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Design Optimisation and Characterisationof a Crossflow Turbine
ByC.S. Kaunda
University of Dar es Salaam/NTNU02nd May, 2012
SupervisorsProf. Kimambo - UDSM
Prof. Nielsen - NTNU
ByC.S. Kaunda
University of Dar es Salaam/NTNU02nd May, 2012
SupervisorsProf. Kimambo - UDSM
Prof. Nielsen - NTNU
Outline of Paper Presentation• Introduction: Link between energy and
development: Scenario in sub-Saharan Africa (SSA)• Rural Electricity Supply Scenario in SSA• Microhydropower Technology – Status, Potential in
and Challenges in SSA• Crossflow Turbine Technology and
Microhydropower in SSA• Performance Challenges of Crossflow Turbines• Areas of Improvement• Conclusions
• Introduction: Link between energy anddevelopment: Scenario in sub-Saharan Africa (SSA)
• Rural Electricity Supply Scenario in SSA• Microhydropower Technology – Status, Potential in
and Challenges in SSA• Crossflow Turbine Technology and
Microhydropower in SSA• Performance Challenges of Crossflow Turbines• Areas of Improvement• Conclusions
Energy and Development• Modern energy supply such as electricity supports
achievement of MDGs.• Social and economic as well as environmental
management activities are supported bysustainable energy supply
• SSA (except South Africa) faces acute shortage ofmodern energy.
• Electricity scenario in most countries ischaracterized by low consumption, small generationcapacity/million people, unreliability of powersupply and low electricity supply levels.
• Modern energy supply such as electricity supportsachievement of MDGs.
• Social and economic as well as environmentalmanagement activities are supported bysustainable energy supply
• SSA (except South Africa) faces acute shortage ofmodern energy.
• Electricity scenario in most countries ischaracterized by low consumption, small generationcapacity/million people, unreliability of powersupply and low electricity supply levels.
Electricity access in 2009 - Regionalaggregates (IEA, 2010)
Region
Populationwithout
electricity
millions
Electrification rate
%
Urbanelectrificatio
n rate%
Ruralelectrificatio
n rate%
Africa 587 41.8 68.8 25.0
North Africa 2 99.0 99.6 98.4
Sub-Saharan Africa 585 30.5 59.9 14.2
Developing Asia 675 81.0 94.0 73.2
China & East Asia 182 90.8 96.4 86.4
South Asia 493 68.5 89.5 59.9
Latin America 31 93.2 98.8 73.6
Middle East 21 89.0 98.5 71.8
Developing countries 1,314 74.7 90.6 63.2
World* 1,317 80.5 93.7 68.0
Region
Populationwithout
electricity
millions
Electrification rate
%
Urbanelectrificatio
n rate%
Ruralelectrificatio
n rate%
Africa 587 41.8 68.8 25.0
North Africa 2 99.0 99.6 98.4
Sub-Saharan Africa 585 30.5 59.9 14.2
Developing Asia 675 81.0 94.0 73.2
China & East Asia 182 90.8 96.4 86.4
South Asia 493 68.5 89.5 59.9
Latin America 31 93.2 98.8 73.6
Middle East 21 89.0 98.5 71.8
Developing countries 1,314 74.7 90.6 63.2
World* 1,317 80.5 93.7 68.0
Electricity Consumption Levels (World Bank, 2009)
4532
Sub-Saharan Africa Electricity Consumption Level (kWh/Capita)
Electricity Consumption Level (kWh/Capita)
20291
1503
27151 46
922
265147 85
453
1576
121 86 111
635
1023
Electricity Access Levels in SouthernAfrica in 2005 (World Bank, 2008)
75
80
87
(c) Electricity Access Levels in Southern Africa (2005)
Urban Electricity Access Level (%) Rural Electricity Access Level (%)
26
45
16
23
2926
45
4
9
2 1 1 2
12
50
3
8
Angola Botswana DRC Lesotho Malawi Mozambique Namibia South Africa Zambia Zimbabwe
Microhydropower Technology• Hydropower technology using small-scale plants is well matured
(Khennas and Barnett, 2000; Kaldellis et al, 2005) and has been inuse for many years ago.
• Microhydropower is a subset in Small Hydropower (SHP)categorization: No international agreement upper level of SHP .Most EU (10 MW), SA (10 MW), USA (30MW), Brazil (30MW), China (50 MW)
• Microhydropower (MHP): Less than 100 kW mostly.• MHP used for both: electricity generation and mechanical power.• In SSA, technology brought by missionaries and early tea planters.• Ideal for rural electrification: rural institutional facilities such as
schools, health centres and markets• Considered renewable, but climate change (droughts and
desertification) affects MHP availability during particular monthsof the year.
• Hydropower technology using small-scale plants is well matured(Khennas and Barnett, 2000; Kaldellis et al, 2005) and has been inuse for many years ago.
• Microhydropower is a subset in Small Hydropower (SHP)categorization: No international agreement upper level of SHP .Most EU (10 MW), SA (10 MW), USA (30MW), Brazil (30MW), China (50 MW)
• Microhydropower (MHP): Less than 100 kW mostly.• MHP used for both: electricity generation and mechanical power.• In SSA, technology brought by missionaries and early tea planters.• Ideal for rural electrification: rural institutional facilities such as
schools, health centres and markets• Considered renewable, but climate change (droughts and
desertification) affects MHP availability during particular monthsof the year.
MHP Potential in SSACountry Identified Potential Declaration of Source
Malawi 7.4 MW Kaunda and Kimambo, 2011
Tanzania 185 MW Kabaka andGwang’ombe, 2007
Mozambique Over 1000 MW Hankins, 2009
Zimbabwe 120 MW Government of Zimbabwe,2009
Rwanda Over 300 sites identified.Total power potential notknown
Rwanda Utilities RegulatoryAgency , 2009
Rwanda Over 300 sites identified.Total power potential notknown
Rwanda Utilities RegulatoryAgency , 2009
Ghana 21 sites identified withpower potential rangingfrom 4 to 325 kW
Government of Ghana,2010
Kenya Over 3000 MW Government of Kenya, 2011
Uganda 210 MW Uganda Energy RegulatoryAuthority, 2007
Nigeria Over 3500 MW Sambo, 2009
MHP Application status in SSACountry SHP Installed Capacity Declaration of Source
Ethiopia 80 MW In Conference Proceedings:Ministerial Conference onWater for Agriculture andEnergy , Libya, 2008.
Kenya 15 MW Kipyego, 2011
Uganda 18 MW Uganda ElectricityRegulatory Agency, 2009Uganda ElectricityRegulatory Agency, 2009
Rwanda 6.5 MW Rwanda Utilities RegulatoryAgency , 2009
Tanzania 5.4 MW Kaunda et al, 2012.
South Africa 68 MW Renewable Energy inemerging and developingcountries Project: CountryReport, South Africa, 2006
Malawi 1.3 MW Kaunda and Kimambo, 2011
Zimbabwe 1.4 MW Tinarwo, 2009
Basic components and arrangement of atypical micro hydropower system , RoR
Weir
Penstock
Power canalForebay
Main River
Power houseElectromechanical system
Transmission systemto Load
Tail racewater
Main River
MHP Mechanical Power Generatingequipment - Turbine
• Grouped into Reaction & Impulseturbines
• Can be low, medium and high head• Francis, Kaplan, Propeller are reaction
types• Pelton Wheel, Turgo and Crossflow? Are
impulse type• Efficiencies high except Crossflow
• Grouped into Reaction & Impulseturbines
• Can be low, medium and high head• Francis, Kaplan, Propeller are reaction
types• Pelton Wheel, Turgo and Crossflow? Are
impulse type• Efficiencies high except Crossflow
Turbine Performance Curves (IPCC, 2011)
Crossflow Turbine Application range inMHP (Southeast Power Ltd, 2008)
Crossflow Turbine (CFT)• Relatively cheap as compared to others: per kW of installed
capacity, CFT has lower cost.• CFT runner relatively simple to manufacture – most of the local
workshops in developing countries have facilities to fabricate one.• CFT Impulse type of turbine as such able to handle poor water
quality in power production• CFT has ability to maintain optimum efficiency levels for a varied
flow• CFT Common in developing countries S.E Asia
(India, Nepal, Afghanistan et al).• CFT Technology is now becoming popular in some SSA countries
such TZ and MW. In TZ, most of the recorded MHP are of CFT.• In Tanzania, UDSM, Arusha technical college are involved in the
fabrication of the technology.• In Malawi, The Polytechnic and Malawi Industrial Research and
Technology Development Centre also involved in the fabrication.
• Relatively cheap as compared to others: per kW of installedcapacity, CFT has lower cost.
• CFT runner relatively simple to manufacture – most of the localworkshops in developing countries have facilities to fabricate one.
• CFT Impulse type of turbine as such able to handle poor waterquality in power production
• CFT has ability to maintain optimum efficiency levels for a variedflow
• CFT Common in developing countries S.E Asia(India, Nepal, Afghanistan et al).
• CFT Technology is now becoming popular in some SSA countriessuch TZ and MW. In TZ, most of the recorded MHP are of CFT.
• In Tanzania, UDSM, Arusha technical college are involved in thefabrication of the technology.
• In Malawi, The Polytechnic and Malawi Industrial Research andTechnology Development Centre also involved in the fabrication.
Crossflow turbine
Nozzle
Runner
Draft tube
Guide vane
Crossflow Turbine Runner
Runner blades
Bearing housing
Shaft
Bearing housing
Crossflow Turbine (CFT)• Due to its low efficiency levels, most of the turbine
manufacturing companies did not embark on improvingits performance studies for wide scale application.
• Performance studies on the CFT are relatively fewcompared to other types of turbines: CFT are lessefficient turbines (less than 80% practically possible)
• CFT poor performance is due to poor its poor internalflow profile in the runner.
• Studies concentrated on optimising the geometricdimensions of physical design parameters and varyingperformance.
• Due to its low efficiency levels, most of the turbinemanufacturing companies did not embark on improvingits performance studies for wide scale application.
• Performance studies on the CFT are relatively fewcompared to other types of turbines: CFT are lessefficient turbines (less than 80% practically possible)
• CFT poor performance is due to poor its poor internalflow profile in the runner.
• Studies concentrated on optimising the geometricdimensions of physical design parameters and varyingperformance.
Crossflow Turbine (CFT)In the design and optimization of the turbine, it is
important to evaluate :• How does the internal flow pattern affect the
hydraulic efficiency in the turbine?• How does the fluid velocity and pressure
distribution influence the turbine performance for agiven flow and head?
• What are the effects of changing geometric designparameters to the turbine performance?
In the design and optimization of the turbine, it isimportant to evaluate :
• How does the internal flow pattern affect thehydraulic efficiency in the turbine?
• How does the fluid velocity and pressuredistribution influence the turbine performance for agiven flow and head?
• What are the effects of changing geometric designparameters to the turbine performance?
Crossflow Turbine (CFT)• Flow profile can be characterized using Navier- Stokes
equations
• Flow in CFT is quite complex, 3d-dimensiona; and two phase.• Characterization and design optimization done by using CFD.
• Flow profile can be characterized using Navier- Stokesequations
• Flow in CFT is quite complex, 3d-dimensiona; and two phase.• Characterization and design optimization done by using CFD.
CFD Design Procedure
Conclusions• Capacity for CFT to be used in rural electricity
supply is high in SSA• Need to look at addressing technological issues that
hinder MHP development in the region. In this casesupporting local turbine manufactures with efficientdesign models will help.
• CFT design need to be looked at optimization theinternal flow profile. This may define the optimumsize of the turbine for particular site (head and flowrate) and flow conditions.
• Capacity for CFT to be used in rural electricitysupply is high in SSA
• Need to look at addressing technological issues thathinder MHP development in the region. In this casesupporting local turbine manufactures with efficientdesign models will help.
• CFT design need to be looked at optimization theinternal flow profile. This may define the optimumsize of the turbine for particular site (head and flowrate) and flow conditions.
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