Post on 05-Mar-2018
A BRIEF INTRODUCTION:Design Freedom, mechanical Advantages and Economic Benefits of
The New Updraft-Divergent-Flow Hydroturbine (K-Turbine)
David T. KaoProfessor & Dean Emeritus of Engineering College, Iowa State University
November, 2009
TECHNICAL BRIEFING
2/17/2011 D.T.Kao 2
Existing Hydro-Turbine Types
3
High Head Mid-High Head
Low-Mid Head Low Head-Bulb
P = η x 9.8 x Q x H
P = Out put (kW)Q = Flow (CMS)H = Head (M)η = Efficiency
= 1 – (Friction & Turbulent Losses)
Elements of Conventional Turbines
4
Francis Turbine Propeller Turbine
3-Gorges’ Runner
Complex draft tube
Wicket Gates Control
2/17/2011 5
The Key Design DifferencesBetween the Conventional (a) & the Updraft (b) Turbines
To a long draft tube (adds 25% cost)
Inflow
Wicket gates: Major causes of fish injury
High pressure shaft seal: need frequent maintenance
Runner
High water pressure zone
Negative pressure zoneMajor causes of fish mortality
Inflow
Does not need a draft tube
(b) Updraft design: light, simple & inexpensive; environmentally sound & fish friendly
D. T. Kao
(a) Downdraft design: heavy, complex & expensive; and can cause heavy fish injury & mortality
(a) (b)
To Generator
OutflowOutflow
Outflow
The New System Features Four Crucial Design Innovations:
1) An updraft flow arrangement; 2) A vertical pressure-balanced turbine flow
control valve to replace conventional closely spaced wicket gates;
3) A divergent runner flow chamber to recover kinetic energy (KE) without using the costly draft tube; and
4) Turbine flow exits at the free surface in the tailwater terrace to aerate and improve exit flow water quality.
2/17/2011 D.T.Kao 6
2/17/2011 D. T. Kao
Advantage: Easy Installation -- The new K-turbine is easy to install and maintain
The Fundamental Fluid Mechanics Principle: The energy input to both turbines, for the same flow, Q, and head, H, is the same regardless of the turbine flow direction.
Conventional downdraft flow Turbine require costly draft tube
HQ
Innovative K-Turbine can be used for new power station or to retrofit on existing dams
H
Q
7
2/17/2011 8
Self KE Recovery & Aeration-- Saves system cost & improves downstream water quality
Gradually decreasing flow velocity in the divergent turbine runner chamber (CFD results) results in recovering 90% or more KE
The residual kinetic energy (KE) generates flow aeration & air entrainment actions (shown during the test) to improve downstream water quality
D. T. Kao
2/17/2011
Open Flow Passage With No Cavitation – Minimizes injure & mortality of passing fish
9D. T. Kao
CFD simulation shows less grinding and striking injures to the passing fish
No negative cavitation pressure to cause fish mortality due to internal injury
2/17/2011 10
Experimental Results shows Safe fish passage through the New Turbine with no Negative (Cavitation) Pressure
Experiment Set-up
2/17/2011 11
Flow Pattern and Efficiency
Outflow
Inflow
Design flow Q = 25.35 CMSDesign head H = 15 MTurbine Diameter = 2.04 MPeak Eff. = 88.2%
Arrows shoe 3-D velocity vectors along the blade (CFD flow pattern analysis)
-- Parallel velocity vector indicates smooth flow that helps to eliminate blade vibration & reduced energy loss
D. T. Kao
[ ]
D = 20.3 cm (8 inches)H = 1.38 MQ = 0.048 CMSPeak Eff . = 86.15 %Analytical & experimental results
show that the new hydroturbine is highly efficient even at micro size
Projected Performance Comparison
2/17/2011 D.T.Kao 12
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Relative Power
Rel
ativ
e Ef
ficie
ncy
Propeller Turbine (data) Kaplan Turbine (data) Kao Turbine (CFD)
Summary on The Competitive Advantages of the K-Turbine
2/17/2011 D.T.Kao 13
Saves 35 to 66% station cost
3 to 8% more efficient
Easier to maintain
Improves water quality
Minimizes fish injury and mortality
Prototype 7-kW K-Turbine andCFD Analysis Results
2/17/2011 D.T.Kao 14
Computational Fluid-Dynamics (CFD) analysis results on Pressure distribution on the pressure-side of the K-turbine runner blade.
CFD analysis results on streamline pattern inside the spiral case of the K-turbine.
Prototype 7-kW K-turbine.
MARKET POTENTIAL
2/17/2011 D.T.Kao 15
The Opportunity:Huge Untapped Global Hydropower Resources
79% of global hydropower resources remain untapped (~ 1,760,000 MW) The equivalent of approximately 3,000 nuclear power plants
16
78%93%
67%
31%25%
30%
Relative Size of Reserves by Continent% Untapped Reserves by Continent
Source: International Hydropower Assoc.
The Problem: Lack of Technology to DevelopPico to Small Hydropower Resources
17
Less than 15% untapped resources in large-hydro (>1,000MW) sites
!More than 85% untapped resources in pico to medium size sites (*)
3 gorges dam, 22,500 MW
Hoover dam, 2,080 MW
------------------(*) Pico (<10kW), Micro (<100kW), Mini (<1MW), Small (<25MW), and Medium scale (<250MW) hydropower sites
Shortcomings of Existing Hydropower Turbine Technology
The Idaho National Laboratory, US DOE web declares: “Current hydropower technology, while essentially emission-free, can have undesirable environmental effects, such as fish injury and mortality from passage through turbines, as well as detrimental changes in the quality (dissolved gases) of downstream water.”
18
There is great demand for Innovative Eco-environmental friendly turbine technology!
2/17/2011 19
We Call Those
“The 5-E Advantages”:
D. T. Kao
EconomicalEfficientEasyEcologically friendlyEnvironmentally sound
Approximate Application Ranges of Various Type Hydro-Turbines
2/17/2011 D. T. Kao 20
Micro- Mini- Small- Medium- Large-turbines
Turbine Output (kW)| | | | | |
1 10 100 1,000 10,000 100,000
1,000
100
10
1
__
__
__
__
Water Head (M)
Pico-
Conventional Francis-turbine and Kaplan-turbine
Innovative Kao-turbine
Scale down Conventional turbine
K-Turbine Has Broad Application Ranges and Is Highly Competitive
Applicable Ranges• Water Head: 1 to 80 M• Power Output: kW to MW
Competitiveness• Environmental Advantages• Cost Less• Easy to Install, Operate, and
Maintain
2/17/2011 D.T.Kao 21
kW - prototype
MW- CAD illustration
1 ~ 25 MW
Market Development Strategy- Start small & grow
22
Estimate Pico- Market: 4 Million Units
Source: IT Power of UK, 2006
Pico- to Micro-
Mini- to Small-
Medium-to Large
2/17/2011 D.T.Kao
kW unit
Easy Installation on New or Existing Dams Example: Potential hydropower generation from irrigation water release
with its energy being currently mechanically dissipated
2/17/2011 D. T. Kao 23
Existing dam
Enough power for 1.3 MW with 2 units
Connecting pipes
The New K-Turbine Can Effectively Compete in Exiting & New Market Categories: New power stations Old station turbine replacement Retrofitting on existing dams Distributed peak-power supply Low-head large-flow market needs Environmental flow power generation Energy storage for solar & wind power Remote areas basic energy supply needs
242/17/2011 D.T.Kao
Thank you! For licensing information,
please contact licensing@iastate.edu