AgendaAgenda

• Project BackgroundProject Background

• Initial Outlook

L fl t ti– Large flume testing

• Current Solution Path

– Smaller model testing

– Model substitutes

– Numeric and analytical approaches

• Critical Risks & Questions

BackgroundBackground

Green EnergyGreen Energy

Project FocusProject Focus

• What is the effect of upstream geometry on approach flow p g y ppconditions and unit performance at various installation angles?

• What is the submergence required to avoid drawing air or floating ice into the unit at various installation angles?

• What is the effect of flow over the turbine on unit performance?

• What is the effect of turbine installation angle on unit efficiency?

• What is the effect of tailwater depth on unit performance as a function of installation angle and the downstream hood design?

What is an optimal hood design fo a nea e tical installation?• What is an optimal hood design for a near-vertical installation?

• If two turbines are installed in series, what is the effect of turbine spacing on the approach flow conditions and performance?

• What is the survival rate of North American fish passing through the turbine?p g g

Existing ModelExisting Model

• Used in previous testsUsed in previous tests done at Laval

• 90 cm wide90 c de

• 90 cm tall (plus gate height)g )

• Approx. 500 L/s flow required

• Don’t currently have possession

Large FlumeLarge Flume

• Owned by the CivilOwned by the Civil Department

• 60 cm tall60 c a

• 5 m long

• Less than 1 5 m wideLess than 1.5 m wide

• 42 L/s flow rate

Large Flume SystemLarge Flume System

Possible Changes to Existing FlFlume

Advantages and Disadvantages of h L Flthe Large Flume

Advantages DisadvantagesAdvantages

• Superior data

• No model construction

Disadvantages

• Wall height is insufficient

• Flow rate is insufficientNo model construction Flow rate is insufficient

• Available power may not be sufficient

• Effects of increased water load unknown

• All changes must be• All changes must be approved by Civil

Other Testing OptionsOther Testing Options

• Smaller model in smaller flumeSmaller model in smaller flume

• Replicating conditions without a model

N i d l i l h d• Numeric and analytical methods

Smaller FlumeSmaller Flume

• 30 cm wide channel30 cm wide channel

• 60 cm tall walls

S fl l fl b i• Same flow as large flume, but appropriate for a 30 cm model

• Results may be less meaningful

Targeted Nominal Design PointsTargeted Nominal Design Points

Reynolds Number Froude's Number

Smaller FlumeSmaller Flume

• With 60 cm walls, •With 60 cm walls, we assumed we can obtain around

•

•0.5m of head

• From targeted

•• In our case, =

1 6 so Froudeg

nominal design points

1.6, so Froude similitude is satisfied

Q = 44.5 L/s

N = 247.5 rpm

Webers NumberWebers Number

• Describes surface tension interactionsDescribes surface tension interactions between two fluids

• Not a significant factor in our open flow• Not a significant factor in our open flow experiment

N i d i h L l U i i• Not mentioned in the Laval University Reports

• Further investigation should be done

Testing on 30cm scale modelTesting on 30cm scale model

• Requires design (drawings) constructionRequires design (drawings), construction, and assembly

Estimated cost of $3700– Estimated cost of $3700

• Requires dynamometer to find efficiency

• Has the advantage of being able to directly measure power.

• IEC 60193 standards

Alternatives to Scale ModelsAlternatives to Scale Models

• Could simulate the turbine with a simpleCould simulate the turbine with a simple pressure drop

Ideal substitute would also induce a swirl into– Ideal substitute would also induce a swirl into the flow.

• Has the advantage of being much cheaper• Has the advantage of being much cheaper, but would require interpretation of results

Effi i t b bl• Efficiency may not be measureable

Other Test IdeasOther Test Ideas

• Dye visualizationDye visualization tests

• Pressure profile• Pressure profile measurements

Pit t t b– Pitot tube measurements

Computational Fluid DynamicsComputational Fluid DynamicsAdvantages:

• Available in all MEB Computers

• Proper CFD modeling can produce useful results

Disadvantages:

• Time consuming

A il bl CFD S ft

Obtainable Results:

• Flow and pressure profiles across the mesh VLH Turbine model for different

Available CFD Software

mesh VLH Turbine model for different approach geometries and turbine installation angles

Potential Flow AnalysisPotential Flow AnalysisAdvantages:

• Basic understanding of fluid motion

Disadvantages:

• Potential Flow represents ideal fluid behaviour, and thus does not represent entirely the flow in reality

Obtainable Results:

• Streamlines and pressure profiles for fluid flow upstream and downstream of theflow upstream and downstream of the turbine at different approach geometries and turbine installation angles

QuestionsQuestions

• Scaling viability of a small model?Scaling viability of a small model?

– Cavitation? Other dimensionless numbers?

Faithful representations without a model• Faithful representations without a model:

– What conditions must be accurately replicated?

– How useful would the results be?

• Any concerns you see?