The Challenge of Designing for Low head...Presentation by Jacob Arnold (MSc) Director Research &...
Transcript of The Challenge of Designing for Low head...Presentation by Jacob Arnold (MSc) Director Research &...
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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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Pow
er fa
ctor
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Fl
ow re
duct
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fact
or (q
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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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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)
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• 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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Q & A
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