1. ME381R Lecture 1 Overview of Microscale Thermal Fluid Sciences and Applications Dr. Li Shi Department of Mechanical Engineering The University of Texas at Austin Austin, TX 78712 www.me.utexas.edu/~lishi lishi@mail.utexas.edu

2. 2 Microprocessor Evolution

3. 3 Steve Kang et al. Electrothermal analysis of VLSI Systems, Kluwer 2000 Localized Heating in VLSI Chips  T=20C Mean-time-to-failure due to electromigration increase x5 110C 108C 90C 80C 1 cm On chip temperature contour Dependence of mean time between failure on temperature

4. 4 Telecommunication Data Rate Evolution 1.44MB Floppy Disk 1.00 GB Hard Drive Howard Banks, "Life at 100 billion bits per second", Forbes Magazine, Oct. 6, 1997

5. 5 A. Shakouri, J. Christofferson, Z. Bian, and P. Kozodoy, “High Spatial Resolution Thermal Imaging of Multiple Section Semiconductor Lasers,” Proceeding of Photonic Devices and System Packaging Symposium (PhoPack 2002), pp22-25, July 2002, Stanford CA. Thermal Issues in Optoelectronic Integrated Circuits Affolter, WDM Solutions (supplement to Laser Focus World), P.65 June 2001, www.wdm-solutions.com

6. 6 IC Thermal Management Challenge Courtesy: Prof. Ken Goodson, DARAPA Thermal Management Workshop

7. 7 Electroosmotic Microchannel Cooling System

8. 8 Cooligy 150 W PC Prototype

9. 9 Thermoelectric Refrigeration Electronics Optoelectronics Automobile Consumer Marlow Single-Stage Thermoelectric cooler No moving parts: quiet No CFC: clean Low efficiency

10. 10 Efficient Thin Film Thermoelectric Coolers Venkatasubramanian et al, Nature 413, P. 597 (2001) Thin film superlattice

11. 11 McMasters & Cummings, Journal of Aircraft, Jan-Feb 2002 Airplane Speed- Past, Present, Future How far exponential growth in electronics and fiber optics can continue? The brick wall due to heating, fabrication cost, quantum mechanics … Future challenges & opportunities: transportation, communication, energy, health care …

12. 12 Electric power generator with no moving part Power sources for NASA space probe NAVY Electric Ships (Seapower 21) Waste heat recovery (cars, power plants, …) Microscale power sources Direct Thermal to Electric Energy Conversion Spacecraft Power Source Efficient Nanostructured Thermoelectric Power Generator

13. 13 Microfluidic Chip for Continuous Glucose Monitoring (J. Zahn et al.)

14. 14 Length Scale 1 m 1 mm 1  m 1 nm Human Automobile Butterfly 1 km Aircraft Computer Wavelength of Visible Light MEMS Width of DNA Microprocessor, NEMS Blood Cells Microprocessor Module Nanotubes, Nanowires Particle transport theories, molecular dynamics… 100 nm Fourier’s law, Novier-Stokes l

15. 15 Thermal conductivity Hot T h Cold T c L Q (heat flow) Fourier’s Law for Heat Conduction

16. 16 Microscopic Origins of Thermal Fluid Transport --The Particle Nature Materials Dominant energy carriers Gases: Molecules Metals: Electrons Insulators: Phonons (crystal vibration) In micro-nano scale thermal fluid systems, often L < mean free path of collision of energy carriers & Fourier’s law breaks down  Particle transport theories or molecular dynamics methods L Hot Cold