reza baghaei lakeh ph.d. candidaterbaghae/proposal.pdf · conclusion. corona wind and ion-drag...
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ENHANCEMENT OF CONVECTIVE HEATTRANSFER IN INTERNAL FLOWS USING ANELECTRICALLY-INDUCED CORONA JET
Reza Baghaei LakehPh.D. Candidate
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
CORONA DISCHARGE
Ionization of a neutral gas surrounding a conductor Strong electric field near a sharp electrode Ionization of neutral molecules
CORONA DISCHARGE
Ion generation mechanisms: α – process (electron impact ionization)α process (electron impact ionization)
γ – process (electron emission from cathode)
Field Emission (Electron Quantum Tunneling ) Field Emission (Electron Quantum Tunneling )
Electrons in a metal see a Electrons in a metal see a surface potential barrier due to the material’s work function.
For strong enough electric fields, the electrons can tunnel through the barrier tunnel through the barrier and materialize in the gap space.
Gomer, “Field Emission and Field Ionization,” 1961
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
CORONA WIND AND ION-DRAG FLOWS
Engineering point of view neglect “Sheath Layer”!I j ti f th i (O + d N + ) Injection of the ions (O2
+ and N2+ )
Dragging the neutral molecules and imposing a bulk flow referred as “Corona Wind” or “Ion-Drag” flow
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
APPLICATIONS
Ion-Drag pumps
Heat Transfer Electrostatic Adamiak, 2004
Garimella, 2009
Transfer Enhancement
EHD Drag
R d i
Precipitators
EHD Thrusters
Reduction
Cooling
Lerner, 2000Go, 2010
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
BRIEF LITERATURE REVIEW
Pioneers: Velkoff (1963) and Moss (1966)
• Experimental Experimental • Circular Tube• Influence of Electric Field on the flow field and heat
transfer• Suggested Flow Field based on Heat Transfer
Augmentation:Augmentation:
S.M. Macro, H.R. Velkoff, Effect of Electrostatic, ASME Paper No. 63-HT-9, 1963R.A. Moss, J. Grey , Proceeding of Heat Transfer and Fluid Mechanics Institute, Santa Clara, CA , 1966
BRIEF LITERATURE REVIEW
Ohadi and Nelson (1987)
• Experimental • Circular tube• Noticeable heat transfer enhancement• Noticeable pressure dropNoticeable pressure drop
M.M. Ohadi, D.A. Nelson, S. Zia, International Journal of Heat and Mass Transfer, 1987
BRIEF LITERATURE REVIEW
Seyed-Yagoobi and Owsenek
• Experimental Numerical• Experimental, Numerical• EHD flow by electric conduction• Dielectric liquid refrigerants (Dissociation & Dielectric liquid refrigerants (Dissociation &
Recombination)• Heat Transfer enhancement in channels and ducts
B.L. Owsenek, J. Seyed-Yagoobi,, Journal of Heat Transfer, 1997
BRIEF LITERATURE REVIEW
Garimella (Cooling Technology Research Center)
• Experimental Numerical• Experimental, Numerical• Ion- Drag flows in micro-scale• Low voltage ionization (Quantum Tunneling)Low voltage ionization (Quantum Tunneling)• Enhancement of heat transfer in internal and external
flows
D.B. Go, S.V. Garimella, T.S. Fisher, IEEE 10th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronics Systems, 2005
BRIEF LITERATURE REVIEW
Lai et al
• Experimental NumericalExperimental, Numerical• EHD gas pumps using needle-to-ring electrodes• Noticeable delivery of airflow y• Developed the EHD Drying mechanisms• Oscillatory flows
F.C. Lai, J. Mathew, Journal of Heat Transfer, 2007
BRIEF LITERATURE REVIEW
Molki et al.
• Experimental Numerical • Experimental, Numerical • Electrically-induced Secondary flow fields • Effect of corona discharge on natural convectionEffect of corona discharge on natural convection• Heat Transfer enhancement in channels with
rectangular, triangular and circular cross sections
M. Molki, K.L. Bhamidipati, International Journal of Heat and Mass Transfer, 2004
BRIEF LITERATURE REVIEW
Go and Balagopal (2011)
• ExperimentalExperimental• Localized Hot Spot Cooling• Wire-to-Rod• Counter-flow ionic wind and impingement-like effect• Cooling as much as 5K
Go and Balagopal, ESA Annual Meeting on Electrostatics, 2011
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
ION-DRAG FLOW IN CIRCULAR TUBES
Wire – tube Radial body force Navier – Stokes
ρEρuν
ρPu.u
tu c2
General view:
Wangnipparnto et al., Journal of Energy Conversion and Management, 2003
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
FORMULATION OF THE PROBLEM
Maxwell Equations in Electrohydrodynamics reduce to
Gauss’s Law
Maxwell–Faraday equation
Continuity Continuity
Magnetic field equations (rarely needed in Electrohydrodynamics)
FORMULATION OF THE PROBLEM
Electric Potential
Gauss’s Law
Conservation of electric charge
Ion mobility is the Electric current density Ion mobility is the dominant term of current density
y
Charge Convection Electric Conduction
Charge Diffusion
FORMULATION OF THE PROBLEM
B d C di i Boundary Conditions Electric Potential (Elliptic PDE)
V = Vo @ emitting electrode (Wire) V = 0 @ collecting electrode (Tube)
Charge Density (Hyperbolic PDE)Charge Density (Hyperbolic PDE) ρ = ρc,o @ emitting electrode ρc,o is found by measuring the time-average corona current
experimentally.p y
M. Molki, K.L. Bhamidipati, International Journal of Heat and Mass Transfer, 2004
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
ELECTRIC FIELD RESULTS+
Method of characteristics ++
Fluctuations i FVM in FVM Solution
Method of Characteristic Finite Volume Method
Baghaei Lakeh, R., Molki, M., ASME International Mechanical Engineering Congress & Exposition, 2009
FLOW FIELD RESULTS
Concentric configuration Hydrostatic condition Eccentric configuration
Secondary Flow Fi ldField
Recirculation Zones
Corona Jet
Baghaei Lakeh, R., Molki, M., Journal of Fluids Engineering, 2010
HEAT TRANSFER ENHANCEMENT
The corona-induced jet flow can significantly enhance the local heat transfer.
Hot Components
Temperature distributionMolki, M., Baghaei Lakeh, R., 63rd Annual Meeting of the American Physical Society, Division of Fluid Dynamics, 2010
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
PROPOSED RESEARCH
Ion-Drag flows in channels
Generating pumping effectHeat Transfer Enhancement
Disturbing the Boundary Layer Parallel Electric Force
Secondary Flows Fields
Direction of electric body-force in parallel configurationg
Corona Jet
PROPOSED RESEARCH
Corona Jet Circular Tube (eccentric wire
electrode)electrode)
Rectangular Channel with Rectangular Channel with longitudinal flat electrodes
PROPOSED RESEARCH
Methodology•Analytical (Method of Characteristics)•Computational (Finite Volume Method)
Electric Field
•Computational (Finite Volume Method)•Programming the code in C++•Experimental (Measurement of time-averaged corona current)
Flow ld
•Interpolating electric body-force between Electric Field and Flow Field grid points
•User-Defined-Function (UDF)•Commercial CFD Software ANSYS FLUENT 13Field •Commercial CFD Software, ANSYS FLUENT 13
Heat Transfer
•Temperature field•Heat Transfer Enhancement
PROPOSED RESEARCH
Extensive Grid Refinement Study according to Fluids Engineering Division of ASME.*g g
VerificationAnd
ValidationValidation
Comparison with i lifi d A l ti l
Comparison with il bl E i t l simplified Analytical
solutionsavailable Experimental
literature.
* Celik, I.B., Journal of Fluids Engineering, 2010
* Roache, P.J., Proceedings of Quantification of Uncertainty in Computational Fluid Dynamics, 1997
PROPOSED RESEARCH
Expected Results• Distributions of Electric field and Charge density :C g y
• Circular channels with centered wire electrode
• Rectangular channels with parallel longitudinal electrode arrays.y
• Secondary flow field on the cross section of the channels or along the channel axischannels or along the channel axis
• The effect of electric body-force on the buoyancy y y ydriven flows
PROPOSED RESEARCH
E t d R ltExpected Results•Distribution of temperature fields in various
configurations in rectangular and circular channels.
•The enhancement level of convective heat transfer using electrically-driven secondary flow fields in fully developed and developing regions of channels.
•Developing the targeted-cooling method by corona jets in circular and rectangular
igeometries.
PRESENTATION OUTLINEPRESENTATION OUTLINE
Corona Discharge Corona Wind and Ion-Drag Flows Applications
B i f Lit t R i Brief Literature Review Ion-Drag flow in Circular Tubes Formulation of the Problem Formulation of the Problem Preliminary Results Proposed Researchp Conclusion
CONCLUSION
Corona Discharge may lead to formation of Ion-Drag flows or Corona Discharge may lead to formation of Ion Drag flows or corona wind.
The electrically-induced secondary flow fields can be used for many applications including Heat Transfer Enhancement.
The ion-drag flows in some configurations lead to formation of a corona jet which may be used in different applications.
The proposed research studies the enhancement of heat transfer in internal flows and develops the idea of targeted spot cooling using a corona jet.p g g j