The Challenge of Designing for Low head...Presentation by Jacob Arnold (MSc) Director Research & Development Pentair Fairbanks Nijhuis The Challenge of Designing for Low head PENTAIR

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Presentation by Jacob Arnold (MSc)

Director Research & Development Pentair Fairbanks Nijhuis

The Challenge of Designing for Low head

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AS ONE COMPANY, WE HAVE THE GLOBAL RESOURCES

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30,000 EMPLOYEES

6 CONTINENTS

500+ PRODUCT

LINES

100+ MANUFACTURING

FACILITIES

$8 Billion ANNUAL REVENUE

90+ SERVICE CENTERS

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An opportunity

A challenge

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ULTRA-LOW HEAD FISH FRIENDLY TURBINES

• High energy production (maximum yield)

• High efficiency at head ranging from 0.2 – 3 [m] (optimal control)

• Minimal impact on aquatic life (fish, eel)

• Minimal impact of aquatic environment (corrosion, fouling)

• Low manufacturing cost (simple modular design)

• Low operational cost (ease of maintenance)

• Bi-directional operation for tidal applications (symmetry)

• Pumping function might be essential (level control, storage)

General Turbine Requirements

Most requirements are challenges

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ULTRA-LOW HEAD FISH FRIENDLY TURBINES

Selection of turbines for optimum yield

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0,2

0,4

0,6

0,8

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1,2

0 0,2 0,4 0,6 0,8 1 1,2

Pow

er fa

ctor

(p),

Fl

ow re

duct

ion

fact

or (q

)

Velocity ratio (a), Pressure ratio (f)

Current versus Head Turbines

p - current q - current p - head q - head

Challenge: Optimize civil construction for optimal yield

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Development of a fish collision model

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QLnpo

b

ULTRA-LOW HEAD FISH FRIENDLY TURBINES

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Example prediction of fish mortality

ULTRA-LOW HEAD FISH FRIENDLY TURBINES

Challenge: Optimize design for fish friendliness – minimum impact on yield

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ULTRA-LOW HEAD FISH FRIENDLY TURBINES

Extensive CFD analysis to optimize efficiency Run-off-river turbines

Tidal turbines

Challenge: Optimize efficiency retaining fish friendly design

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FISH FRIENDLY RUN-OFF-RIVER TURBINES

First prototype developed by Pentair - Nijhuis

Fish-friendly turbine – φ800 mm

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Measured performance scaled (1:5) to prototype

FISH FRIENDLY RUN-OFF-RIVER TURBINES

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Reduced number of runner blades

Spherical wear ring (no gap) Speed controlled PM-

generator

Reduced number of guide vanes

Design features of the one-directional turbine

Simplified control

Simplified transmission

Challenge: Create a robust design – reliable, minimizing maintenance

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Mortality rates eels – Tested by IMARES Group Control Turbine,

guide vane 30° Turbine, guide vane open

Trial order 3 5 2 4 1 6

N eels recovered after trial 73 63 79 70 80 93

Fraction wild caught eel 0.64 0.73 0.71 0.69 0.70 0.71

Mean length [cm] 42.0 40.7 40.6 40.3 41.3 42.8

Length range (cm) 32-75 31-64 31-76 28-60 31-75 31-84

Direct mortality % 0 % 0 % 0 % 0 % 0 % 0 %

Normal swimming % * 100 % 100 % 100 % 100 % 100 % 100 %

Mortality after 96 h % 1.5 % 0 % 1.2 %

FISH FRIENDLY RUN-OFF-RIVER TURBINES

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Retrofits conventional turbines

FISH FRIENDLY RUN-OFF-RIVER TURBINES

Challenge: Optimize design subject to existing constraints

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FISH FRIENDLY TIDAL TURBINES

Bi-directional turbine design

Challenge: Create an efficient bi-directional design

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FISH FRIENDLY TIDAL TURBINES

Scale model (1:10) ultra-low head tidal turbine

Design Properties: Diameter = 500 [mm] Head = 1 ± 0.75 [m] Flow = 1.40 ± 0.8 [m³/s] Speed = 300 ± 100 [rpm] No. blades = 2 (fixed) Rotor pitch ± 180 [degrees]

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FISH FRIENDLY TIDAL TURBINES

Performance prototype scaled from measurements

constQHQH ssss =�� 22 /,constQHNQNH tttt =��� 22 /,,

System characteristic: Turbine characteristic:

Q = Flow rate

H = Head difference

N = Rotation speed

System line Hs = f(Q)

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FISH FRIENDLY TIDAL TURBINES

Pumping function - Variation speed of rotation

Pump

Turbine

Pump

Turbine

Power

Head

Challenge: Optimize design for pump/turbine

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FISH FRIENDLY TIDAL TURBINES

Mortality rates fish and eels – Tested by ATKB

Results SCALE MODEL (0.5m): Fish: >96 [%] undamaged Eel: 100 [%] undamaged

Predicted LARGE SCALE (8m)* : Fish: >99.8 [%] undamaged Eel: >99.9 [%] undamaged

* Pro-Tide Report – Dr. Ir. B. P. M. van Esch (TUe)

FLOW TECHNOLOGIES – FAIRBANKS NIJHUIS 19

• High energy production (maximum yield)

• High efficiency at heads ranging from 0.2 – 3 [m] (optimal control)

• Minimal impact on aquatic life (fish, eel)

• Simple robust designs (minimal components)

• Pumping function demonstrated

Conclusion: Ultra low head fish friendly (bi-directional) turbines are developed by

Pentair Fairbanks Nijhuis featuring:

Next step is to demonstrate operational aspects (fouling, corrosion, wave

action, etc.) on a larger scale – e.g. TTC Lake Grevelingen, Holland

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FLOW TECHNOLOGIES – FAIRBANKS NIJHUIS

Q & A

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