effect of magnetic fields on fire katsuo maxted aviation fire dynamics march 15, 2013
TRANSCRIPT
Effect of Magnetic Fields on Fire
Katsuo MaxtedAviation Fire Dynamics
March 15, 2013
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Modeling Affects on a Diffusion Flame• Benefits Using Magnetism
IntroductionMagnetism
• Defined as the phenomena that accounts to forces exerted by magnets
• Depends on other magnetic fields, temperature, and pressure
Introduction
N S
Types of Magnets
• Ferromagnets are permanent and have the strongest influence.
Introduction
N S
Types of Magnets
• Paramagnets are temporary magnets that created from an applied magnetic field
N S
IntroductionTypes of Magnets• Diamagnets are the weakest
magnets that exhibit an opposing magnetic field to an applied one
N S
S N
IntroductionTypes of Magnets
• Electromagnets are magnets composed of wires carrying an electric current
N S
Introduction
• Bio-magnetics [1]
• Magnetic Resonance Imaging (MRI)
• Enhance Combustion Processes
Magnetic Fields have been applied in:
Introduction• Units are in T (Tesla) for
strength and T/m (Tesla per meter) for intensity
• Refer to magnetic gradient for multiple field lines
• Paramagnetism, Ferromagnetism, & Diamagnetism
Introduction
• Oxygen is known for its paramagnetism
• Nitrogen, Carbon Dioxide, and most hydrocarbon fuels are repelled because of their diamagnetic nature [2, 3]
Magnetic field affects all gases:
http://www.youtube.com/embed/ozhIQG8XBkY
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Modeling Affects on a Diffusion Flame• Benefits Using Magnetism
Magnetic Properties• In the presence of an external
magnetic field, a flame on wax paper forms an equatorial disk and is more luminous
• Faraday attributed this to deflection of charged particles from the flame
• Von Engel & Cozens said deflection is caused by diamagnetic gases
Background [4, 5, 6]
Magnetic Properties• For highly conductive fluids like
plasma and salt water, Lenz’s law indicates that a charged fluid will follow the direction of a magnetically induced electromotive force
• Magnetic field lines perpendicular to fluid flow direction increase it’s speed while parallel magnetic fields do the opposite [2]
Effect on Fluid Flow
Magnetic PropertiesEffects in Chemical Reactions
• Spin (S) indicates the angular momentum of a charged particle
• The multiplicity or overall spin of a molecule is defined as 2S + 1 where S = ½*(number of unpaired electrons)
• Maxwell’s theory states that a moving charged particle creates a magnetic moment, indicating that a higher spin generates a stronger magnetic moment
Magnetic PropertiesEffects in Chemical Reactions [7]
• Oxygen gas (which is in a singlet state) must be broken into triplets before becoming paramagnetic
• Radicals are paramagnetic with a spin S = ½
• Diamagnetic effects cause radicals to form in pairs, causing doublets to excite to triplets, and after reaction, spins are conserved from diamagnetic predecessors
Magnetic PropertiesEffects in Chemical Reactions [7]
• Magnetic control on spin
• Four spin states: exchange interaction, electron spin-dipolar interaction, hyperfine interaction and Zeeman interaction
Magnetic PropertiesEffects in Chemical Reactions• Example: Photochemical
Process [8]
Stationary temperature dependence of the reacting system on external radiation value in the presence and in the absence of magnetic field
Magnetic PropertiesEffects in Chemical Reactions• Example: Photochemical
Process [8]
Stationary concentration dependence of biradicals on external radiation value in the presence and in the absence of magnetic field
Magnetic Properties• Magnetic field Intensity of 1 T is
said to alter combustion characteristics [3, 9]
• Production of 1 T rare-earth magnets can replace the need for electromagnets [10, 11]
Magnetic Properties
• Oxygen has randomly oriented dipole moments that align with the applied field
• Nitrogen, Carbon Dioxide and most hydrocarbon fuels form a net dipole moment in opposition to the applied field
Dipole alignment
Magnetic Properties• First Regime - At low velocities, gas
flow is diffused through the magnetic curtain.
• Second Regime - At slightly higher flow velocities, gas flow is blocked at the highest magnetic field gradient
• Third Regime - At higher flow rates, the gas flow is allowed to pass though curtain in a pinched fashion
Three Regimes for blocking gas flow [12]:
Magnetic fields do not separate nitrogen and oxygen!
Magnetic Properties• Application of magnetic field
gradients of 20-200T/m under 0.5 - 1.4 T decreased combustion temperature from 200 to 100 ˚C
• Combustion rate decreased for location of highest magnetic field strength
• Candle flame, hydrogen flame and methane flame are also deflected toward lesser magnetic field strengths
For combustion of alchohol [1, 2]
Magnetic Properties• Candle flame can be quenched
between two cylindrical electromagnets when interacting with a field strength of 1.5 T and intensity gradient of 50-300 T/m in a 5-10 mm space
• Flame is not quenched below 0.9 T
Flame Quenching [3]
Magnetic Properties
• Magnetic field near reaction zone greatly increases emission intensity
• Cleaner burning - soot levels are decreased
Radiative Emissions from Diffusion Flames [13]
Magnetic Properties
• Larger influence on diffusion flames due to buoyancy induced convective air flow
• Longer burning periods on diffusion flames
• Affects flame shape without pressurized containments
Studies in Microgravity [14, 15, 16]
Magnetic Properties
• In microgravity, the magnetic field causes the flame to behave like it’s subjected to buoyant forces (which can be isolated in normal gravity)
• Large soot particles can be decreased
Studies in Microgravity [14, 15, 16]
Magnetic Properties• Uniform Magnetic field produces no
observable change
• Combustion is enhanced in the presence of a decreasing magnetic field
• Ferromagnets are ideal for experimentation due to the absence of Ampere and Lorenz forces
Summary
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Modeling Affects on a Diffusion Flame• Benefits Using Magnetism
Magnetic Confinement FusionPlasma in Relation to Fire• Plasma is defined as a quasineutral gas composed of charged and neutral particles
• The ‘reaction zone’ of a diffusion flame at high pressure may be characterized as a plasma
http://www.youtube.com/embed/uPU9cEK5YsM
Magnetic Confinement Fusion
• Stellarator
• Toroidal Tokamak
• Spherical Tokamak
Magnetic Confinement Fusion• Stellarator [17]
QPS Coil-sets and plasma. Modular coils are shown in light blue, toroidal field coils are pink, vertical field coils are in tan. Color contours (blue = low field, red = high field) show the magnetic field strength on the outer plasma magnetic flux surface
Magnetic Confinement Fusion• Toroidal Tokamak [18]
33
Magnetic Confinement Fusion• Spherical Tokamak [19]
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Modeling Affects on a Diffusion Flame• Benefits Using Magnetism
Plasma Torch[20]• Hybrid (RF + DC) plasma
torch
Plasma Torch[20]• Direct Current Induction
Includes anodes, cathode and gas inlets
Plasma Torch[20]
• Radio-frequency Induction
Advantages: large volume plasma generation; cleanness; simplicity; easy in-feeding into plasma; long lifecycle
Includes metal water-cooling sections; quarts tube; body corpus and gas former
Plasma Torch[20]
Plasma Torch[20]
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Modeling Affects on a Diffusion Flame• Benefits Using Magnetism
Affects on Diffusion Flame [21]
Affects on Diffusion Flame [21]
Evolution of the temperature along the flame axis, lift-off height and flame length with the injection velocity of air in the presence of a magnetic field(MF) and without magnetic field(WMF) for two injection velocities of CH4: 0.54(a) and 0.79(d) for a position of the burner Z = +85mm.
Affects on Diffusion Flame [21]
Evolution of the visual lift-off height with the injection velocity of air in the presence of a magnetic field (MF) and without magnetic field (WMF) for two injection velocities of CH4: 0.54 and 0.79 m/s for a position of the burner Z = -185mm.
Affects on Diffusion Flame [21]
Affects on Diffusion Flame [21]
• Analysis
• Magnetic fields of decreasing strength lengthen lift-off height and accelerate normal convection
• Thermo-magnetic convection slows normal convection for fields of increasing strength
Field ModelingSolenoid (hollow)
Diffusion Flame
Magnetic Field Lines
Field Modeling•Geometry
0
Coil
Field Modeling•Biot-Savart Law
Field Modeling•Biot-Savart Law
Field Modeling•Biot-Savart Law
Field Modeling• Biot-Savart Law
• Magnetic field vector in 3D space is determined by the addition of two integrals for two coils.
• Ends of solenoids are connected with a sinusoidal function
• The connectors distort magnetic fields lines so data was taken away from the connectors
Field Modeling
Observations• Magnetic fields lines running
through the outer regions of the electromagnets are unpredictable and highly sensitive to initial conditions
• Field lines not affected by chaos slightly deviate from their initial linear paths when between magnets
Conclusions• More coil windings (and hence a
stronger magnetic field) give straighter magnetic field lines between the two solenoids, giving the flame an increased linear stability
• A longer flame length is due to the stronger influence from the central area of an electromagnet
• Flame behavior in outer regions of electromagnets is unpredictable
Outline• Introduction• Magnetic Properties in Combustion• Magnetic Confinement Fusion• Magnetic Induction in a Plasma Torch• Magnetic Field Line Modeling• Benefits Using Magnetism
Fire Suppression• Fire scan be suppressed through
electromagnetic pulses, which is an environmentally friendly alternative for water and chemicals
• Pulses are meant to scatter gases necessary for reactions to take place.
• Not applicable to large scale fires!
Applications• Useful for entraining oxygen in
microgravity environments
• Flame stabilization in combustion engines
• Experimental research in plasma assisted combustion
References
[1] S. Ueno and K. Harada, “Experimental Difficulties in Observing the Effects of Magnetic Fields on Biological and Chemical Processes”, IEEE Transactions on Magnetics, Vol. MAG-22, No.5, September 1986, pp. 868-873.
[2] S. Ueno and K. Harada, “Effects of Magnetic Fields on Flames and Gas Flow”, IEEE Transactions on Magnetics, Vol. MAG-23, No.5, September 1987, pp.2752-2754.
[3] S. Ueno, “Quenching of Flames by Magnetic Fields”, Journal of Applied Physics, Vol. 65, No. 3, February 1989, pp. 1243-1245.
[4] Prof. Zantedeschi, “ On the Motions Presented by Flame when under the Electro-Magnetic Influence”, The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, Series 3, Vol. 31, No. 210, December 1847, pp.401-424.
[5] M. Faraday, “ On the Diamagnetic Conditions of Flame and Gases”, The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, Series 3, Vol. 31, No. 210, December 1847, pp.401-421.
[6] A. V. Engle and J. R. Cozens, “Flame Plasmas,” Advances in Electronics and Electron Physics, Vol. 20, 1964, pp. 99-146.
[7] U. E. Steiner, “Spin Chemistry: how magnetic fields affect chemical reactions”, Summer School on Magnetic Fields in Science, University of Konstanz, Cargese, Corsica, 2007. Received from http://mfs-cargese.grenoble.cnrs.fr/Steiner_Abstract.pdf.
References
[8] A. A. Kipriyanov (Jr.), P. A. Purtov, “Magnetic field effects on chemical reactions near the disturbance of stationary states conditions”, Chaotic Modeling and Simulation (CMSIM) 1: 53-65, 2012
[9] T. Aoki, “Radicals’ Emissions and Butane Diffusion Flames Exposed to Upward Decreasing Magnetic Fields,” Japanese Journal of Applied Physics, Vol. 28, 1989, pp. 776-785.
[10] J. Baker, M. E. Calvert, K. Saito and R. Vander Wal, “Holographic Interferometry and Laminar Jet Diffusion Flames in the Presence of Non-Uniform Magnetic Fields”, Sixth International Microgravity Conference, 2001, pp. 361-364.
[11] J. Baker, M.E. Calvert, K. Saito and R. Vander Wal, “An Analytical Model for Non-Uniform Magnetic Field Effects on Two-Dimensional Laminar Jet Diffusion Flames”, Sixth International Microgravity Conference, 2001, pp. 361-364.
[12] S. Ueno and M. Iwasaka, “Properties of Magnetic Curtain Produced by Magnetic fields”, Journal of Applied Physics, Vol. 67, No. 9, May 1990, pp. 5901-5903.
[13] N. I. Wakayama, “Effect of a Gradient Magnetic Field on the Combustion of Methane in Air”, Chemical Physics Letters, Vol. 188, No. 3, Jan. 1992, pp. 279-281.
[14] N. I. Wakayama, “Magnetic Support of Combustion in Diffusion Flames under Microgravity”, Combustion and Flame, Vol. 107, 1996, pp. 187-192.
References
[15] N. I. Wakayama, “Utilization of Magnetic Force in Space Experiments”, Advances in Space Research, Vol. 24, No. 10, 1999, pp. 1337-1340.
[16] F. Khaldi, K. Messadek, A. M. Benselama, “Isolation of Gravity Effects on Diffusion Flames by Magnetic Field”, Microgravity Sci. Technology (2010) 22:1-5.
[17] D. A. Spong, D. J. Strickler, S. P. Hirshman, J. F. Lyon, L. A. Berry, D. Mikkelsen, D. Monticello, A. S. Ware, “confinement physics and flow damping in quasi-poloidal stellarators”, The 14th International Stellarator Workshop, Griefswald, Germany, 2003.
[18] Picture received from http://www.plasma.inpe.br/LAP_Portal/LAP_Site/Text/Tokamaks.htm.
[19] World Nuclear Association, Ian Hore-Lacy (Lead Author);PPPL (Content Source);Cutler J. Cleveland (Topic Editor) "Nuclear fusion power". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth December 6, 2009; Last revised Date December 6, 2009; Retrieved March 14, 2013 <http://www.eoearth.org/article/Nuclear_fusion_power>
[20] V. Frolov, I. Matveev, D. Ivanov, S. Zverev, B. Ushin, G. Petrov, “experimental investigations of the hybrid plasma torch with reverse vortex stabilization “, Applied Plasma Technologies, 1729 Court Petit, McLean, VA 22101, USA. Received from http://www.nipne.ro/rjp/2011_56_Suppl/0036_0040.pdf.
[21] M. Chahine, P. Gillon, B. Sarh, J. N. Blanchard, V. Gilard, “Magnetic Field Effect on Methane/Air Diffusion Flame Characteristics”, Universite d’Orleans, 16 Rue d’Issoudun – BP 16729 45067 Orleans cedex 2, France. Received from http://data.cas.manchester.ac.uk/database3/SAMPLE%20III/Dropbox%20stuff/ECM/ECM%202011%20Papers/320.pdf.
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