Transcript Presentation

QED Induced Heat Transfer
Thomas Prevenslik
QED Radiations
Discovery Bay, Hong Kong
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Theme
The controversy in Nanofluids over thermal conductivity and
heat transfer coefficient is only one in science.
Prominent scientists (Stokes, Rayleigh, Einstein, Hubble)
have been involved over the past century
Most of these controversies involve the nanoscale and find
origin the interpretation thereof by classical physics instead
of by quantum mechanics.
The theme of this presentation illustrates such controversies.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Introduction
In 1822, Fourier published the
transient heat conduction equation
  KT  C
T
t
where, C is the specific heat based on the concept of
Lavoisier and Laplace in 1783
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Classical Heat Transfer
Fourier Theory applicable to Macroscale
Heat capacity of a substance is assumed an
intensive property independent of quantity of
substance or size, but at nanoscale has a
problem with quantum mechanics - QM
Propose QED induced radiation as the heat
transfer mechanism at the nanoscale
QED = quantum electrodynamics
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Richard Feynman -1970
Classical physics by statistical mechanics allows the atom to have heat
capacity at the nanoscale.
QM also allows atoms to have heat capacity at the nanoscale, but only at
high temperature.
Submicron wavelengths that fit into nanostructures have heat capacity
only at temperatures > 6000 K
At 300 K, heat capacity is therefore “frozen out” at submicron wavelengths
Nothing New!
Paraphrasing Feynman 40 years later:
QM does not allow nanostructures at ambient temperature to conserve
absorbed EM energy by an increase in temperature
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Planck Energy - E - eV
Classical v. QM Heat Capacity
0.1
Classical
0.01
0.001
kT
0.0258 eV
hc

E
  hc  
exp  kT   1
 
 
QM
0.0001
0.00001
1
Nanoscale
10
100
1000
Wavelength - - microns
By QM, absorbed EM energy at the nanoscale cannot be
conserved by an increase in temperature. How conserved?
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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Conservation by QED
Recall from QM, QED photons of wavelength  are created by
supplying EM energy to a box having sides separated by  / 2.
Absorbed EM energy is conserved by creating QED photons
inside the nanostructure - by frequency up - conversion
to the resonance of the nanostructure.
c / nr
f

E  hf
f = QED photon frequency E = Planck energy
c = light speed nr = refractive index h = Planck’s constant
For a spherical NP having diameter D, QED photons have
  2D
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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QED Induced Heat Transfer
QQED is not Stefan-Boltzmann – no high temperatures
Q QED
Instead, QQED is prompt non-thermal emission.
In < 5 fs, before phonons move, conservation gives
QQED  Q Absorb  QCond  0
Q Absorb
T = 0
Replace Fourier Equation by:
  KT  C
Q Cond
T
t

Q Absorb  E
dN
dt
E = Photon Planck Energy
dN/dt = Photon Rate
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
QED Implications
Molecular Dynamics
Heat transfer simulations invalid for discrete nanostructures
Big Bang Theory
QED Redshift in cosmic dust means Universe is not expanding
Thin Films
QED emission negates reduced conductivity by phonons
Thermophones
Sound by QED emission not film vibrations
Nanofluids
Excluding QED emission leads to unphysical results
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Molecular Dynamics
Akimov, et al. “Molecular Dynamics of SurfaceMoving Thermally Driven Nanocars,”
J. Chem. Theory Comput. 4, 652 (2008).
Discrete  kT = 0, but kT > 0 assumed
Car distorts but does not move
Macroscopic analogy
Instead, QM forbids any increase in car
temperature. Hence, QED radiation is
produced that by the photoelectric
effect charges the cars that move by
electrostatic interaction with each other.
Sarkar et al., “Molecular dynamics
simulation of effective thermal
conductivity and study of enhance
thermal transport in nanofluids,”
J. Appl. Phys, 102, 074302 (2007).
Periodic Boundary Conditions
kT > 0, valid
Metropolis & Teller, 1950
For discrete nanostructures, MD of heat transfer is not valid.
MD and DFT of the bulk under periodic boundary conditions are valid.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Big Bang Theory
In 1929, Hubble measured the redshift of galaxy light
that based on the Doppler Effect showed the Universe is
expanding.
However, cosmic dust which is submicron NPs permeate
space and redshift galaxy light without Doppler effect.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
QED Induced Redshift
Galaxy
Photon

o = 2nr D
NP
Redshift
Photon
o
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Effect on Cosmology
The redshift: Z = (o - )/ > 0
occurs without the Universe expanding.
Astronomers will not find the dark energy to explain an
expanding Universe which is not expanding
Higgs boson unlikely to be found at LHC because
gravitational lensing measurement of dark matter is
negated by cosmic dust
Suggests a return to a static infinite Universe once
proposed by Einstein.
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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Thin Films*
Prompted by classical heat transfer being unable to explain the
reduced conductivity found in thin film experiments.
Moreover, explanations of reduced conductivity based on
revisions to Fourier theory by phonons are difficult to
understand and concluded by hand-waving
* T. Prevenslik, “Heat Transfer in Thin Films,” Third Int. Conf. on Quantum,
Nano and Micro Technologies, ICQNM 2009, February 1-6, Cancun, 2009.
Proceedings of MNHMT09 Micro/Nanoscale Heat and Mass Transfer
International Conference, December 18-21, 2009, Shanghai.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Reduced Conductivity
QJoule
Substrate
T
QQED
Film
Current Approach
QCond = QJoule
Keff T = Qcond (df + dS )/A
T large, Keff small
Reduced Conductivity
KS
QED Heat Transfer
QCond
Kf
dS
df
QCond = QJoule - QQED ~ 0
Keff T = (QJoule- QQED) (df + dS ) / A
T small, Keff ~ Bulk
No Reduced Conductivity
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
500
K - Keff
400
Keff
300
Q QED
200
AT / d f
 K  K eff
QED
Emissio n
100
0
10
100
1000

40
35
30
25
20
15
10
5
0
10000
E(dN/dt) / A (T-To) x10 9 W / m2K.
Thermal Conductivity - W / m -K.
QED Emission
Film Thickeness - df - nm
QED emission negates reduced conductivity
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Thermophones*
Over a century ago, Stokes communicated to the Royal
Society in 1880 the finding by Preece that electrical wires
produced sound.
In 1914, Rayleigh reported de Lange’s thermophone using
wires to the Royal Society
* T. Prevenslik, “Thermophones by Quantum Mechanics,”
ITHERM 2010, June 2-5, Las Vegas, 2010
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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Classical Theory of Sound
Classical physics requires air vibration by diaphragm – wires?
Thin film (wires) theory by Arnold & Crandall in 1917.
dT
I R sin (t )  2aT  aC ; C  dc p  0
dt
2
2
Prms
 o o I 2 R f


2 To r C
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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QM Theory of Sound
In 2008, Xiao et al. showed sound produced in CNT film, but no
vibration measured means classical theory not applicable.
Can sound be produced without film vibration?
Wall
No Sound
QED Emission
W
L
d
Sound
Air
Molecules
Joule Heat
I 2R sin2t
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Nanofluids*
Prompted by classical theory being unable to explain how
NPs increase thermal conductivity of common solvents
Moreover, tests showed enhancements in conductivity far
greater than given by standard mixing rules.
Heat Transfer (not Conductivity) enhanced
* T. Prevenslik, “Nanofluids by QED Induced Heat Transfer,”
IASME/WSEAS 6th Int. Conf. Heat Transfer, HTE-08, 20-22 August,
Rhodes, 2008,
“Nanofluids by Quantum Mechanics,” Micro/Nanoscale Heat and
Mass Transfer International Conference, December 18-21, Shanghai,
2009.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Heat Transfer Enhancement
Heat by collisions into NP in the FIR
(10 micron penetration)
NPs avoid Local Thermal Equilibrium
Heat out of NP beyond the UV
(1-10 centimeter penetration)
Penetration Ratio R = UV / FIR
R > 1  Heat is transferred over greater distance with
NPs than without NPs  Enhancement
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
DNA Damage by NPs
Experiments show NPs cause DNA damage
mimics that by conventional ionizing radiation
Biological
Cell Wall
NP
DNA
Damage
Collision
UV
UV
NP
H2O
Hydroxyl
Radical
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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Pool Boiling*
Paradox : High CHF without increased BHT coefficient
CHF – critical heat flux
BHT – boiling heat transfer
Explained by QED radiation from NPs bypassing boiling
surface and dissipating heat in the bulk
QED
NPs
300 K
1300 K
Heated Surface 1300 K
* T. Prevenslik, “Boiling of nanofluids at a surface by quantum
mechanics,” www.nanoqed.org at “Boiling Heat Transfer,
2010”
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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Application*
Bubbles
Tank
V
12x12x12 cm3
QED
NPs
Heater
QT
Too complex for analysis
Experiment using UV fluorescence with chemical markers
* You, et al., “Effect of nanoparticles on critical heat flux of
water in pool boiling heat transfer,” Appl. Phys Lett., 83,
3374, 2003.
ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
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PC Cooling*
Surprisingly, both papers strongly rebuked the long history
of nanofluids as enhanced coolants
Reports of small increases in HTC in channels and HTC
decreases in spray cooling compared to water alone but
both papers neglected QED radiation losses
HTC = heat transfer coefficient
* Schroeder,et al., “Nanofluids in a Forced-Convection Liquid Cooling
System – Benefits and Design Challenges,“ ITHERM 2010, June 2-5,
Las Vegas, 2010.
Bellerova et al., “Spray Cooling by Al2O3 and TiO2 Nanoparticles in
Water,” ITHERM 2010, June 2-5, Las Vegas, 2010.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
PC Cooling
QED
Radiation
Losses
Tin
Tout
NP
Heated PC Surface
Correct Literature for QED radiation losses not included in
temperature changes of nanofluid
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Conclusions
Classical heat transfer based on statistical mechanics at the nanoscale
is negated by QM because the heat capacity of the atom vanishes
QED heat transfer conserves absorbed EM energy by prompt nonthermal QED radiation negates conductive heat flow by phonons
Phonon derivations of reduced thermal conductivity are meaningless
because conduction does not occur.
Heat capacity is an extensive property depending
on size and amount of substance
MD heat transfer simulations of discrete nanostructures are invalid,
but DFT of the bulk and dynamics of discrete QED charged
nanostructures are valid.
Transient Fourier heat flow may be replaced by the a priori assumption
that absorbed EM energy is emitted by QED at the frequencies of
the EM resonances of the nanostructure – go from there.
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal
Questions & Papers
Email: [email protected]
http://www.nanoqed.org
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ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal