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Nanoscale Heat Transfer in Thin Films Thomas Prevenslik Discovery Bay, Hong Kong, China 1 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21,

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Presentation on theme: "Nanoscale Heat Transfer in Thin Films Thomas Prevenslik Discovery Bay, Hong Kong, China 1 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21,"— Presentation transcript:

1 Nanoscale Heat Transfer in Thin Films Thomas Prevenslik Discovery Bay, Hong Kong, China 1 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

2 Background Over the past 30 years, heat transfer in thin films has been based on classical methods. However, for films less than about 100 nm, classical heat transfer cannot explain the reduced thermal conductivity found in experiments. T. Prevenslik, “Heat Transfer in Thin Films,” Third Int. Conf. on Quantum, Nano and Micro Technologies, ICQNM 2009, February 1-6, Cancun, 2009. ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China 2

3 Experimental Data Bulk Copper 3 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

4 Experiment 4 Pulse Method (Thin Solid Films, Kelemen, 36 (1976) 199-203) Thermal Diffusivity K = thermal conductivity  = density, c = specific heat X1X1 X2X2 T1T1 T2T2 Wire FF Data Shows K  0 as  f  0 Substrate Film Problem Diffusivity  diverges as c  0 Instability requires testing with the film combined with substrate. Davitadze, et al., App. Phys. Lett.. 89 (,2002) SS W ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China L

5 Current Approach To explain reduced conductivity data, Fourier heat conduction theory is thought not applicable to thin films having thickness < than the mean free paths of phonons. Heat Transfer in thin films is modified to treat phonons as particles in the Boltzmann Transport Equation (BTE). 5 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

6 Purpose 6 To provide a QM explanation for thin film heat transfer based on QED induced EM radiation QM = Quantum Mechanics QED = Quantum Electro Dynamics EM = Electromagnetic ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

7 QED induced EM radiation Classically, heat is conserved by an increase in temperature. But at the nanoscale, QM forbids heat to be conserved by an increase in temperature because specific heat vanishes. QED allows heat to be conserved by the frequency up- conversion of kT energy to the EM confinement frequency of the film which escapes by the emission of nonthermal EM radiation 7 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

8 Thin Film 8 QED Heat Transfer Q Cond = Q Joule - Q QED  T 2 = (Q Joule - Q QED ) (  f +  S ) / A K eff Q QED / Q Joule =  T 1 /  T 2 -1 Q QED Q Cond TT Current Approach Q Cond =Q Joule  T 1 = Q Joule (  f +  S ) / A K eff Q Joule ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China Effective Conductivity K eff = [K f /  f + K S /  S ] / (  f +  S )

9 EM Confinement For  << W and L,  2  n r Photons in Rectangular cavity resonator, n r > 1 9 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China kT 3 DOF confined 3 DOF 1 DOF confined

10 QM Restrictions 10 Film 0.0285 eV ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

11 Thin Film Specific Heat 3 microns ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China 11

12 QED radiation in NPs Specific Heat Vanishes No Temperature change EM Emission = 2Dn r Molecular Collisions Nanofluids Room B, 2 PM Laser/Solar/Supernovae Photons Residual kT Energy Tribochemistry Joule Heat NP 12 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

13 QED Induced Heat Transfer 13 Non Thermal Emission E P = Photon Planck Energy dN P /dt = Photon Rate ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

14 QED induced Heat Transfer 14 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

15 Conclusions Thin film specific heat vanishes. Film temperatures follow the substrate. PWR fuel rod cladding simulated in ANSYS by coupling clad temperatures with substrate. No need to modify bulk conductivity for thin films Heat loss normal to the surface by QED emission. QED emission can and should be measured with standard photomultipliers for 100 nm films. 15 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

16 Extensions Einstein’s Static Universe Redshift in cosmic dust means Universe is not expanding and dark energy does not exist. Tribochemistry Rubbing of surfaces produces NPs that produce VUV to enhance chemical reactions Gecko walking on walls and ceilings Spatulae under on hair tips act as NPs to produce electrostatic attraction Unification of Static Electricity Rubbing of surfaces produces NPs that charge the surroundings. Nanocatalysts and Chemiluminescence Gold NPs added to chemical reactants in solution enhance chemical reactions X-rays from peeling Scotch Tape NPs that form as adhesive tears accumulates charge that at breakdown produces x-rays Casimir force BB thermal radiation in gap between parallel plates produces attraction Etc… 16 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China

17 Questions & Papers Email: thomas@nanoqed.net http:// www.nanoqed.org 17 ASME Micro/Nanoscale Heat / Mass Transfer Int. Conf., Dec. 18-21, 2009 — Shanghai, China


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