© swagelok company, 2004 cfd-based liquid flow calculations for modular sample systems john j....

© Swagelok Company, 2004

CFD-based Liquid Flow Calculations for Modular Sample Systems

John J. Wawrowski

Swagelok

Solon, Ohio

IFPAC 2004

Arlington, Virginia

January 12-15, 2004


Agenda

Review of Previous Work

Flow Testing Description

Flow Testing Results

Is a larger standard required?

Important Considerations

Conclusions


Previous Work Studied

The flow capacity (Cv) of a three-position Swagelok MPC systemThe effects of using different surface-mount components on the total system CvAn analytical method for predicting the total system Cv The effect of the fluid type on the pressure drop through a substrate flow componentThe pressure required for a liquid sample to flow through a three-position Swagelok MPC system


Previous Work Results

Created and validated a mathematical model for predicting flow capacity of a Swagelok MPC system

The surface-mount component has the largest effect on total system Cv

Developed a valid equation for predicting pressure to drive liquids

Based on kinematic viscosity

MPC requires minimal driving pressure


Previous Work

Check Valve

Cv = 0.9

Toggle Valve

Cv = 0.11Pneumatic

Valve

Cv = 0.07

Filter Metering Valve

Cv = 0.03

Total system Cv: 1/Cvtotal 2 = Σ (1/Cvi)

2

System Cv changes based on surface-mount components


Previous WorkEffects of fluid type on required driving pressure

For liquids with similar kinematic viscosities (υ = μ/ρ):

ΔPfluid / ΔPwater = (1/SGfluid) x (mass flow rate of fluid/mass flow rate of water)2

For liquids with different kinematic viscosity (i.e. motor oil):

ΔPfluid / ΔPwater = (υfluid / υwater).5


Previous WorkPressure drop - 3 position assembly

Media Density(kg/m3)

Kinematic Viscosity

(m2/s)

P(psi)

Air 1.2 1.5 x 10-5 0.003

Ethyl Alcohol 790 1.5 x 10-6 1.14

Benzene 875 6.7 x 10-7 1.22

Ethylene-Glycol 1,111 1.4 x 10-5 2.74

1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

0.1110100

Pressure (psi)

Kin

em

ati

c V

isc

os

ity

(m

2 /s)

Benzene

Ethyl AlcoholGasoline

Water

Ethylene-Glycol

SAE 30 Oil

Lube Oil

Air

Pressure to Drive Liquids300 ml/min through 3-position MPC system


New Testing

Re-tested original three-position system

Nine-position systemStream Selector valve included

Ethylene-Glycol and 10W-30 Oil

Determine pressure required to achieve 300 cc/min

Tested by an independent third party


Nine-Position System


Test Set-up

Pressure regulator

Nitrogen Supply

Head Tank

Calibration fluid Diverter (timing)

Graduated cylinder

FLOW Control valve

Meter Assembly

Sump

DpT P


Preliminary ResultsDrive pressure to achieve 300 cc/min

Ethylene Glycol3-position system: 10 psig

9-position system: 20+ psig

Depending on metering valve position

10W-30 Oil3-position system: 30 psig

9-position system: 40+ psig


New Standard Needed?

Component with the lowest Cv has the greatest affect on the total system Cv

Surface mount components on the market have the same Cv’s as their traditional configurations

Stream Select Valve

Needle Valves

Filters

Check and Relief Valves

0.1 is typical


Important ConsiderationsRegardless of the size of the flow passages, all sample systems will eventually need to be maintained

PluggingCorrosionLeakage

You should choose a substrate design that facilitates fast, easy maintenance or expansion

Replace or add components without disassembly or removal of the entire systemConvenient access to internal componentsFewest number of o-rings Ease the burden on instrument and maintenance techniciansLower cost of spare parts


Wrap-Up

Please visit us in Booth 315/317Automated System Demonstration

pH and conductivity sensor array

Laboratory GC carrier gas metering system

New surface-mount components

Regulator

Solenoid Valve

pH and conductivity sensors

Discuss the topics presented

© swagelok company, 2004 cfd-based liquid flow calculations for modular sample systems john j....

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