© 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
© Swagelok Company, 2004
Agenda
Review of Previous Work
Flow Testing Description
Flow Testing Results
Is a larger standard required?
Important Considerations
Conclusions
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
Nine-Position System
© Swagelok Company, 2004
Test Set-up
Pressure regulator
Nitrogen Supply
Head Tank
Calibration fluid Diverter (timing)
Graduated cylinder
FLOW Control valve
Meter Assembly
Sump
DpT P
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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
© Swagelok Company, 2004
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