eci - nanofluids: fundamentals and applications ii, august 15-20, 2010, montreal qed induced heat...

ECI - NANOFLUIDS: Fundamentals and Applications II, August 15-20, 2010, Montreal

QED Induced Heat Transfer

Thomas PrevenslikQED Radiations

Discovery Bay, Hong Kong

1


ThemeThe 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.

1a


Introduction

In 1822, Fourier published the transient heat conduction equation

2

where, C is the specific heat based on the concept of Lavoisier and Laplace in 1783

t

TCTK


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

3


Richard Feynman -1970Classical 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 4


Classical v. QM Heat Capacity

0.00001

0.0001

0.001

0.01

0.1

1 10 100 1000

Wavelength - - microns

Pla

nck

Ene

rgy

- E -

eV

1

kT

hcexp

hc

E

5

Nanoscale

kT 0.0258 eV

Classical

QM

By QM, absorbed EM energy at the nanoscale cannot be conserved by an increase in temperature. How conserved?


Conservation by QEDRecall 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.

6D2

For a spherical NP having diameter D, QED photons have

rn/c

f hfE

f = QED photon frequency E = Planck energy c = light speed nr = refractive index h = Planck’s constant


7

AbsorbQ

QEDQ

CondQ

T = 0

Instead, QQED is prompt non-thermal emission.

In < 5 fs, before phonons move, conservation gives

0 CondAbsorbQED QQQ

QQED is not Stefan-Boltzmann – no high temperatures

QED Induced Heat Transfer

dt

dNEQAbsorb

Replace Fourier Equation by:

E = Photon Planck Energy

dN/dt = Photon Rate

t

TCTK


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 FilmsQED emission negates reduced conductivity by phonons

ThermophonesSound by QED emission not film vibrations

NanofluidsExcluding QED emission leads to unphysical results 8


Molecular Dynamics

Akimov, et al. “Molecular Dynamics of Surface-Moving Thermally Driven Nanocars,”

J. Chem. Theory Comput. 4, 652 (2008). Discrete kT = 0, but kT > 0 assumed

Car distorts but does not moveMacroscopic 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, validMetropolis & Teller, 1950

9

For discrete nanostructures, MD of heat transfer is not valid. MD and DFT of the bulk under periodic boundary conditions are valid.


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.

10


QED Induced Redshift

RedshiftPhoton

o

NPGalaxyPhoton

o = 2nr D

11


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. 12


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

13

* 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.

Thin Films*


Reduced Conductivity

14

QED Heat Transfer QCond = QJoule - QQED ~ 0

Keff T = (QJoule- QQED) (df + dS ) / A T small, Keff ~ Bulk

No Reduced Conductivity

QQED

QCond

T

Current Approach QCond = QJoule

Keff T = Qcond (df + dS )/AT large, Keff small

Reduced Conductivity

QJoule

Film

Substrate

df

dSKf

KS


QED Emission

15

0

100

200

300

400

500

10 100 1000 10000

Film Thickeness - df - nm

The

rmal

Con

duct

ivity

- W

/ m

-K

.

0510152025303540

E(d

N/d

t) /

A (

T-T

o)

x10

9 W

/ m

2- K.

K - Keff Keff

QEDEmission

efff

QED KKd/TA

Q

QED emission negates reduced conductivity


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

16* T. Prevenslik, “Thermophones by Quantum Mechanics,”

ITHERM 2010, June 2-5, Las Vegas, 2010

Thermophones*


Classical Theory of Sound

Classical physics requires air vibration by diaphragm – wires?

Thin film (wires) theory by Arnold & Crandall in 1917.

0cdC;dt

dTaCTa2)t(sinRI p

22

C

f

r

RI

T2P

2

o

oorms

17


QM Theory of SoundIn 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?

QED Emission

AirMoleculesSound

Joule HeatI 2R sin2t

W

d

L

Wall No Sound

18


Nanofluids*

* 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.

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

19


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

20

DNA Damage by NPs

20a

Collision

DNA Damage

UV

H2OHydroxyl Radical

NP

Biological Cell Wall

NP

UV


Experiments show NPs cause DNA damage

mimics that by conventional ionizing radiation


Heated Surface 1300 K

NPs

QED

300 K

1300 K

* T. Prevenslik, “Boiling of nanofluids at a surface by quantum mechanics,” www.nanoqed.org at “Boiling Heat Transfer, 2010”

Pool Boiling*

21

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

http://www.nanoqed.org/


TankV

12x12x12 cm3

NPs

Bubbles

QT

Heater

QED

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.

Application*

22


PC Cooling*

* 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.

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

23


PC Cooling

24

Correct Literature for QED radiation losses not included in temperature changes of nanofluid

Heated PC Surface

NP

QED RadiationLossesTin

Tout


ConclusionsClassical 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 non-thermal 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.

25


Questions & Papers

Email: [email protected]

http://www.nanoqed.org

26

http://www.nanoqed.org/

eci - nanofluids: fundamentals and applications ii, august 15-20, 2010, montreal qed induced heat...

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