12th U'S' North American Mine Ventilation Symposium Study on the effects of scrubber operation on th

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12th U.S./ North American Mine Ventilation
SymposiumStudy on the effects of scrubber
operation on the face ventilation

• A.M. Wala, University of Kentucky
• S. Vytla, G.Huang, Wright State University
• C.D. Taylor, NIOSH

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Outline

• Objective
• Background
• Experimental studies
• CFD simulation studies
• Conclusions

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Objective

• Validate the Fluent as a CFD simulation tool for
  evaluation and design of modern underground coal
  mine face ventilation systems
• Better understand how the use of a mining
  machine-mounted dust scrubbers affects the
  airflow and methane behavior at the face area

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Background

• For the past seven years, the Department of
  Mining Engineering at the University of Kentucky
  has conducted a validation study of the CFD
  codes, by comparing its results against an
  experimental data
• During the first four years, the experimental
  data was generated using scaled physical model

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View of the scaled physical model
115 scaled model of the face ventilation system
with PIV flow monitoring system was designed and
built
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Results of the experimental studies - flow
patterns
(1 - 2) 30 ft deep box cut w/ w/o slab,
35 ft setback
(3 - 4) 60 ft deep box cut w/ w/o slab, 65
ft setback
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3
2
4
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Full-scale physical modelThe authors
validated the scaled model results by using a
full-scale testing gallery at the NIOSH
Pittsburgh Research Center
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Computer simulation study using CFD To determine
the feasibility of using CFD as a tool to
accurately predict the flow patterns within the
face area, two numerical codes, Fluent and CFX,
were tested
PIV

• Mining Scenarios
• 30 ft Box cut
• 30 ft Slab cut
• 60 ft Box cut
• 60 ft Slab cut

End of Curtain, 35ft setback
Fluent - Coarse
Fluent - Fine
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Computer simulation study using CFD
PIV

• Mining Scenarios
• 30 ft Box cut
• 30 ft Slab cut
• 60 ft Box cut
• 60 ft Slab cut

End of Curtain, 35ft setback
CFD Fluent Coarse Fine
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Scaled models with scrubber
The scrubbers performance was tested using the
scaled physical model and simultaneously examined
using developing CFD models of these scenarios

• Simulated scrubber in equipment-free entry for 60
  ft deep cut (30 ft box cut with 65 ft setback
  curtain).
• Simulated machine-mounted scrubber for 30 ft
  deep box cut with 35 ft setback curtain.

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Comparison between PIV and CFD data for 30ft deep
cut for the Qs/Qin ratio in the range of 20
Q s / Q in 18
Q s / Q in 20
PIV Data
CFD Data
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PIV results, 30ft deep cut, miner with the
machine-mounted scrubber, for two different
Qs/Qin ratios
Q s / Q in 30
Q s / Q in 53
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CFD results for 30ft deep cut with
machine-mounted scrubber, for different Qs/Qin
ratios
Q s / Q in 40
Q s / Q in 70
Q s / Q in 100
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Background (cont.)

• In the last three years, since the methane was
• introduced the mining-related benchmark
  experimental studies were performed in the
  NIOSHs Pittsburgh Research Laboratory in
  coordination with University of Kentucky
• First part of these studies were dedicated to the
  airflow and methane behavior in an empty face
  area
• Results of this study was published in Mining
• Engineering, October 2007

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Airflow and methane distribution in an empty
face area(box cut with flow behind the curtain
being 6,000cfm)

SA Turbulence model
SST Turbulence model
Experimental data
Simulation results
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Experimental results
Methane measured at three planes, 36 points at
each plane, for a total number of methane
measuring points of 108
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Experimental and simulation results
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Experimental and numerical study on the effect
of machinemounted dust scrubber on the
performance of face ventilation system
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Experimental Studies at NIOSH Laboratory
Main exhaust fan
Methane introducing manifold setup 4 pipes 12 ft
length, 3 away from face
Face area
Continuous miner
Blowing curtain
Regulator doors
Ventilation testing gallery
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Methane measurement

• Methane concentration measurements were taken at
  the 28 sampling locations at two levels above the
  continuous miner upper level being 0.4m (1.3ft)
  from the roof and lower level being 0.74m (2.4ft)
  from the roof for a total number of methane
  measuring points of 56.

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Testing scenarios (Qs/Qin ratio)

• 1. Scrubber off, intake flow 4,000 cfm,
• Qs/Qin 0.0
• 2. Scrubber flow 4,000 cfm,
• intake flow 4,000 cfm,
• Qs/Qin 1.0
• 3. Scrubber off, intake flow 6,000 cfm,
• Qs/Qin 0.0
• 4. Scrubber flow 4,000 cfm,
• intake flow 6,000 cfm,
• Qs/Qin 0.66

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Measured methane concentration contour maps

• Qs 0

Scenario 1 Qs 0.0 cfm QIN 4,000cfm
Scenario 2 Qs 4,000cfm QIN 4,000cfm
Scenario 3 Qs 0.0cfm QIN 6,000cfm
Scenario 4 Qs 4,000cfm QIN 6,000cfm
Methane inflow 13.4 cfm
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Geometry of the simulated face area with
continuous miner
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Boundary conditions
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Computational mesh
top view of the mesh
side view of the mesh
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Simulated methane concentration contour maps
Scenario 1 Qs 0.0 cfm, QIN 4,000cfm
Scenario 2 Qs 4,000cfm, QIN 4,000cfm
Scenario 4 Qs 4,000cfm, QIN 6,000cfm
Scenario 3 Qs 0.0cfm, QIN 6,000cfm
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Scenario 1 (Qs 0.0, Qin 4,000cfm)
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Scenario 2 (Qs 4,000cfm, Qin 4,000cfm)
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Scenario 3 (Qs 0.0, Qin 6,000cfm)
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Scenario 4 (Qs 4,000cfm, Qin 6,000cfm)
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Comparison of measured and simulated methane
concentration (Scenario 1)
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Comparison of measured and simulated methane
concentration (Scenario 2)
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Comparison of measured and simulated methane
concentration (Scenario 2)
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Comparison of measured and simulated methane
concentration (Scenario 4)
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Conclusions and future work

• Such studies had never before been tried to
  such an extent.
• By conducting these studies, a vast amount of
  knowledge is
• gained about the mine face ventilation
  process
• The flow patterns at the face area, especially
  for the box cut
• scenarios, were determined (better understood)
• The mechanics of the machine mounted scrubber
  effect on the
• airflow and methane distribution in the face
  area were seen
• Based on these studies, there is potential for
  using
• FLUENT CFD code to develop stand-alone face
  ventilation
• system design simulation packages
• Some differences between the experimental and
  simulated
• data were found during the last
  investigations. The reasons for
• these differences must be determined and
  proved by
• performing additional tests

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Acknowledgements

• This study was supported by the National
  Institute of Occupational Safety and Health
  (NIOSH) under Grant R01/CCR415822,
• years 2000 - 2004

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QUESTIONS ????