Hydropower, Hydroelectricity and Hydraulic turbine

Wei Zhao Senior Engineer, Energi Tekknik AS Email: [email protected] Tel:+47-40334263

Content • Hydropower • Hydroelectricity • Hydraulic Turbines • Small Hydro Power Plant in Norway

Hydropower

Hydropower Benefits  Renewable：Hydrologic Cycle never stop  Clean：Zero release  Reliable： It is a fast, flexible, stable power production of materials  Inexpensive：the cost per MWh is only 1/3 of fossil and nuclear fuel, less than 1/6 of gas  Multipurpose：Flood control，aquaculture industry， inland shipping，municipal water supply, irrigation agriculture and so on. 

Abundent: 1/5 of the power in the world

Hydropower Benefits

Hydropower

Hydroelectricity  Principle  Generating methods

 Advantages and disadvantages  World hydroelectricty capacity

Hydroelectricity  Principle

Generating methods  Dams (with reservoirs) • • •

Small dams with night&day regulation Large dams with seasonal storage Pumped-storage: reversible plants for energy storage and night&day regulation according to electricity demand.

 Run-of-the river (without reservoirs)  Tide: use the daily rise and fall of ocean water due to tides.

Advantages and disadvantages  1. 2. 3. 4. 5.

Advantages： Flexibility Low power costs Suitability for industrial applications Reduced CO2 emissions: clean Other uses of the reservoir: Irrigation, control floods

 1. 2. 3. 4. 5.

Disadvantages: Ecosystem damage and loss of land Siltation and flow shortage Methane emissions (from decomposition of organic materials in reservoirs) Relocation Failure risks: The Banqiao Dam failure （板桥大坝，河南）in 1975, 26000 people died.

World hydroelectric capacity In 2010, a total capacity of 723 GW in the world, 3190 TWh per year. In 2050, increase to 1700 GW, 5000-5500 TWh per year

 China: the largest hydroelectricity producer, 721 TWH in 2010, 17% of the domestic electricity use.  Norway: 99% of its electricity from hydroelectric, 122TWH in 2009, 30% of the hydroelectric in the west Europe.

Hydraulic turbines  Introduction  Classification of Turbines

 Choice of Turbines  Main Components of Turbines  Turbine design (according to my work)

Hydraulic turbines  Introduction Hydraulic turbines is a machine that directly convert the hydraulic power in a water fall to mechanical power on the machine shaft.

Working parameter     

Head：Hn, Hg Discharge：Q Power: P Rotational speed：n Efficiency：η

Hydraulic turbines  Introduction Gross head: Hgr=Zres-Ztw Net head: Hn=Hgr-HL

Available output: P=ρgQHn Efficiency: ηh=PT/ρgQHn

Hydraulic turbines  Classification of Turbines Francis turbine Reaction turbine (Full turbine) Both pressre and kinetic energy

Hydraulic turbines

Kaplan turbine

Bulb turbine

Mechanical energy

Only kinetic energy

Impluse turbine (Partial turbine)

Pelton turbine

Turgo turbine

Hydraulic turbines Pelton turbine  Invested by Lester Allan Pelton in 1870s  Head ranges higher than 750m  Widely used in Norway

Hydraulic turbines Francis turbine  Developed by James B. Francis in 1849  Head ranges:15-700m  H<300m, low head FR  H>300m, high head FR  η>95%  Widely used in China

Hydraulic turbines Three Gorges runner    

Head: 80.6m Speed: 75rpm Power: 710 MW 32 units

Hydraulic turbines Kaplan turbine  Invented by Austrian Professor Viktor Kaplan in 1913  Propeller blades  Head ranges 10-70m  Fixed runner blades  Adjustable runner blades

Hydraulic turbines Bulb turbine  Head ranges: low heads up to 30m  due to run-off-river type of the operation

Hydraulic turbines Pump-turbine  Pump: consume energy to perform mechanical work by moving the fluid.  Turbine: extracts energy from the fluid flow and converts it to a useful work

 7 pumped storage power plants in Norway

Hydraulic turbines  Choice of turbines

Reduced paramters are values relative to the highest velocity that can be obtained if all the nergy is vonverted to kinetic energy

Speed number: dimensionless and all geometrically similar turbines have the same speed number *

   *

*

Q

Hydraulic turbines  Choice of turbines Rule of Thumb 

Ω<0.2

Pelton turbines

 0.2< Ω<1.5

Francis turbines

 Ω>1.5

Kaplan turbines

Hydraulic turbines  Choice of turbines

High head, low flow

Intermediate head and flow

Low head, high flow

Main Components of Turbine     

Spiral casing Stay vanes Guide vanes Runner Draft tube

Main Components of Turbine  Spiral casing  The spiral casing will distribute the water equally around the stay vanes.  The flow has to be uniform into the stay vanes in order to achieve a uniform flow into the runner

Main Components of Turbine  Stay vanes  The main purpose of using stay vanes is to keep the spiral casing together.  Dimensions have to be given due to the stresses in the stay vanes  The vanes should be designed so that the flow is not disturbed by them

Main Components of Turbine  Guide vanes Main function: adjust the turbine load

Main Components of Turbine  Runner

Traditional runner

X-Blade runner

Main Components of Turbine  Draft tube The function: decelerate the water and recove the kinetic energy Elbow draft tube

Conical tube

Flaring tube

Straight cone

Bend

Diffuser

Campaniform tube

Main Components of Turbine  Draft tube

Francis turbine  Velocity triangle

Francis turbine  Euler’s turbine equation P  T 

P    Q  (u1cu1  u2cu 2 )

Output power from the runner

P    Q  g  Hn

Available hydraulic power

Francis turbine  Hydraulic efficiency

  Q  (u1cu1  u2cu 2 )   Q  g  Hn

u1cu1  u2cu 2  g  Hn cu 2  0

Best efficiency point

NPSH(Net Positive suction head) Bernoulli’s equation Cavitation

Atmospheric pressure head

h2  ha  H s  ( Suction head

NPSH R  a

c 22 2g

 J )  hva

NPSHR 2 m2

water vapor pressure head

For   0.53

cm2 2 u22 NPSH R  1.12  0.055 2g 2g

For   0.53

cm2 2 u22 NPSH R  1.12  (0.00426  0.0957) 2g 2g

2 2

c u b 2g 2g

NPSH R  ha  hva  H s  NPSH A Suction head H s  ha  hva  NPSH R

Francis Runner Design Design requirements (Hn,Qn,P and η)

Main dimension design Build SP, SV,GV and DT Geometry (SolidWorks) Opitimization design (BladeGen) Generate mesh (ICEM) Generate mesh (TurboGrid)

3D CFD analysis (CFX)

No

Meet the requirement ? Yes

Finish first step of the hydraulic design No

Model test Meet the requirement ?

Yes

The Hydraulic design end

Francis Runner Design  Main dimension design  Dimension of the outlet  Speed  Dimension of the inlet

Optimization design in BladeGen Meridional view

Blade angle view

Auxiliary view

Thickness view

Optimization design in BladeGen Auxiliary view Meridional view

Blade angle view

Thickness view

Francis Runner Design

Francis Runner Design  Mesh Generation

TurboGrid ATM mesh

Francis Runner Design  CFD simulation Boundary conditions: 1. Mass flow rate inlet with the vector direction 2. Non-slip wall 3. Static pressure outlet Flow state: steady Turbulence model: SST k-ω

Guide vane

Inlet Periodic boundaries

Outlet

Interface Runner blade

CFD results for Best efficiency point

CFD results for Valken runner Cross flow

CFD results for Best efficiency point

Small Hydro Power in Norway Small hydro (1-10MW) development in Norway • 1920s through1940s: 1800 hydro plants operation with a capacity of less than 1MW • 1978-1982, the Norwegian Water Resources and Energy Directorate (NVE), a potential of 10 MWH of generation from hydro plants between 1 and 10 MW. • 1990, 100 plants in operation • 1990-2000, the Norwegain goverment finaced two major hydro research and programs • 2002, a five-year plan implemented by NG, 4 million MWH by 2010

In 2008

Small Hydro Power in Norway Norwegian Water Resources and Energy Directorate (NVE) • Licensing • Finacing • Construction • Operation

Norwegian Association for Small Hydro • Established in 2001 by small hydro project owner • with support by NVE •Organize training courses

Small Turbine Partner AS (STP) • Tinfos AS • E-CO Vannkraft AS • Østfold Energi AS • Akershus Kraft AS • Energy Future Invest AS • Employees

Small Hydro Power in Norway

Small Hydro Power Plant

Reference http://en.wikipedia.org/wiki/Hydroelectricity http://www.alstom.com/power/renewables/hydro/hydro-turbines/bulb-turbines/

http://www.energi-teknikk.no/en/prosjekter/prosjektkart/ ‘Pumper & Turbiner’, Professor Hermod Brekke, Vannkraftlaboratoriet NTNU 2013 ‘The lecture of Turbomachinery’, Professor Ole G. Dahlhaug, EPT, NTNU,2011 ‘The lecture of Hydraulic design of hydraulic turbines’, Associate professor Ruofu Xiao, CAU, 2008

‘Mechanical Equipment’, Professor Arne Kjølle, NTNU, 2001

The end