Post on 20-Jan-2016
Jerzy Mizeraczyk
XII INTERNATIONAL CONFERENCEXII INTERNATIONAL CONFERENCEONON
ELECTROSTATIC PRECIPITATIONELECTROSTATIC PRECIPITATION
NuernbergNuernberg
May 9 – 13, 2011May 9 – 13, 2011
CeCentre for Plasma and Laser Engineeringntre for Plasma and Laser EngineeringThe Szewalski Institute of FluidThe Szewalski Institute of Fluid--Flow MachineryFlow Machinery
Polish Academy of SciencesPolish Academy of SciencesGdańsk, PolandGdańsk, Poland
PIV MEASUREMENTSPIV MEASUREMENTS
OF ELECTROHYDRODYNAMIC FLOW IN ESPsOF ELECTROHYDRODYNAMIC FLOW IN ESPs
MotivationMotivation of laser investigations of flow patterns of laser investigations of flow patternsin in electrostatic precipitatorelectrostatic precipitatorss
Interest in improving electrostatic precipitator (ESP) collection of fine particles (micron and submicron sizes).
How does the EHD flow caused by the presence of electric field and charge in ESPs influence the particle precipitation process?
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OUTLINEOUTLINE
Laser flow visualization • Principles of laser flow visualization
Particle Image Velocimetry (PIV)• Principles of of 2-dimensional (2D) and 3-dimensional (3D) Particle Image Velocimetry• Products of PIV (flow velocity field, flow streamlines, vorticity map) Example of PIV measurements in a spike-to-plate electrostatic precipitator (ESP):• PIV measurement of the dust particle flow structures•Structures of the dust particle deposits• Correlation between the dust particle flow structures and the dust particle deposit structures
Conclusions
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PRINCIPLEPRINCIPLEOF PARTICLE IMAGE VELOCIMETRY (PIV)OF PARTICLE IMAGE VELOCIMETRY (PIV)
•Flow seeded with particles following the motion of the flow
•Light source for illumination of the flow
•Camera to capture 2 images of the motion of the seed particles
v = S / (t2 – t1)4
2 consecutive CCD images
2D PARTICLE IMAGE VELOCIMETRY - PRINCIPLE 2D PARTICLE IMAGE VELOCIMETRY - PRINCIPLE
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EXPERIMENTAL SETUP FOR 2D PIV MEASUREMENTS EXPERIMENTAL SETUP FOR 2D PIV MEASUREMENTS
The standard PIV equipment (Dantec PIV 1100):
- a twin second harmonic Nd-YAG laser system capable of changing t = t2 – t1
- cylindrical telescope to produce a laser beam sheet- CCD camera, tmin = 2 s,
1018x1018 pixels- image processor- PC computer 6
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EXPERIMENTAL SETUP FOR 3D PIV MEASUREMENTSEXPERIMENTAL SETUP FOR 3D PIV MEASUREMENTS
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Products of PIV (flow velocity field, flow streamlines, vorticity map)Products of PIV (flow velocity field, flow streamlines, vorticity map)
Time-averaged flow streamlines in the ESP
Vp = 0.9 m/sFlow streamlines not much disturbed in
comparison with no voltage flow streamlines. Some disturbances near the plate electrodes in the discharge region.
Vp = 0.6 m/sStronger disturbances than for the Vp=0.9 m/s,
vortices in the discharge region.
Vp = 0.2 m/sStrong vortices in the discharge region. Pair of
vortices placed 100 mm dowstream the wire electrode block the flow in the ESP duct centre.
Laser flow visualization and PIV - exampleLaser flow visualization and PIV - exampleStudy of the dust particle flow structures in a wire-plate ESP – laboratoryStudy of the dust particle flow structures in a wire-plate ESP – laboratory
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Flow velocity field in the ESP model at a main flow velocity of 0.6 m/s. Positive polarity, voltage 24 kV.
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LASER FLOW VISUALIZATION AND LASER FLOW VISUALIZATION AND PIVPIV IN ESP IN ESP
Study of the dust particle flow structures in 7-electrode wire ESP - laboratory
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Primary flow velocity: 0.6 m/s (Reynolds number 4000)
Flow gas: ambient air Dust: TiO2 particles (2D PIV) or cigarette smoke (3D PIV)
Operating voltage: 0 – 28 kV (positive polarity)
Discharge current: 0 – 210 A (Ehd number up to 3 * 108)
Spike electrode:12 spikes200 mm long
1 mm thickness
14 measurement planes:
A, B, C - longitudinal
E - N - transverse
EHD FLOW PATTERNS IN A SPIKE-PLATEEHD FLOW PATTERNS IN A SPIKE-PLATE ESP ESPUNDER POSITIVE AND NEGATIVE POLARITIES UNDER POSITIVE AND NEGATIVE POLARITIES
Side view
V [m/s]
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EHD FLOW PATTERNS IN A WIDE SPACINGEHD FLOW PATTERNS IN A WIDE SPACING SPIKE-PLATESPIKE-PLATE ESP ESPUNDER POSITIVE AND NEGATIVE POLARITIES UNDER POSITIVE AND NEGATIVE POLARITIES
IMAGE OF THE PRECIPITATED DUST
Dust
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EHD FLOW PATTERNS IN A SPIKE-PLATEEHD FLOW PATTERNS IN A SPIKE-PLATE ESP ESPUNDER NEGATIVE POLARITUNDER NEGATIVE POLARITYY
FLOW PATTERN AND IMAGE OF THE PRECIPITATED DUST
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U = -27.4 kVI = 260 A
Plane A
Dust
EHD FLOW PATTERNS IN A SPIKE-PLATEEHD FLOW PATTERNS IN A SPIKE-PLATE ESP ESPUNDER NEGATIVE POLARITUNDER NEGATIVE POLARITYY
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3D PIV MEASUREMENT OF VELOCITY X-COMPONENT
EHD FLOW PATTERNS IN A SPIKE-PLATEEHD FLOW PATTERNS IN A SPIKE-PLATE ESP ESPUNDER POSITIVE POLARITUNDER POSITIVE POLARITYY
Side view
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V [m/s]
Front view
NARROW ESP WITH LONGITUDINAL WIRE ELECTRODENARROW ESP WITH LONGITUDINAL WIRE ELECTRODE
X in mm
• Air flow generated by DC corona discharge
• Electrode configuration determines the flow direction
• Flow velocity up to 1 m/s
• Flow rate up to 630 cm3/s
EHD gas pump features:Velocity profiles at the exit section of EHD gas pump
Velocity profile at the exit of EHD gas pump (3D PIV)
EHD gas pump overviewFlow generated by EHD gas pump
PIV measurement
EHD GAS PUMPEHD GAS PUMP
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Length of HV and grounded electrodes: 50 mmLength of floating interelectrodes: 45 mmHigh voltage electrodes width: 15 mmHV and FL interelectrodes in optimum position
Floating interelectrodes width: 3 mmFloating to grounded electrode distance: 6 mm Grounded electrodes width: 3 mm Grounded to floating electrode distance: 13 mm
Dielectric: glass plate – 2 mm thick High voltage: Upp = 32 kV, f = 1.5 kHz
Airflow velocity m/s
Time-averaged streamlines of a airflow inducedby multi DBD actuator with floating saw-like interelectrodes
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EXPERIMENT - CALCULATIONEXPERIMENT - CALCULATIONFlow patterns in wire-plate ESP for various dust densities
Experiment Calculation – K. Adamiak & P. Atten
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Flow patterns in wire-plate ESP for various Ehd/Re2 ratio
Calculation – Chun & ChangExperiment
Ehd / Re2 – a measure of the EHD disturbance of the primary flow
Ehd = I t * L3 / (A * * g2 * i) Re = U0 * L / g
EXPERIMENT - CALCULATIONEXPERIMENT - CALCULATION
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LASER FLOW VISUALIZATION IN INDUSTRIAL ESPLASER FLOW VISUALIZATION IN INDUSTRIAL ESP
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LASER SYSTEM FOR FLOW VISUALIZATION LASER SYSTEM FOR FLOW VISUALIZATION ON THE TOP OF INDUSTRIAL ESPON THE TOP OF INDUSTRIAL ESP
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All four sections ON, hammering at t = 0 in section 4
LASER FLOW VISUALIZATION IN INDUSTRIAL ESPLASER FLOW VISUALIZATION IN INDUSTRIAL ESP
Light-green spots – dust in the ESPYellow lines – flow streamlinesdeduced from the flow images
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CONCLUSIONSCONCLUSIONS
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Laser visualization and Particle Image Velocimetry proved to be useful instruments in studying flow and collection phenomena in electrostatic precipitators
Owing to the PIV measurement a correlation between structures of the particle flow and particle deposit in the spike-plate ESP was found. The particle flow structures explain how the particle deposit structures are formed.
Basing on the PIV results we found a correlation between the particle flow structures and the total collection efficiency for the various configurations of spike-type electrode. Negative effect for downstream-directed one-sided electrode.
Centre for Plasma and Laser EngineeringInstitute of Fluid Flow Machinery
Polish Academy of Sciences, Gdańsk, PolandJ. Mizeraczyk, J. Podliński, M. Kocik, M. Dors, J. Dekowski, A. Niewulis
COLLABORATORSCOLLABORATORS
Department of Electrical and Electronic EngineeringOita University, Japan
T. Ohkubo, Y. Nomoto, S. Kanazawa
Department of Engineering Physics McMaster University, Hamilton, Ontario, Canada
J.-S. Chang, D. Brocilo, K. Urashima, Y.N. Chun, A.A. Berezin
Laboratoire d'Electrostatique et de Matériaux DiélectriquesUniversité Joseph Fourier, Grenoble, France
P. Atten
Laboratoire d’Etudes AérodynamiquesUniversité de Poitiers, France
G. Touchard
Department of Ecological EngineeringToyohashi University of Technology, Japan
A. Mizuno
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