Hydrodynamics Studies on Oscillatory Flow Technology in Minichannels

1. Preliminary Investigation on Hydrodynamics
Characteristics of Oscillatory Flow Technology
in Minichannels
Kirubanandan. Shanmugam,
Graduate Research Student,
Minifluidics Research Laboratory,
Dept. of Process Eng.
Dalhousie University.
Dr. Adam. A. Donaldson,
Principal Investigator and Assistant Professor,
Minifluidics Research Laboratory,
Chemical Engineering,
Dept. of Process Eng.
Dalhousie University.

2. Oscillatory Flow in Process Equipment
• Radial mixing through vortex shedding propagation
A.P. Harvey, M.R. Mackley, T. Seliger. “Operation and optimization of an oscillatory
flow continuous reactor” Ind Eng Chem Res, 40 (23) (2001), pp. 5371–5377

3. Mini-fluidic Contactors for Enhancing Mixing
• Mixing/Heat transfer enhanced through static mixing
geometries

4. Objectives of Work
• Can we induce an oscillating field into a mini-fluidic
system?
• Challenges:
• Avoiding cavitation on suction-based systems
• Scale of geometries limit the use of moving baffles

5. Context of Work Compared to Passive Mixers
• Heat transfer analysis through scaling of conventional
correlations – representative of mixing
(Not to scale)
• Assumed properties of water

6. Nu vs. Energy Dissipation
Reo/Re ranging from:
0.2 at high Re
to 4 at low Re

 Dfx oo
o
)2(
Re 

7. Comparison to Other Geometries?
dh ~ 0.67 mm
dh ~ 1mm
Corning
“Heart”
reactor
Data from Plouffe P., Anthony R., Donaldson A., Roberge D.M.,
Kockmann N., Macchi A., ICNMM 2012

8. Preliminary Trial
• Development and characterization of a
“high-frequency” oscillating pressure field generator
(0 to 30 hz) with significant displacement capabilities
• experimental analysis of Oscillatory flow in existing
experimental set up.

9. Experimental System in Development
• Design of coupled high-speed switching
device for alternating the pressure field
• Resistance model & characterization of
flow (fluid displacement vs. time under
oscillatory conditions)

10. Results – 69 RPM, 1.17 Hz

11. Results – 175 RPM, 2.93 Hz

12. Results
• Generated Oscillatory flow at two different
frequencies (1.17 hz and 2.93 hz)
• Re0 = 8731, based on the L/d estimated for both flow
paths between sensors and pressure-based flow
assumptions.

13. Challenges
• Current valve design has packing issues with
continuous rotation
• Noisy signal for quantified analysis
• Flow path bypassing when valve rotating. Appears to
reduce when rotation initiated (based on pressure
field).

14. Conclusion
• Rotating valve assembly was able to generate an
oscillatory pressure field that could potentially apply
in the low energy dissipation region
• A number of challenges still exist in it’s use,
specifically in terms of inducing net flow, avoiding
leaks, and characterization at higher oscillation
frequencies with the signal noise.

15. Questions

16. Description of Conventional Correlations

17. References
1. P.Stonestreet and A.P.Harvey. “A mixing based design methodology for
continuous oscillatory flow reactors" Trans.I.Chem.Engg. 80, pp 31-44, 2002.
2. A.P. Harvey, M.R. Mackley, T. Seliger. “Process intensification of biodiesel
production using a continuous oscillatory flow reactor” Journal of Chemical
Technology and Biotechnology, 78 (2–3) (2003), pp. 338–341.
3. A.P. Harvey, M.R. Mackley, T. Seliger. “Operation and optimization of an
oscillatory flow continuous reactor” Ind Eng Chem Res, 40 (23) (2001), pp. 5371–
5377.
4. Norbert Kockmann and Dominique M.Roberge. “ Scale-up concept for modular
micro structured reactors based on mixing, heat transfer and reactor safety”
Chemical Engineering and Processing, 50, 1017-1026,2011.
5. M.R. Mackley and P.Stonestreet. “Heat Transfer and Associated Energy
Dissipation for Oscillatory flow in Baffled tubes” Chemical Engineering Science,
50,14,2211-2224,1995.