Design Optimization for Water

7/24/2019 Design Optimization for Water

1/19

Design Optimization for Water/ Wastewater Treatment and

Conveyance Systems usingCFD Modeling

Ferdous Mahmood, P.E. (VA)

Malcolm Pirnie / ARCADIS-US

Dallas, Texas


2/19

Computational Fluid Dynamics

Modeling 3-D visualization of liquids and gases in

motion

Calculates details of flow regime (such asvelocity, pressures, flow streamlines, forces,turbulence)

Cost effective evaluation of design andoperation Reduces extensive experimentation and

operational changes Optimizes design and shortens design cycle

Validates impact of proposed design


3/19

Tank Operational (Flow) Analysis

Lower Inflow Rate

Dark blue color implies

near zero velocity

Higher Inflow Rate

Lower flow produced poor mixing near the top of tank

Higher flow achieves better mixing throughout the tank


4/19

Seasonal (Temperature) Analysis

78.0

79.0

80.0

81.0

82.0

83.0

84.0

85.0

86.0

87.0

88.0

Temperature(deg.

F.)

0

1020

30

40

50

60

7080

90

100

110

120

130

140

150

WaterDepth(ft)

-20

0

20

40

60

80

100

120

140

Y

-25025 Z-20 0 20

X

-20

0

20

40

60

80

100

120

140

Y

-25025 Z-20 0 20

X

Isothermal Condition

Conc

0.8

0.6

0.4

0.2

0.1

0.01

Inflow 1 0C Less than Tank Bulk Water

78.0

79.0

80.0

81.0

82.0

83.0

84.0

85.0

86.0

87.0

88.0

89.0

Temperature(deg.

F.)

0

10

2030

40

50

60

70

80

90

100

110

120

130

140

150

WaterDepth(ft)

5' below water surface 40' below water surface 75' below water surface

140' below w ater surface Tank Level (ft)

Mixed

tankStratified

tank


5/19

Design Analysis - Radial Inlet

300

300

300

300

6 dia perforations

Outer sleeve

36 dia inlet pipe

outlet pipe

Velocity Contours


6/19

WWTP Clarifier Analysis

Velocity

Contours

(m/s)

Velocity

Contours

(m/s)


7/19

WTP Rapid Mix System Analysis


8/19

WTP/ WWTP Filter Flow

Distribution Analysis

Dead zone

Lower flow at this filter inlet


9/19

Baffle Design and CT Analysis

for Rectangular Tanks

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.510.0MassFraction

ofTracer(C

out/

Cin)

Time (hours)

Tracer Curve from CFD

Velocity

Contours

Inlet

Outlet

Baffle Walls

Tracer

Contours


10/19

Clearwell Tracer Movement

1

2

3

4

Tracer

Concentration

(0-1 mg/L)


11/19

Baffle Design and CT Analysis

for Circular Tanks

0

0.5

1

1.5

2

2.5

0 5 10 15 20 25 30 35

Conc(ppm)

Time (hours)

Comparisons of Breakthrough Curves

Modeled

Modeled+Cb

Measured

0.02

0.018

0.016

0.014

0.012

0.01

0.008

0.006

0.004

0.002

0

Z

Y

X

X

Close

agreement

between model

results andfield data


12/19

Clearwell Baffles


13/19

Chemical Injection and Mixing

AnalysisChemical

Injection

Plates

added

72

Pipe

Poor mixing of chemical

Chemical only in 2nd pipe branch

Good mixing of chemical

Chemical in both branches


14/19

Reservoir Short-Circuiting and

Water Age Analysis

Water Residence Time

Velocity Vectors

Water Residence

Time Distribution


15/19

Pump Station Design Evaluation

VelocityContours

(ft/s)


16/19

Pipe Valve Analysis

Velocity

Contours

(m/s)

Velocity

Contours

(m/s)

Valve location


17/19

Large Pipe Connection

EvaluationVelocity

Contours

(ft/s)

Velocity

Contours

(ft/s)

Junction box

High velocity at pipe intersection corner mitigated by

junction box


18/19

Dam Spillway and Aqueduct

Inlet/Outlet AnalysisSpillway

Entrance

Aqueduct

See attached

movie for analysis


19/19

Questions?

Ferdous Mahmood

Phone: 972-375-7965

Email: [email protected]

Design Optimization for Water

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