The School of Mechanical Engineering  Current Trends in the Application of  Atmospheric Plasma for the Improvement  of Win...
The School of Mechanical EngineeringWind Energy• Clean alternative source of power• Currently competitive with fossil powe...
The School of Mechanical EngineeringLoads on Wind Turbines• Inertial forces due to dead weight of rotor blades  which are ...
The School of Mechanical EngineeringAerodynamic Blade Loading    • Two velocity components – wind and blade motion    • Re...
The School of Mechanical EngineeringBlade Separation and Stall• Lift coefficient varies with angle of attack. Should be as...
The School of Mechanical EngineeringSeparation Control• Wind turbines designed to operate in specific ranges of  wind spee...
The School of Mechanical EngineeringLoad Reduction - Blade Section Aerodynamics• Minimize fatigue life of system due to ch...
The School of Mechanical EngineeringPlasma Actuators• Standard Dielectric Barrier Discharge (DBD) Actuator  configuration ...
The School of Mechanical EngineeringDBD Actuator Physics• Dielectric material retains more electrons than the  electrode m...
The School of Mechanical EngineeringMassless Wall Jets• DBD actuators modify fluid flow characteristics by  generating mas...
The School of Mechanical EngineeringDBD Actuators for Flow Separation• DBD actuators were shown to     – energize flow nea...
The School of Mechanical EngineeringSummary• DBD actuators are an effective means of separation and  stall control• Feasib...
The School of Mechanical Engineering Acknowledgements •       Electrical and Mechanical Engineering Workshop at the Univer...
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ICWES15 - Current Trends in the Application of Atmospheric Plasma for the Improvement of Wind Turbine Efficiency through Separation Control. Presented by Ms Amelia Greig, Adelaide SA

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ICWES15 - Current Trends in the Application of Atmospheric Plasma for the Improvement of Wind Turbine Efficiency through Separation Control. Presented by Ms Amelia Greig, Adelaide SA

  1. 1. The School of Mechanical Engineering Current Trends in the Application of Atmospheric Plasma for the Improvement of Wind Turbine Efficiency through Separation Control Authors: Mei Cheong Dr. Maziar Arjomandi Presenter: Amelia Greig 21st July 2011
  2. 2. The School of Mechanical EngineeringWind Energy• Clean alternative source of power• Currently competitive with fossil power• Major limitation comes from adverse aerodynamic loadings shortening lifespans Wind turbine on Rottnest Island Courtesy of Caniluna Pty Ltd Price comparison between wind and traditional power. Courtesy of UTS2
  3. 3. The School of Mechanical EngineeringLoads on Wind Turbines• Inertial forces due to dead weight of rotor blades which are periodic and unsteady• Aerodynamic loads – Uniform, steady airflows generate time-independent steady- state loads – Steady but spatially non-uniform airflows cause cyclic loadings – Turbulent airflows cause non-periodic stochastic loads3
  4. 4. The School of Mechanical EngineeringAerodynamic Blade Loading • Two velocity components – wind and blade motion • Resultant gives optimal angle of attack – Generally between 12o-15o • Wind gusts up to 25%, alter required angle of attack Turbine velocity components and resulting angle of attack4
  5. 5. The School of Mechanical EngineeringBlade Separation and Stall• Lift coefficient varies with angle of attack. Should be as high as possible for efficient turbine operation• Wind gusts cause separation and stall to occur if angle of attack increases past maximum levelsLift coefficient of turbine blade with angle of attack Change in airflow with angle of attack Adapted from http://www.sportpilot.org5
  6. 6. The School of Mechanical EngineeringSeparation Control• Wind turbines designed to operate in specific ranges of wind speeds• Outside this range, adverse aerodynamic loads occur predominantly due to separation control• Turbine blade loads controlled through: – Flow velocity through variable speed rotor – Blade length – Blade incidence angle through variation of blade pitch – Blade section aerodynamics 6
  7. 7. The School of Mechanical EngineeringLoad Reduction - Blade Section Aerodynamics• Minimize fatigue life of system due to changes in wind direction and speed• Passive control – Control through adaptation of aero-elastic responses of blades and stall regulation• Active control – Control through adjustment of aerodynamic properties and pitch angles of blades Photos from http://www.lmwindpower.com and http://en.wikipedia.org7
  8. 8. The School of Mechanical EngineeringPlasma Actuators• Standard Dielectric Barrier Discharge (DBD) Actuator configuration Schematic configuration for DBD actuator• Plasma generated by applying an electric field to sustain electron-ion pairs Electron movement: a) negative half-cycle, b) positive half-cycle8 Adapted from Cheong et al. 2010
  9. 9. The School of Mechanical EngineeringDBD Actuator Physics• Dielectric material retains more electrons than the electrode material resulting in an asymmetric flow pattern• Induced airflow, called ‘Ionic Wind’ results Plasma induced airflow and response force Plasma discharge Adapted from Cheong et al. 20109
  10. 10. The School of Mechanical EngineeringMassless Wall Jets• DBD actuators modify fluid flow characteristics by generating massless wall jets in the boundary layer of the flow• Introduction of these jets injects momentum into retarded boundary layers to delay separation or even reattaching separated flow Lift coefficient with and without actuator1 Adapted from Nelson et al., 20080
  11. 11. The School of Mechanical EngineeringDBD Actuators for Flow Separation• DBD actuators were shown to – energize flow near locations of separation (Huang et al. 2006) – increase stall angle and delaying leading-edge separation (Orlov et al. 2007, Post & Corke 2004) – improve lift cycle by controlling dynamic stall vortices (Post & Corke 2006) Adapted from Post & Corke, 200611
  12. 12. The School of Mechanical EngineeringSummary• DBD actuators are an effective means of separation and stall control• Feasible method of load control for wind turbine blades• Advantages over conventional methods of load control: High frequency response Do not introduce parasitic drag Low power consumption• Further investigations to implement DBD actuators on wind turbines highly valuable12
  13. 13. The School of Mechanical Engineering Acknowledgements • Electrical and Mechanical Engineering Workshop at the University of Adelaide • The Sir Ross and Sir Keith Smith Fund DisclaimerResearch undertaken for this report has been assisted with a grant from the Smith Fund (www.smithfund.org.au). The support is acknowledgedand greatly appreciated. The Smith Fund by providing for this project does not verify the accuracy of any findings or any representation containedin it. Any reliance in any written report or information provided to you should be based solely on your own assessment and conclusions. The SmithFund does not accept any responsibility or liability from any persons, company or entity that may have relied on any written report orrepresentations contained in this report if that person, company or entity suffers any loss (financial or otherwise) as a result.

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