High-coherent coolant jets for focused fluid delivery in grinding

1. High-coherence jets for
focused fluid delivery in grinding
Maxwell Lightstone, Philip Koshy, Stephen Tullis
CIRP Annals–Manufacturing Technology 70 (2021) 293 – 296.

2. rotating air layer
Ebbrell et al. (2000)
wheel
coolant jet
Rotating air layer presents a
barrier that deflects the coolant jet
1/16

3. Baines-Jones (2000)
shoe nozzle
Morgan et al. (2008)
mechanical disruption
Rezaei et al. (1992)
through-wheel delivery
2/16

4. Geilert et al (2017)
(b)
nozzle
core
jet boundary
air
Interaction of the jet with the
surrounding leads to air
entrainment, jet spread and
a reduction in liquid volume
fraction and jet momentum
This compromises coolant
ingress into the grinding
zone, which highlights the
importance of jet coherence
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5. Cool-Grind Technologies
Dr. Webster
Rouse nozzle
4/16

6. Laminar fountain @ the Detroit Metro Airport
Courtesy: WET Design
5/16

7. Gajbhiye et al (2020)
nozzle absorbs impact and
disperses flow
flow inlet
suppresses instabilities
from the tube bundle
tube bundle reduces the Reynolds number
and damps transverse velocity components
Flow laminarizing device developed in the present work
screens
coarse conditioning
of incoming flow
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8. 10 mm
@ nozzle exit
15 cm
45 cm
60 cm
Comparison of jet structure at a jet velocity of 20 m/s
Rouse nozzle
present work
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9. 10 m/s 20 m/s 50 m/s
35 m/s
10 mm
Comparison of jet structure at a standoff distance of 30 cm
Rouse nozzle
present work
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10. Abrupt transition in flow pattern
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11. coherent jet
air
5 mm
Hydraulic flip
nozzle
flow
cavitation cloud
edge
nozzle
flow
air
air
turbulent jet
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12. (c) (d)
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13. 45
jet
speed
(m/s)
10 15 20 25 30 35 40 45
0
1
2
3
4
5
6
7
10 15 20 25 30 35 40 45
0
1
2
3
4
5
6
7
wheel speed (m/s)
model
φ3.2 mm
model
φ4.0 mm
10 15 20 25 30 35 40
0
1
2
3
4
5
wheel speed (m/s)
flow
rate
(L/min.)
model
Rouse
present work
Model considers
momentum flux
per unit width of
the coolant jet
against that of
the air layer
Assessment of coolant jet breaching the radial air barrier
12/16

14. -6 -4 -2 0 2 4 6
0.0
0.3
0.6
0.9
1.2
1.5
1.8
force
(N)
distance normalized to nozzle radius
-6 -4 -2 0 2 4 6
30 cm
-6 -4 -2 0 2 4 6
60 cm
7 cm
Jet force on a target of width equal to the nozzle diameter
13/16
v
jet
target
Rouse
present work

15. Comparison of hydrodynamic forces
Disproportionate
increase in force at a
flow rate of 15 L/min
that corresponded to
the jet speed
approaching the
wheel speed
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15 L/min.
7.5 L/min. 15 L/min.
7.5 L/min.
Rouse p/w Rouse p/w Rouse p/w Rouse p/w
30 cm 45 cm
0.0
0.3
0.6
0.9
1.2
1.5
1.8
force
(N)
jet
F
vs 30 m/s, radial gap 25 µm
nozzle
flow rate
standoff distance

16. Grinding burn experiments
A60K8V wheel, vs 30 m/s, vft 20 mm/s
4 mm wide AISI 1020 workpiece
Nozzle performance was
largely comparable for a
standoff distance of up to
30 cm, but the flow laminarizer
outperformed the Rouse
nozzle by a factor of up to 6
on increasing it to 45 cm
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17. Belmont
Conclusions
Flow laminarization using a tube bundle in conjunction
with hydraulic flip enables coolant jets with extreme
coherence using simple cylindrical nozzles
Such jets are particularly suited for applications that
necessitate targeted fluid delivery and/or standoff
distances in excess of 30 cm
Further work will optimize the device for size and
pressure drop in consideration of the quality of the
inbound flow
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18. Belmont
Thank you
for your kind attention!
Natural Sciences & Engineering Research
Council of Canada
Canadian Network for
Research & Innovation in
Machining Technology
Dr. John Webster
Cool-Grind Technologies