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Smoke Particle Velocity Measurements in Point to Plane Corona Discharges Noureddine ZOUZOU* Eric MOREAU Gérard TOUCHARD Laboratoire d’Etudes Aérodynamiques (LEA) Poitiers University, FRANCE
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N. Zouzou 2 I.Introduction II.Experimental setup III.Electrical Properties IV.Flow Visualization and Velocity Profiles V.System Efficiency VI.Conclusions
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N. Zouzou 3 I. Introduction DC-Corona Discharges and Electrostatic Precipitation - Negative Corona + Positive Corona Ionization region Drift region Needle Grounded Electrode + + e- + Particles (dusts) + N Positive ions are directly created in the ionisation region (ions act like an extension of the active electrode) Negative ions are created in ionisation and drift regions N - + e- Electron Gas molecule Negative ion Positive ion Needle - e- - - - N + N N Corona wind
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N. Zouzou 4 I. Introduction Influence of Corona Polarity …. - Negative Corona+ Positive Corona Current pulsesStreamerTrichel Discharge progressContinuousNon-continuous Ozone generationLowHigh What about: Ionic wind velocity (magnitude and profile) ? System Efficiency (Power output / Power input)?
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N. Zouzou 5 II. Experimental Setup r axis z axis 40 kV 10-50 mm HV supply A 2M Laser sheet Camera acquisition Glass box: V=25 25 25 cm 3 Needle curvature: 100 µm PIV system: LAVISION
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N. Zouzou 6 III. Results Electrical Properties - Negative Corona + Positive Corona Corona current Air > Air + particles Corona current Negative > Positive Flashover voltage Negative > Positive
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N. Zouzou 7 IV. Results Flow Visualization and Velocity Profiles Needle Plane + Positive Corona (40mm,10kV)
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N. Zouzou 8 IV. Results Flow Visualization and Velocity Profiles + Positive Corona (40mm,10kV)
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N. Zouzou 9 IV. Results Flow Visualization and Velocity Profiles - Negative Corona + Positive Corona Velocity profile is asymmetric Velocity 0 m/s near the electrodes Particle acceleration distance is slight ( 3mm)
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N. Zouzou 10 IV. Results Flow Visualization and Velocity Profiles - Negative Corona + Positive Corona Impacting jet is non-conic Velocity peak magnitude Positive > Negative (mobility) Velocity peak width Negative > Positive (space charge)
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N. Zouzou 11 IV. Results Flow Visualization and Velocity Profiles - Negative Corona + Positive Corona Velocity can reach 6 m/s Velocity maximum Negative > Positive (current limitation) Velocity square root of the current
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N. Zouzou 12 IV. Results Flow Visualization and Velocity Profiles B is proportional to the gap distance B value Positive > Negative (mobility)
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N. Zouzou 13 V. Results System Efficiency Power Input maximum Negative > Positive Velocity cube root of input power
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N. Zouzou 14 V. Results System Efficiency r axis z axis S1S1 S3S3 S2S2 Mechanic power associated with a domain (D) Stationary regime If (D) is cylindrical in shape Electro-kinetic conversion efficiency
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N. Zouzou 15 V. Results System Efficiency At low voltages Efficiency At high voltages Negative Efficiency Positive Efficiency
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N. Zouzou 16 IV. Conclusion Corona current with voltage, however it with the presence of incense particles The axial and radial profiles of the velocity show some differences associated with the discharge polarity (Velocity 6 m/sec) Velocity (current) 1/2, and Velocity (Input Power) 1/3 Electro-kinetic conversion efficiency 0.2 %, it with Negative applied voltage
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