Thermal Science and Engineering From Macro to Nano in 200 Years
Avram Bar-Cohen
University of Maryland, Distinguished Univ ProfAIHTC, President

IHTC-15
15th International Heat Transfer Conference
August 10-15, 2014
Kyoto, Japan

Fourier Lecture Roadmap• Brief History of Heat Transfer• Genesis• Foundations of Conduction (Macro)• Foundations of Convection (Macro)• United States• Japan• Assembly of International Heat Transfer Conferences• Thermal Packaging of Electronics (Micro to Nano)Newton’s Principia (1687)• Transient heat transfer experiments• Devised linseed oil thermometer
Isaac Newton (1642-1727)• Rate of cooling proportional to temperature
difference (1701) – Newton’s Law of Cooling• Distinction between natural and forced convection
3Daniel Fahrenheit (1686-1736)
One of Fahrenheit’s Thermometers• Established thermometric standards for environmental measurements, 1714
• Fahrenheit’s thermometer consisted of vertical glass tube, filled with mercury• Temperature scaled to make environmental temperatures positive; divided
ǁĂƚĞƌĨƌĞĞǌŝŶŐƉŽŝŶƚ;ϯϮȗ&ͿƚŽďŽŝůŝŶŐƉŽŝŶƚ;ϮϭϮȗ&ͿŝŶƚŽϭϴϬƐĞŐŵĞŶƚƐ
4

Evaporation
Joseph Black (1728-1799)• Clear distinction between heat and temperature• Observed that each material has it’s own “capacity for heat”• Empirically quantified “latent heat” of fusion, later latent
heat of evaporation
5

ALAMY

1781 Watt Steam EngineHenry Howard

James Watt (1736-1819)

Father of Thermal Engineering• Applied Black’s observations to create efficient & powerful steam engine• Watt steam engine far more powerful than Newcomen steam engine• Separated condenser from body of engine• Ushered in the Industrial Age!
6

BBC

Joule’s paddlewheel and calorimeter, proved that heatand mechanical work are forms of energy
James Joule (1818-1889)• Discovered relationship between mechanical work and heat
• Officially refuted Caloric Theory with careful experiments• “Joule Equivalent” - mechanical equivalency of heat
• “Joule heating” with electricity• Experimentally confirmed 1st law of Thermodynamics (Energy Conservation)
7

Described three fundamental properties of heat flow:
1. Heat Capacity

2. Interior Conductibilityy

3. Exterior Conductibility (surface heat exchange)
Joseph Fourier (1768-1830)

Father of Thermal ScienceϴFourier’s Law

Joseph Fourier (1768-1830)• KďƐĞƐƐŝǀĞůǇŝŶƚĞƌĞƐƚĞĚŝŶŚĞĂƚƚƌĂŶƐĨĞƌĂĨƚĞƌũŽŝŶŝŶŐEĂƉŽůĞŽŶ͛ƐĂƌŵǇŝŶŐǇƉƚ;ϭϳϵϴͿ

• Fourier’s Law derived in On the Propagation of Heat in Solid Bodies ;ϭϴϬϳͿ
• Added heat transfer coefficient to Newton’s Law of Cooling9Heat Equation
The Analytical Theory of Heat
Joseph Fourier (1768-1830)• Fourier’s memoir revised into “Prize Essay” and won the Grand Prize in Mathematics

ĨƌŽŵƚŚĞ/ŶƐƚŝƚƵƚĞĚĞ&ƌĂŶĐĞŝŶϭϴϭϮ• General form of interior conduction derived in “Prize Essay”• Compilation of Fourier’s work published in ϭϴϮϮ͕The Analytical Theory of Heat

10

Navier-Stokes Equation of Motion

Energy Equation
C.L.M.H. Navier (1785-1836)

Stokes (1819-1903)• Navier-Stokes equation derived independently by Stokes (England) and Navier (France) inƚŚĞĞĂƌůǇϭϴϬϬ͛Ɛ• Energy equation was arguably ĚĞƌŝǀĞĚǁŝƚŚƚŚĞϭϴϯϯ&ŽƵƌŝĞƌ-Poisson differential equation11

ϭϴϴϭ: Lorenz• Buoyancy-induced convective transport
ϭϴϴϱ: Graetz• Thermal entrance region in pipe flow

ϭϴϰϮ: Reynolds• Laminar & turbulent flow
• Turbulent heat transfer
1904: Prandtl• Boundary layer concept• Mixing length model

Osborne Reynolds (1842- 1912)

1915: Nusselt• Convective heat transfer• Underlying dimensionless groups
1920’s-30’s: Max Jakob• Steam thermal transport – boiling & condensation

Ludwig Prandtl
Pranddtl (1875-1953)(1875-1953)
David K. Stone

12

Dimensionless Nusselt Number

Wilhelm Nusselt (1882-1957)• In 1907, received doctorate in Mech. Eng. from Munich Technical University, Germany• In 1915, published prominent paper: The Basic Laws of Heat Transfer• Proposed dimensionless groups in convective HT using similarity theory• Established a foundation for subsequent formidable advances in convective, radiative,
and two-phase heat transfer across the world13

J-Factor Analogy

Allan P. Colburn (1904-1955) [11]• First US Heat and Mass Transfer Effort: University of Delaware’s ChemicalEngineering Department• In 1936, Colburn published “Colburn Analogy” and heat transfer “J-Factor”• Colburn’s shell-and-tube HX research nurtured US HX industry

14Jet Propulsion Laboratory

New Mexico Museum of Space History

Theodore von Karman (1904-1955)• von Karman escaped Germany when the Nazi regime started purging Jewish
professionals in 1933
• Accepted Cal Tech’s invitation to become head of Guggenheim Aeronautics Lab,later renamed JPL• Created foundation for American rocket and missile technology• Founded Aerojet Corporation, advised NASA15

Jakobk b DimensionlesslNumberb

The Engines of Our Ingenuity

Max Jakob (1879-1955)• In 1936, fled Nazi Germany to avoid persecution, after illustrious 25 year career• Over 200 technical publications with profound heat transfer impact• /Ŷϭϵϯϴ͕ďĞĐĂŵĞƉƌŽĨĞƐƐŽƌŽĨDĞĐŚ͘ŶŐ͘Ăƚ//dĂŶĚĨŽƵŶĚĞĚƚŚĞ,ĞĂƚdƌĂŶƐĨĞƌLab• Textbook and a two-volume treatise on heat transfer had a profound influenceon heat transfer education and research in the United States16

Stothe P. Kezios (1921-2005)• “Mid-West” thermal engineering initially driven by Jakob at IIT• 1937-ϭϵϯϴ,ĞĂƚdƌĂŶƐĨĞƌůĞĐƚƵƌĞƐŝŶĨůƵĞŶĐĞĚƐĞǀĞƌĂůƉƌŽŵŝŶĞŶƚĂĐĂĚĞŵŝĐůĞĂĚĞƌƐ͗
Stoethe P. Kezioss (ITT), George Hawkins (Purdue), and Richard Jordan (Minnesota)• Kezios ďĞĐĂŵĞĐŚĂŝƌŽĨ,ĞĂƚdƌĂŶƐĨĞƌŝǀŝƐŝŽŶ;ϭϵϱϴ-59), 1st editor of ASME
Journal of Heat Transfer (1963), and ASME’s 96th president (1977-ϳϴͿ17

George A. Hawkins (1907-1978)• Hawkins drove from Purdue to IIT to attend Jakob’s 1937-ϭϵϯϴlectures• Dean of Engineering at Purdue from 1953 to 1967
• Established world class heat transfer program at PurdueϭϴRichard Jordan (1909-2002)

Ernst Eckert (1904-2004)• Jordan became head of Minnesota’s Mechanical Engineering Department (1950)• Persuaded Eckert to join department and establish the Thermodynamics andHeat Transfer Laboratory (THTL) at Minnesota in 1951
• THTL seminal contributions by E.M. Sparrow, Warren Ibele, Richard Goldstein, JamesHartnett, Patankar, Simon, Bar-Cohen,…
• Mid-West key to formation of AIHTC and ICHMT
19

web.mit.edu

William H. McAdams (1892-1975)

Warren M. Rohsenow (1921-2011)• “East Coast” thermal engineering initially driven by McAdams at MIT• Authored “Heat Transmission” in 1933 – primary teaching and reference book

• Warren Rohsenow joined MIT in 1946, established Heat Transfer Laboratory• Expanded research of boiling and condensation• Mentored numerous luminaries: Clark, Griffith, Mikic, Bergles, …….
20

Dittus-Boelter Correlation(Turbulent Pipe Flow)

Llewellyn M. K. Boelter (1898-1966)• “West Coast” thermal engineering initially driven by Llewellyn Boelter at UC Berkeley• Moved from EE to ME in 1923, formed heat transfer program with Floyd Cherry,
Harold Johnson, and Robert Martinelli,• Boelter produced analytic “Heat Transfer Notes” and Dittus-Boelter heattransfer coefficient correlation for Turbulent pipe flow
21

Thermopedia.com, data Nukiyama (1934)

Shiro Nukiyama (1896-1983)
Nukiyama curve, 0.14nmm platinum wire, water• Professor at Tohoku University from 1921 to 1956
• Pioneer in the understanding of boiling phenomena• Established the Nukiyama boiling curve in the 1930’s22

Yasuo Mori (1923-2012)• Professor of dŽŬǇŽ/ŶƐƚŝƚƵƚĞŽĨdĞĐŚŶŽůŽŐǇĨƌŽŵϭϵϲϭƚŽϭϵϴϯ• Significant impact on heat transfer community with a wide range of subjects:• Convective heat transfer, magneto-hydrodynamic power generation, plasma,high-temp, condensation, geothermal, and ocean thermal energy• Emphasized broad applications of thermal science and physics-based approach23

Beginning of IHTC:• “International Discussion on Heat Transfer”– London & Atlantic City, 1951

• “International Heat Transfer Conference” – Colorado, 1961
• Companion meeting for USSR researchers in London, 1962

• 4-Year IHTC cycle began with 3rd conference – Chicago, 1966
• Lead by Hartnett, Rohsenow, Eckert, Kezios, and Kutateladze• William Begell as publisher
IHTC14 – Washington, DC24

Avram Bar-Cohen
Conference Chair

Kyoto, Japan (2014)
Washington, DC, USA (2010)
Sydney, Australia (2006)
Grenoble, France (2002)
Graham De Vahl Davis
Conference Chair

Kyongju, Korea (1998)
Brighton, UK (1994)
Jerusalem, Israel (1990)

Geoffrey Hewitt

San Francisco, USA (1986)

Program Chair

Munich, Germany (1982)
Toronto, Canada (1978)
Tokyo, Japan (1974)
Versailles, France (1970)
Chicago, USA (1966)

Richard Goldstein
Conference Chair

Sam Sideman
Conference Chair

25

(18)

26

Birth of Thermal Packaging (1946)
Electronic Numerical Integratorand Computer (ENIAC)
••
•
•
•

5000 OPSϭϳ͕ϴϰϬǀĂĐƵƵŵƚƵďĞƐ
170kW
ϴϬ͛ǆϴ͕͛ϮϴƚŽŶƐΨϰϴϳ͕ϬϬϬ

http://ei.cs.vt.edu/~history/ENIAC.Richey.HTML

Electronic Numerical Integrator and Computer (1946)
27

Generations of Thermal Packaging
Gen-2a: Attached Coolers, ’80-…
Liquid Coldplate Era ‘80-’90• Maturation of bipolar devices: ~5W
Chips, ~300W Multi Chip Modules• Honeywell, IBM, CDC, Hitachi, NEC,Fujitsu, Cray,…

GOAL: Control temperature of“coldplate,” “coldbar,”…
IBM 3081 (1980)

IBM 3081 Water ColdplateϮϴGenerations of Thermal Packaging
Gen-2b: Attached Coolers, ’80-…
Heat Sink Era ’85-…
• Optimized heat sinks• Improved TIM’s• Air flow paths

GOAL: Reduce øca “case-to-air”
resistanceFujitsu 8 CPU Air-Cooled Board (1985)

29

Air-Cooled Heat Sinks(a) Bonding(b) Folding(c) Die-Casting(d) Forging(e) Skiving(f) Machining30

Microprocessor Hot Spots• q”hot spot = 500 W/cm2 (2 x 2 mm)• q”avg. = 50 W/cm2 (40 x 40 mm)

S.M. Sri-Jayantha, G. McVicker, K. Bernstein, J.U. Knickerbocker IBM Journal,Res & Dev, 2008, Vol 52, No 6

On-Chip Hot Spots in IBM 3D Chip Stack
31

Chip Heat Flux Challenge
100kPower Amplifier
Hot Spots

Heat Flux (W/cm²)

10k

On Sun’s surface
Logic Chip
Hot Spots

1k

Ballistic entry

100Nuclear blast
Logic Chip
AverageReentry from earth orbit

10
Rocket motor case

10.1

Solar Flux On Earth’s surface

0.01
01,000

2,000

3,000
4,000
5,000
Temperature (K)Heat Fluxes for Chips and Other Thermal Engineering Hardware

6,00032

3D Chip Stacks(Dereje Agonafer and Bahgat Sammakia, InterPACK’05)

Typical 3D Chip Stacks (2005)
33

Chip Heat Density Challenge
Chip Stack

Liquid Metal nuclear
reactorLight-water nuclear
reactorMercury Vapor
lamp

Halogen bulb

Cray-3 Module
SX-3 Module

Home light bulb
IBM TCM Module
Electric stove
Human brain

Heat Densities for Chip Stacks and Other Thermal Engineering Hardware

34

Near-Junction Nano Thermal Transport (NJTT)
Vision: Provide
localized thermal
management within
the device substrate
to increase Power,Speed, Reliability

High Thermal Conductivity Over-layer for Heat
Removal from Topside of Devices• High thermal conductivity in deposited material• Conformal coverage with no gaps

GateSourceDrain

High Thermal Conductivity
Substrates

Anisotropic Heat Transport• Integrate lattice-mismatched heatspreaders• Eliminate thermal interface resistance• Match coefficient of thermal expansionof electronic material

Embedded Thermal Vias~ 1um thickness• Efficient nanoscale phonon channel• Long LO phonon lifetime (3ps)• Extremely low electrical contact
resistance

Substrate• Micro-machined vias within ~1 micronof junction• High thermal conductivity conformal fillmaterials• Low coupling resistance for junction-tothermal via, thermal via-to-heat sink

Active Liquid Cooling• Eliminate impact on device
electrical properties due to timevarying dielectric constant of liquid

Distribution Statement A, Approved For Public Release, Distribution Unlimited

35

Intrachip:• Cooling fluid flowing through microchannels
fabricated directly into chipInterchip:hi• Cooling fluid flowing through the microgap
between chips in 3D chip stacks• Highly Efficient Cooling• Chip Heat Flux > 1kW/cm2• Chip Temperature Rise < 30K• Hot Spot Heat Flux > 5kW/cm2• Hot Spot Temperature Rise < 5K
Program Objective:• Provide the fundamental thermofluid
building blocks for the utilization of Intraand Interchip evaporative cooling in 3D
DoD electronics
36

Towards an Embedded Cooling Paradigm
Challenges:•Complete the Inward Migration of Thermal Packaging•Extract heat directly from device, chip, and package•

Place thermal management on an equal footing with functional design andpower delivery

Benefits:•Allow electronic systems to reach material, electrical, optical limits•

Reduce SWaP-C for comparable performance•

Lead the way to integrated, intelligent system co-design

Enabling Technologies:•

Microfluidics – convective and evaporative•

Thermal interconnects – active/passive•

Microfabrication – channeling, hermeticity•

Thermal Co-Design
37
Distribution Statement A, Approved For Public Release, Distribution Unlimited

Concluding Remarks• Long and illustrious history for internationalthermal science and engineering (TSE)• AIHTC plays key role in nurturing community• d^ĞĨĨŽƌƚƐƐƚĂƌƚĞĚŝŶϭϴϬϬ͛ƐǁŝƚŚ^ƚĞĂŵŶŐŝŶĞƐ͕
Furnaces, and moved to HVAC, Gas Turbines, andSatellites• Microelectronics and microfabrication pushed
TSE to micro-scale• Embedded Cooling and nanofabricationnecessitate TSE R&D and design at nano-scale.

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Born, NYC 1935
SB, SM -1958, PhD 1962, MIT
Married Priscilla, “Penny,” Maule 1960
Ford Asst Prof, Mech Eng, MIT 1963
Professor, Mech Eng, Ga Tech, 1969
Chair, Mech Eng, Iowa State, 1972
Professor, Mech Eng, RPI, 1986
Dean, College of Eng, RPI, 1989-1992
President, ASME, 1990-1991
NAE member, 1992
Published 400 papers, 26 books
Graduated 82 PhD and MS students
Survived by wife Penny, sons Eric andDwight, and 5 grandchildren
AEB: “Two are better than one…”
Ecclesiastes, 4:9

Thank You !!

Tel Aviv University | School of Mechanical Engineering

In Memory of:Professor Yoram Zvirin (1942 – 2013)
Mechanical Engineering, Technion- Israel Institute of Technology
Academic and public service
Head, Technion Transportation Research InstituteHead, Internal combustion engines lab
Director, Israel National Museum of Science
Chairman, Solar World Congress 1999 (Jerusalem)
Secretary, Assembly of IHTC 9, Jerusalem, Israel 1990
ICHMT Scientific Council

IHTC15Aug. 2014

41

Interest areas and contributions
Combustion, fuel efficiency, alternative fuels, emissions
Transportation systems, autonomous vehicles, environmental impacts
Radiative heat transfer, conjugate heat transfer
Solar collectors, Natural convection in thermosyphonsBirth of Thermal Packaging (1946)
Electronic Numerical Integrator
and Computer (ENIAC)•••••

5000 OPSϭϳ͕ϴϰϬǀĂĐƵƵŵƚƵďĞƐ
170kW
ϴϬ͛ǆϴ͕͛ϮϴƚŽŶƐΨϰϴϳ͕ϬϬϬ

http://ei.cs.vt.edu/~history/ENIAC.Richey.HTML

Electronic Numerical Integrator and Computer (1946)
42

Chip Power Dissipation

Chip Power Dissipation – iNEMI Roadmap
43

Aurthur Bergles (1935-2014)

Avram Bar-Cohen• HT at MIT progressed with: John A. Clark, Peter Griffith, Bora Mikic, and Arthur Bergles• Avram Bar-Cohen – Distinguished UMD Professor – completed PhD with Art Bergles in1971• In 1992, John Lienhard V upgraded MIT’s heat transfer laboratory• Renamed the Rohsenow Heat and Mass Transfer Laboratory
44

ICECool Technologies
SOA: Remote Cooling

ICECool: Intrachip/Interchip Cooling• Heat removed far from chip• >ŽǁѐdĨŽƌŚĞĂƚƚƌĂŶƐĨĞƌƚŽĂŵďŝĞŶƚ
• Limits power dissipation• Contributes to high SWaP

• Heat is removed at the chip• ,ŝŐŚѐdĨŽƌŚĞĂƚƚƌĂŶƐĨĞƌƚŽĂŵďŝĞŶƚ• Overcome SOA component thermal limits
On-Chip TECs
• Reduces SWaP

Heat Dissipated (W)Evaporative Microfluidics
High k materials forvias/interconnects

Source:Nextreme

Manifold Microcooler

Serizawa and Feng (2001)

Source: UMD
Source: Wikipedia

Balandin (1999)

Areas of Focus• Integrated Microfluidics• Thermal Substrates and Interconnects• Thermal Co-Design

Technology Goals• GaN MMIC PAs with 10x output power• Microprocessors with up to 10x frequency
45

Distribution Statement A, Approved For Public Release, Distribution Unlimited

Generations of Thermal Packaging
Gen-1b: Rack Cooling ‘64-’85• DIP’s and SMT’s on PCB’s• PCB’s in Card Cages

GOAL: Control rack air temperature

IBM 360 (1982)

PCB “Card Cage”
46

“Triple Threat”
Nanoelectronics Era, 2000-…
• GHz-level CMOS with features below 100nm• Power dissipation increasing, distinct on-chip “hot spots” on Si/compound semiconductors• Emergence of homogeneous/heterogeneous “chip stacks” denying access to back of chipfor “thermal solution”

High Power

heat sink

GOALS:• Remove large flux
• Reduce/eliminate on-chip “hot spots”• Extract high heat density

heat sinkheat spreader

chip carrier

Hot Spots
3-Dimensional
Triple Threat47