ME381R Lecture 1

Overview of Microscale Thermal Fluid Sciences and Applications

Dr. Li ShiDepartment of Mechanical Engineering

The University of Texas at AustinAustin, TX 78712

www.me.utexas.edu/~lishi lishi@mail.utexas.edu

2

Microprocessor Evolution

Source: IntelSource: Intel

1,000,0001,000,000

100,000100,000

10,00010,000

1,0001,000

1010

100100

11

1 Billion 1 Billion TransistorsTransistors

80868086

8028680286i386i386

i486i486PentiumPentium®®

KK

PentiumPentium®® IIII

’’7575 ’’8080 ’’8585 ’’9090 ’’9595 ’’0000 ’’0505 ’’1010

PentiumPentium®® IIIIIIPentiumPentium®® 44

’’1515

Source: IntelSource: Intel

1,000,0001,000,000

100,000100,000

10,00010,000

1,0001,000

1010

100100

11

1 Billion 1 Billion TransistorsTransistors

80868086

8028680286i386i386

i486i486PentiumPentium®®

KK

PentiumPentium®® IIII

’’7575 ’’8080 ’’8585 ’’9090 ’’9595 ’’0000 ’’0505 ’’1010

PentiumPentium®® IIIIIIPentiumPentium®® 44

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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

108C90C80C

1 cm

On chip temperature contour

Dependence of mean time between failure on temperature

4

Telecommunication Data Rate Evolution

1

103

106

109

1012

1800 1850 1900 1950 2000 2050

Year

Data Rate (bits/sec)

Doubles every4.7 years

Telephone

Transcontinental cable

Coaxial circuits

Fiber

WDMDWDM

Telegraph

Doubles every 16 months

1.44MB Floppy Disk

1.00 GB Hard Drive

Howard Banks, "Life at 100 billion bits per second", Forbes Magazine, Oct. 6, 1997

5

Electroabsorption modulator

Waveguide Ridge

20um

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

IC Thermal Management Challenge

Courtesy: Prof. Ken Goodson, DARAPA Thermal Management Workshop

7

Electroosmotic Microchannel Cooling System

8

Cooligy 150 W PC Prototype

9

Thermoelectric Refrigeration

• Electronics • Optoelectronics

• Automobile

• Consumer

• Marlow Single-Stage Thermoelectric cooler

• No moving parts: quiet

• No CFC: clean

• Low efficiency

10

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

Thin film superlattice

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?

Source: IntelSource: Intel

1,000,0001,000,000

100,000100,000

10,00010,000

1,0001,000

1010

100100

11

1 Billion 1 Billion TransistorsTransistors

80868086

8028680286i386i386

i486i486PentiumPentium®®

KK

PentiumPentium®® IIII

’’7575 ’’8080 ’’8585 ’’9090 ’’9595 ’’0000 ’’0505 ’’1010

PentiumPentium®® IIIIIIPentiumPentium®® 44

’’1515

Source: IntelSource: Intel

1,000,0001,000,000

100,000100,000

10,00010,000

1,0001,000

1010

100100

11

1 Billion 1 Billion TransistorsTransistors

80868086

8028680286i386i386

i486i486PentiumPentium®®

KK

PentiumPentium®® IIII

’’7575 ’’8080 ’’8585 ’’9090 ’’9595 ’’0000 ’’0505 ’’1010

PentiumPentium®® IIIIIIPentiumPentium®® 44

’’1515

The brick wall due to heating, fabrication cost, quantum mechanics …

Future challenges & opportunities: transportation, communication, energy, health care …

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

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

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

Thermal conductivity

HotTh

ColdTc

L

Q (heat flow)

Fourier’s Law for Heat Conduction

dxdT

kAL

TTkAQ ch

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