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Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
1
Particle ControlInnovation of Combustion Particle Control Technologies
Assisted by Numerical Modelling
Donato Rubinetti 1 Josef Wüest 2
1Institute of Thermal and Fluid EngineeringUniversity of Applied Sciences and Arts Northwestern Switzerland
2Institute of Bioenergy and Resource EfficiencyUniversity of Applied Sciences and Arts Northwestern Switzerland
Particle Control
DonatoRubinetti
Introduction
Technology
Pellet Burner
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
2
IntroductionIndustrial Relevance
• Cleaning of exhaust gases• Promote renewable energy sources• Electric filter producer OekoSolve
Particle Control
DonatoRubinetti
Introduction
Technology
Pellet Burner
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
3
IntroductionPellet Burner
Burner Unit
Heat Exchanger
+ Turbulators
Exhaust
Design Area
from: Liebi LNC LPK Pellet Burner Technical Documentation, 30.08.2011, www.liebilnc.ch
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
4
Particle TrajectoriesEntire study overview and topic definition
Color legend:particle charges in number of elementary charges
Features
1 CFD
2 Electrostatics
3 Particle charging processes
4 Particle deposition study
5 Geometry variations
6 Parameter variations
7 ...
Here: Focus on improvingair ionization processes
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
5
Coupled Physics
ESP-Geometry
Flow Electric Field
Particles
Drag Force
Particle-Air-Coupling
Corona-Wind
Ion-Air-Coupling
Electric Force Space Charge
Density
Particle Charging
strong influence moderate influence weak influence
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
6
Physical ModelElectrostatics governing equations
∇2φ = −ρelε0
(1)
E∇ρel = −ρel
2
ε0(2)
φ electric potentialρel space charge densityε0 vacuum permittivityE electrical field
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
Test rig
COMSOLimplementation
2D Results
ValidationModel
Summary
7
Numerical ModelLaboratory test rig
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
Test rig
COMSOLimplementation
2D Results
ValidationModel
Summary
8
Numerical ModelCOMSOL implementation
units in m
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
Test rig
COMSOLimplementation
2D Results
ValidationModel
Summary
9
Numerical Model2D results - charge density distribution comparison
blue: ground / red: -20kV / orange: -5kV
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Geometry
Result
Validation
Summary
10
Validation Model2D axissymmetric geometry
❶ ❸ ❷ ❹
❺
50 mm
180 mm
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Geometry
Result
Validation
Summary
11
Validation ModelResults - comparison of space charge density [C/m3]
15 kV 20 kV 25 kV 30 kV
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Geometry
Result
Validation
Summary
12
Validation ModelComparison with test rig data
0
2
4
6
8
10
12
14
16
18
5 10 15 20 25 30 35
Ele
ctr
ic C
urr
en
t [µ
A]
Voltage on Electrode [kV]
Exp Ring 1
Exp Ring 2
Exp Ring 3
Exp Ring 4
Sim Ring 1
Sim Ring 2
Sim Ring 3
Sim Ring 4
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
13
Summary
Discussion
- 2D model → qualitatively appropiate- 3D model → not practicable- 2D axissymmetric model → trade-off
Achievements
- Model conceived, tested and applied- Successfully assist measurements and ongoing R&D
Conclusion & Outlook
- From test-case to industrially relevant model → demonstrates the power ofmultiphysics modelling for innovation purposes
- Further investigation and improvement guidance
Particle Control
DonatoRubinetti
Introduction
ParticleTrajectories
CoupledPhysics
PhysicalModel
NumericalModel
ValidationModel
Summary
14
Thank you for your attention!
Fruitful discussions with
- Beat Müller
- Trpimir Brzovic
- Daniel Jud
from OekoSolve AG are gratefully acknowledged. Further thanks to the SwissCommission for Technology and Innovation.
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
15
Modelling Objective
Physical understanding
• Deep understanding of the occurring effects• Spot relevant factors for optimization
Assisting empirical work
• Compare simulation results and experimental data• Guidance on measurement approaches
Predictive purposes
• Accelerate further R & D• Feasability and performance studies
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
16
AppendixCorona Onset Field Strength
E0 = 3× 106fr
(ms + 0.03
√msde2
)(3)
ms =p
pref
TrefT
(4)
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
17
AppendixParticle Charging Processes
Diffusion Charging
qd(t) =2πε0kTdp
eln
(1 +
t
τd
)(5)
Field Charging
qf (t) =
(3ε
ε+ 2
)πε0Edp
2 t
t+ τf(6)
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
18
Appendix2D/3D comparison - Electrical field strength magnitude
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
19
Appendix2D/3D comparison - Electrical field strength x-direction
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
20
Appendix2D/3D comparison - Electrical field strength y-direction
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
21
Appendix2D/3D comparison - Electrical field strength z-direction
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
22
AppendixMesh 3D
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
23
AppendixMesh 2D
Particle Control
DonatoRubinetti
Appendix
ModellingObjective
Corona OnsetField Strength
ChargingProcesses
2D/3D i
2D/3D ii
2D/3D iii
2D/3D iv
Mesh 3D
Mesh 2D
Mesh 2Dr
24
AppendixMesh 2D axisymmetric
IntroductionTechnologyPellet Burner
Particle TrajectoriesCoupled PhysicsPhysical ModelNumerical ModelTest rigCOMSOL implementation2D Results
Validation ModelGeometryResultValidation
Summary AppendixAppendixModelling ObjectiveCorona Onset Field StrengthCharging Processes2D/3D i2D/3D ii2D/3D iii2D/3D ivMesh 3DMesh 2DMesh 2Dr