EFFECTS OF BOOSTER FANS IN VENTILATION NETWORKS – COMPUTATIONAL AND EXPERIMENTAL APPROACHES

8/9/2019 EFFECTS OF BOOSTER FANS IN VENTILATION NETWORKS COMPUTATIONAL AND EXPERIMENTAL APPROACHES

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EFFECTS OF BOOSTER FANS IN VENTILATION

NETWORKS COMPUTATIONAL AND

EXPERIMENTAL APPROACHES

Arash Habibi

and

Stewart Gillies

US Mine Ventilation Symposium

Salt Lake City 2012


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Introduction

Booster Fans Usage in The World

Experimental Mine Study

Booster Fans Installation

Computational Fluid Dynamic Approach

Conclusion

Outline


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Introduction

Booster fan is a large underground fan which is

installed in series with main fan to boost the pressure.

In the United States coal mines are required to use

surface fans for ventilation and the use of boosterfans is prohibited with the exception of anthracite

mines.

In the United States, Title 30 Part 75 Subpart D of theCode of Federal Regulations (CFR) defines the

requirements for underground coal mine ventilation

(Federal Register 2010).


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Booster fans in the world

Booster fans are used in mines in all foreign major

coal mining countries requiring this form of

ventilating air motivation including the United

Kingdom,Australia,Poland, South AfricaandChina.

In the United Kingdom, Australia, South Africa andmany other countries a performance-based approach

to regulation that emphasizes risk assessment

management is practiced.

For booster fans to be permitted in the UnitedKingdom for instance an extensive ventilation survey

must be conducted to identify how the ventilation

system is affected by booster fans.


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Mine is in dolomite. Mine is accessed by two adits and has three

raises to the surface along with the primary ventilation shaft.

MS&T Experimental Mine Study


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Ventilation Infrastructure

Experimental mine elbowMain fan


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P-Q Survey and Model

(Ventsim Visual)

West Booster Fan

Main Fan

East Booster FanWheeler Portal

Kennedy Portal


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Ventilation Stations

#1

#2

#4

#4

#5

#6

#7

#8

#9

#10

i di d i i l d


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Comparison of predicted Ventsim Visual and

experiments results

Vent Station

Q (m3/s)% Difference MQ vs

VQMeasured Quantity at

Mine

Predicted Ventsim Visual

Results

1 19.0 17.8 6.9

2 18.2 17.8 2.1

3 0.3 0.3 0.0

4 18.3 17.3 5.7

5 16.7 17.4 4.3

6 16.1 15.8 2.0

7 12.2 12.9 4.0

8 12.2 12.9 0.0

9 15.4 15.8 2.5

10 11.9 10.5 13

Average % Difference between measured and Ventsim quantities 4.1


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Booster fan characteristics curve:


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#P Area RL Adj Ps P Ps adj V w R K Q (m3/s) %

m m2 Pa kPa kPa Pa Pa m/s Kg/m

3 Ns2/m8 Ns2/m4 Experiment Ventsim

1 9.7 5.8 5.86 98.52 0.01 10 15.86 3.5 1.194 0.03848 0.0662 20.2 18.8 7.4

2 9.3 5.3 4.71 98.51 0.02 20 24.71 3.8 1.200 0.23521 0.6212 20.3 18.7 8.6

3 15.5 12.8 -7.09 98.49 0 0 7.09 0.02 1.205 0.07606 1.3190 0.2 0.2 0.0

4 11.9 8.7 -14.17 98.49 0.02 20 5.83 2.2 1.204 0.01534 0.0299 19.2 17.8 7.6

5 10.1 6.4 12.92 98.47 0.02 20 32.92 3.1 1.197 0.07675 0.0729 19.9 20.0 0.5

6 10.4 6.7 4.67 98.45 0 0 4.67 3.2 1.191 0.01233 0.0065 21.5 20.0 7.4

7 8.3 4.3 1.17 98.45 0.02 20 21.17 4 1.191 0.06954 0.0278 17.3 19.5 11.2

8 8.1 4.1 -14.08 98.43 -0.01 -10 24.08 4.3 1.196 0.06216 0.0256 17.5 19.5 10.5

9 10.3 6.4 -41.26 98.44 0 0 41.26 3.4 1.202 0.13270 0.0549 21.8 20.0 9.2

10 8.0 4.0 98.44 0 3.4 1.203 0.00000 13.5 11.9 13.0

Average % Difference between measured and Ventsim quantities 7.5

Scenario 3, Experimental and Ventsim Visual Results


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Bulkheads Construction

Blasting during 2011 Summer Explosives camp


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19/34Wedge Head Anchor Bolt

Cementitious Mixture

Expanded Foam Speray


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CFD Approach

As a mine gets older, leakage will increase asventilation pressure increases and ventilation structures

deteriorate.

Every stopping leaks after a while.

Recirculationis the main concern of using Booster

fan.

The CFD model of experimental mine has been built

based on the simplified Ventsim Ventilation model.


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Experimental Mine CFD Model

Booster Fan


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CFD Model Outline

G id i d d t t d h b d t d i GAMBIT


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Grid independent studyhas been conducted using GAMBIT

(650,000 to 1,200,000 tetrahedral cells).


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Simulation Results (No Booster Fan)

The CFD model has been calibrated with experimentalmeasurements.

Model

Air Quantity at Stations (m3/s)

1 2 3 StoppingLeakage

KennedyPortal

RaiseLeakage

Main outlet

Experiment 20.8 20.8 20.8 0.2 0.3 0.3 19.7

CFD 20.8 20.7 20.4 0.12 0.2 0.2 20.5

Difference% 0 0.5 2 66.7 50 50 3.9

No Fan Velocity
http://localhost/var/www/apps/conversion/tmp/scratch_7/Symposiom2012/ExpMine/Videos/nofanvelocity1.avihttp://localhost/var/www/apps/conversion/tmp/scratch_7/Symposiom2012/ExpMine/Videos/nofanvelocity1.avi


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A booster fan, when properly sized and sited, can be

used to assist surface fans to overcome highresistances and to ventilate isolated working

districts.

Uncontrolled recirculationis the main hazard

associated with the utilization of a booster fan.

Monitoring is a basic component of a booster fansystem. Reliable Monitoring System!!

Conclusions


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Conclusions (cont.) Legislative restrictions such as restricting use of

booster fans could force the closure of sub economic

operations.

Booster fans could be one of the solutions for

improving the ventilation network. However it is not

the only one. All the other alternatives should be

taken into account.

Three-dimensional CFD technique demonstrates the

airflow direction, pressure drop and the amount of

leakage across the stoppings and bulkheads.


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Acknowledgments

Acknowledgement and thanks extended to:

Dr. Gillies, Dr. Tien, Dr. Homan.

Dr. Thiruvengadam (for CFD analysis).

Experimental Mine and Rock Mechanics and Explosives

Research Center personnel (for fan installation).

NIOSH (for funding the project).

Spendrup (fans donation and advice).


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-75.91

-75.55

-76.58

-78.39

-79.51

-80.25

-80.69

-81.08

-81.58

-84.77

-84.76

-84.69

-85.18

110.77

111.62

114.96

123.23

124.43

124.62

-100

-50

0

50

100

150

0 10 20 30 40 50 60 70 80TotalPressure

(Pa)

Plane Distance (m)

Pressure Gradient

#RL X-area P Area L

RL

AdjPs P

Ps

adjTemp V w R K

m H W m m2 m Pa kPa kPa Pa Pa Wb db m/s Kg/m

3 Ns2/m8 Ns2/m4

1 301.5 2.1 2.8 9.7 5.8 10.5 5.86 98.64 0.01 10 15.86 10.0 15.0 3.3 1.1950.04567 0.0786

2 302.0 2.1 2.5 9.3 5.3 23 4.71 98.63 0 5 9.71 9.4 14.2 3.4 1.202 0.11461 0.3027

3 302.4 2.4 5.3 15.5 12.8 5.27 -7.10 98.63 0 5 2.10 10.8 11.9 0.02 1.2060.02456 0.4259

4 301.8 2.6 3.4 11.9 8.7 20.1 -14.19 98.62 0.03 30 15.81 10.3 11.9 2.1 1.2050.05196 0.1014

5 300.6 2.4 2.6 10.1 6.4 29 12.94 98.59 0.01 10 22.94 10.0 12.2 2.6 1.1990.08521 0.0810

6 301.7 2.4 2.8 10.4 6.7 34 4.68 98.58 0 5 9.68 10.6 15.0 2.4 1.1930.04415 0.0234

7 302.1 2.1 2.1 8.3 4.3 22.5 1.17 98.58 0.01 5 6.17 10.8 15.0 3.1 1.1930.03745 0.0150

8 302.2 2.2 1.8 8.1 4.1 38 -14.09 98.57 0.11 110 95.91 11.1 15.0 3 1.1970.50255 0.2069

9 301.0 2.1 3.0 10.3 6.4 37 -41.26 98.46 0.01 10 31.26 11.7 12.8 2.4 1.2020.16824 0.0696

10 297.5 2.1 1.9 8.0 4.0 98.45 0 11.7 12.2 3 1.2030.00000


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EFFECTS OF BOOSTER FANS IN VENTILATION NETWORKS – COMPUTATIONAL AND EXPERIMENTAL APPROACHES