg/m3.

• V = Bulk fluid velocity, m/s.

2

2VkP

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Pressure Drop

• For natural gas applications, most plate flow conditioners have a K factor of approximately 2.

• Tube bundles are closer to 0.75 – 1.5.

• What if we are worried about the pressure drop across the flow conditioner?

2017

Pressure Drop

• The CPA 50E K factor ~ 2.0 (dP same as roughly 277 feet of pipe, 12” ID).

• Long radius Elbow K factor ~ 0.6 – 0.8

• Tee, flowing straight through ~0.5

• Tee, flow turning 90 degrees from inlet to outlet ~ 1.2 – 1.8

• Flow from a inlet header into a meter run ~ 1.0

• Flow from a meter run into an outlet header ~ 0.78

2017

Pressure Drop

• The uni-directional meter run on page 27 of AGA9, excluding the flow conditioner, will have a total K factor of at least 3.0 – 4.0.

• This is ignoring the fittings that would be needed to connect up to the tees.

• Adding two additional tees would nearly double the pressure drop.

• This is assuming fully developed flow. Swirl and profile distortion will change the pressure drop!

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Relative Pressure Drop

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CPA 50E

CPA 65E

Tube Bundle

Transition Flow

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Pressure Drop Calculation Results

Flow

Pipe Inside Pressure Pressure Est Noise Actual Flow Expected Flow Dynamic Reynold's

Conditions

Conditioner Diameter Drop Drop

@ 610 mm Flow Velocity K-Factor Density Viscosity Number

Type (inch) (psi) (kPa) (dB) (m³/hr) (m/s) ( - ) (kg/m³) (Pa·s) ( - )

5, M3/H 50E 2.000 0.06 0.38 N/A 5.00 0.69 2.31 707.7 5.15E-04 4.79E+04

10, M3/H 50E 2.000 0.22 1.51 N/A 10.00 1.37 2.27 707.7 5.15E-04 9.57E+04

25, M3/H 50E 2.000 1.33 9.16 N/A 25.00 3.43 2.20 707.7 5.15E-04 2.39E+05

50, M3/H 50E 2.000 5.20 35.86 N/A 50.00 6.85 2.16 707.7 5.15E-04 4.79E+05

5, M3/H 65E 2.000 0.03 0.21 N/A 5.00 0.69 1.26 707.7 5.15E-04 4.79E+04

10, M3/H 65E 2.000 0.12 0.81 N/A 10.00 1.37 1.23 707.7 5.15E-04 9.57E+04

25, M3/H 65E 2.000 0.71 4.88 N/A 25.00 3.43 1.18 707.7 5.15E-04 2.39E+05

50, M3/H 65E 2.000 2.74 18.90 N/A 50.00 6.85 1.14 707.7 5.15E-04 4.79E+05

5, M3/H

AGA/API/ISO Tube Bundle 2.000 0.04 0.29 N/A 5.00 0.69 1.75 707.7 5.15E-04 4.79E+04

10, M3/H


25, M3/H


50, M3/H


2017

AGA Standards/Meter Run Compliance

• AGA 3 / API 14.3 - Orifice Meter Measurement, Turbine Meter Measurement, USM’s

• Measurement Canada – Daniel

– Savant

– CPA

• 50E

• 55E

• 65E

• IT is the responsibility of the manufacturer to demonstrate their performance and test results to demonstrate compliance

2017

Flow Conditioning

What if we have debris in our pipe?

• The debris has to go somewhere, ignoring the flow conditioner won’t make it disappear.

• Install a filter (or another flow conditioner UPSTREAM of the meter run to catch the debris).

• Without something to catch debris, we risk damaging or destroying any sample probes, thermo wells or any other equipment in the pipe.

• Better hope there isn’t a compressor or turbine downstream somewhere.

• If the gaskets are unraveling, recommend switching to Flexitallic CGI gaskets with an inner ring to keep the windings intact.

2017

Flow Conditioning

What if we have debris in our pipe?

2017

CPA - UPDATE Your Profile !!!!

Measurement Canada – Approved

CPA 55E & 65E

AGA 3 & 9, OIML test Data - Available

2017

CPA Generation II Flow Conditioners

• CPA 55E – Designed for orifice, turbine and USM measurement.

– Has a pressure drop roughly 10% lower than that of the CPA 50E.

– Roughly 30 dB quieter than the CPA 50E at 110 fps

– AGA3-2000 testing data available, 5D/8D meter run, up to 0.75 beta.

– Swirl that makes it through the 50E is reduced by an additional half.

– Tested in 5/5, 3/5 and 3/3 meter run configurations with OIML R137 upstream piping

2017

CPA Generation II Flow Conditioners

• CPA 65E – Designed for liquid and USM applications.

– Has a pressure drop roughly 50% lower than that of the CPA 50E / 55E.

– Roughly 30 dB quieter than the CPA 50E at 110 fps.

– Lower turbulence generation.

– Swirl that makes it through the 50E is reduced by an additional half.

– Tested in 5/5, 3/5 and 3/3 meter run configurations with OIML R137 upstream piping.

2017

CPA Flow Conditioner Sound Levels

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CPA 65E OIML Testing, TCC

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OIML R137 Piping, CPA 65E

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CPA FloCheck – 50E / 55E / 65E

• Tapped flow conditioner

• DP measurement – Diagnostics

– Measurement

• Check measurement

• Flow measurement

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Common Installation types

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CPA once said….

• It’s far easier to measure good flow with a bad meter, than it is… to measure bad flow with a good meter.

www.flowconditioner.com

www.cpacl.ca

Curtis Cowell

[email protected]

1.403.472.7583

mailto:[email protected]

2017

Thank You

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