Tennessee Valley Authority (TVA) Projects Using PHOENICS - Cham

Tennessee Valley Authority (TVA) ProjectsUsing PHOENICS

Example 1:Colbert Fossil Plant Skimmer Wall

Barge Collecting Debris at COF, 2001

Debris Impact on COFTVA lost 16,030 MWhfrom 1994-2000 due todebris.After 2000, trashboom deteriorated atCOF.TVA lost 80,000 MWhdue to debris buildupat COF in 2001.(June 1999)

COF Skimmer Wall Objectives• Reduce intake temperatures• Minimize debris at pumping station• Minimize Fish impingement• Improve plant efficiency

Sediment Deposit Blocking Cold River WaterColbert Intake Channel Bottom Surveyed September, 1996intake units

New skimmer wall brings cool water to plant, keepswarm water and Debris in the reservoir.444440436432Intake StructureElevation (ft)428424420416412408404400396392420 ftSummer Pool Elevation 414 ftWinter Pool Elevation 408 ftCOF Intake Bottom Channel400 ftSkimmer WallTennessee River3880 20 40 60 80 100 120 140 160 180 200 220 240 260 280Distance from Intake Structure (ft)

Schematic Potential Layout of COF Skimmer Wall, Option 2 (Preferred Design)Cost = $1,313,000Pickwick Landing430428426424422420418416414412410408406404402400398396394392390Max Pool (1958-2001) = 418.5Min Pool (1958-2001) = 407.8Cell 27Cell 25Pier 3Pier 2 Pier 10 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360D is ta n c e fro m L e ft to R ig h t C e ll (ft)25.287.0 88.488.487.018.4 18.4 18.4Wall 3Wall 2Wall 4Pier 3 Pier 2 28.2Pier 1Wall 125.2Existing Cell 27181L Wall= 67.5Existing Cell 25*All numbers are in feetIntake Structure195

Intake Channel Numerical Representation in CFDTennessee RiverFlowSkimmer WallExisting Cell 25IntakeStructurePiersExisting Cell 27Bottom Channel

Computed Velocity Profile Contours at Several Locations of the Skimmer Wall(m/s)Existing Cell 25IntakeStructureFlowPiersTennessee RiverMax. Velocity Under Skimmer WallMin. Velocity Under Skimmer WallExisting Cell 27

0.2 0 0.2 0.4 MilesTennessee RiverNumerical Modeling BoxRiver FlowCoal BargesCOFIntakeChannelAerial View of COF and Tennessee River

Computed Flow Field at COF Intake Channel Vicinity with Hydro Release,(Existing Conditions)(m/s)Tennessee RiverRiver FlowBargesExisting CellsIntake ChannelExisting Cells

Computed Flow Field at COF Intake Channel Vicinity with No Hydro Release,Existing ConditionsTennessee RiverVelocity (m/s)No Hydro ReleaseIntake Channel

COF Skimmer Wall During and After ConstructionDuring Skimmer Wall Construction04-2002Potential Savingabout $20 Millionsfor the next 25 yearsResultsWall Construction Finished07-2002Cost = $1.4 MillionsNo debris cleaning since theconstruction of the wall.TVA lost 0 MWh due to debrisbuildup at COF since construction.An average improvement ofabout 0.25 °F in intake watertemperature.Lower Base line 316(b) ruling

Example 2:Multi-Port Diffuser Kingston Fossil Plant

Survey at KIF intake Channel

(m/s)Velocity Vector taken at Several Intake Channel Sections

Plan View of the Recommended Diffusers Design

Diffusers Angled at 45 degree, Instantaneous MixingContours at Elev. 732 feet, NH3Concentration = 0.23 Mg/L, 100 feetdownstream the Bridge.

Computed NH 3 Concentrations Downstream of KIFDiffusersElevation (feet)739.9736.4733.2730.8730.2729.2726.9724.5722.2719.90 3 6 9 12 15 22 27 33 38 53 73 94 119 150Distance from Diffusers (feet)NH3 (mg/L)2.75-3.002.50-2.752.25-2.502.00-2.251.75-2.001.50-1.751.25-1.501.00-1.250.75-1.000.50-0.750.25-0.500.00-0.25

Construction Started in October 2003

Before (11-2002)During (10-2003)“At an estimated price of $500,000,Deskins (KIF plant Manager) says themain advantage of this proposal,besides being environmentally friendly,is the cost savings — $7.5 million atmost or at least $3.5 million”. (InsideTVA, August 2003)After (01-2004)

Example 3:Surface Water Pumps at Tims Ford Reservoir

Example 3:Surface Water Pumps at Tims Ford ReservoirObjective: Evaluate surface water pumps performance under severalconfiguration layouts, pump sizes, and initial propeller velocities.Goal: Determine an optimum design that maximizes the improvement of watertemperature and dissolved oxygen (DO) content in hydropower plant releaseswithout disturbing reservoir bottom sediment.Tools: A 3-dimensional Computational Fluid Dynamics (CFD) model, PHOENICS.Alternatives: Several modeling analysis for different locations, operating speed,with three and six pump layouts.

surface-water pumps are being Used at Douglasand Cherokee ReservoirsImpeller forces higher DO andwarmer water at the surface downto the turbine intake

900880Elevation (ft.)860840820800MeasuredRegressionForebay Measured Temperature780760y = 6E-05x 5 - 0.0189x 4 + 2.4366x 3 - 155.56x 2 + 4923.8x - 61080R 2 = 0.989174044 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86Temperature (°F)900880860Elevation (ft.)840820800MeasuredRegressionForebay DO Profiles (6-26-03)780760y = -0.0449x 4 + 0.9374x 3 - 5.8603x 2 + 11.112x + 871.24R 2 = 0.96977407200 1 2 3 4 5 6 7 8 9 10 11 12DO (mg/L)

Velocity Vectors (Base Case)Withdrawal Zone

Using Measured Temperature Profile (06-26-2003)Numerical DomainComputed water temp. release = 48.7°FMeasured (Grab sample) = 48.7°FClose-UpCold Water Out = 48.7°F

Velocity Vectors with Three Pumps

Warm Water is “pushed Toward the IntakeT out = 62.6 o FComputed Temperature atIntake Vertical Centerline(Six Pumps)Water with High DO Level is“Pushed” Toward the IntakeComputed DO at IntakeVertical Centerline(Six Pumps)DO out = 2.0 mg/L

RecommendationThe option recommended is six 8-ft pump layout. Under the June 26,2003, forebay profile, the water temperature release was improved by10.3°F and the DO by 2.0 mg/L.