The Challenge of Designing for Low head

Transcription

1 The Challenge of Designing for Low head Presentation by Jacob Arnold (MSc) Director Research & Development Pentair Fairbanks Nijhuis PENTAIR 1

2 AS ONE COMPANY, WE HAVE THE GLOBAL RESOURCES 30,000 EMPLOYEES 6 CONTINENTS $8 Billion ANNUAL REVENUE 100+ MANUFACTURING FACILITIES 500+ PRODUCT LINES 90+ SERVICE CENTERS PENTAIR 2 2

3 An opportunity A challenge 3

4 ULTRA-LOW HEAD FISH FRIENDLY TURBINES General Turbine Requirements High energy production (maximum yield) High efficiency at head ranging from [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) Most requirements are challenges PENTAIR 4

5 ULTRA-LOW HEAD FISH FRIENDLY TURBINES Selection of turbines for optimum yield Current versus Head Turbines 1,2 Power factor (p), Flow reduction factor (q) 1 0,8 0,6 0,4 0, ,2 0,4 0,6 0,8 1 1,2 Velocity ratio (a), Pressure ratio (f) p - current p - head q - current q - head Challenge: Optimize civil construction for optimal yield PENTAIR 5

6 ULTRA-LOW HEAD FISH FRIENDLY TURBINES Development of a fish collision model p 4 n L [ ] ( sin( )) 1 e [ ] 3 2 b Q o PENTAIR 6

7 ULTRA-LOW HEAD FISH FRIENDLY TURBINES Example prediction of fish mortality Challenge: Optimize design for fish friendliness minimum impact on yield PENTAIR 7

8 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 PENTAIR 8

9 FISH FRIENDLY RUN-OFF-RIVER TURBINES First prototype developed by Pentair - Nijhuis Fish-friendly turbine φ800 mm PENTAIR 9

10 FISH FRIENDLY RUN-OFF-RIVER TURBINES Measured performance scaled (1:5) to prototype PENTAIR 10

11 Design features of the one-directional turbine Reduced number of guide vanes Simplified transmission Simplified control Reduced number of runner blades Speed controlled PMgenerator Spherical wear ring (no gap) Challenge: Create a robust design reliable, minimizing maintenance PENTAIR 11

12 FISH FRIENDLY RUN-OFF-RIVER TURBINES Mortality rates eels Tested by IMARES Group Control Turbine, guide vane 30 Turbine, guide vane open Trial order N eels recovered after trial Fraction wild caught eel Mean length [cm] Length range (cm) 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 % PENTAIR 12

13 FISH FRIENDLY RUN-OFF-RIVER TURBINES Retrofits conventional turbines Challenge: Optimize design subject to existing constraints PENTAIR 13

14 FISH FRIENDLY TIDAL TURBINES Bi-directional turbine design Challenge: Create an efficient bi-directional design PENTAIR 14

15 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] PENTAIR 15

16 FISH FRIENDLY TIDAL TURBINES Performance prototype scaled from measurements Q = Flow rate H = Head difference N = Rotation speed System line H s = f(q) System characteristic: Turbine characteristic: 2 2 H s Qs, H s / Qs = 2 2 H N, Q N, H / Q t t t t = const const PENTAIR 16

17 FISH FRIENDLY TIDAL TURBINES Pumping function - Variation speed of rotation Pump Power Turbine Pump Head Turbine Challenge: Optimize design for pump/turbine PENTAIR 17

18 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) PENTAIR 18

19 Conclusion: Ultra low head fish friendly (bi-directional) turbines are developed by Pentair Fairbanks Nijhuis featuring: High energy production (maximum yield) High efficiency at heads ranging from [m] (optimal control) Minimal impact on aquatic life (fish, eel) Simple robust designs (minimal components) Pumping function demonstrated Next step is to demonstrate operational aspects (fouling, corrosion, wave action, etc.) on a larger scale e.g. TTC Lake Grevelingen, Holland FLOW TECHNOLOGIES FAIRBANKS NIJHUIS 19

20 Q & A FLOW TECHNOLOGIES FAIRBANKS NIJHUIS 20