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ME156C Mechanical Engineering Design

ME156C Mechanical Engineering Design. The main objective of this course is to provide ME seniors with an opportunity to approach engineering practice through a design problem, whose solution requires - knowledge-based innovation and integration;

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ME156C Mechanical Engineering Design

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  1. ME156C Mechanical Engineering Design The main objective of this course is to provide ME seniors with an opportunity to approach engineering practice through a design problem, whose solution requires - knowledge-based innovation and integration; - independent thinking and problem-focusing research; - effective use of engineering analysis skills; - team work within time/resource constrains. The main theme of the ME-156C course and design projects is thermo-fluid design in support of the human exploration and development in space and planetary bodies Why space? Why thermal/fluid?

  2. Space operations and applications • - space travels (spacecrafts, including new generation of micro- and nano-spacecrafts); • - human explorations and developments in the Moon, Mars, and other planets (power generation and storage, life support, materials production and storage, etc.). • For space applications, design is of utmost importance because • Low mass, compactness • Efficient energy use and power regeneration • Reliability, minimum maintenance • High-cost technologies developed for aerospace applications have also gradually penetrated commercial markets and benefited consumers.

  3. Reliable, less maintenance PASSIVE SYSTEMS Energy efficient On Earth, g Natural convection Boiling heat transfer Does not fully apply to space Mars 0.380 g Moon 0.169 g Europa 0.140 g Phobos (Mars) 0.0008 g Intercontinental 0 g Empirical knowledge of thermo-fluid processes obtained on Earth fails to serve as scientific base for space-related designs Design needs drive frontier research and innovation

  4. Theme of 2001 Spring quarter Stegosaurus(STEG-oh-SAWR-us) North America – Late Jurassic Period (150 million years ago) 30 feet long and 6,800 pounds, with 17 bony heat plates for controlling body temperature. Smallest brain-to-body mass ratio IBM PowerPC MCM (Multichip Module) North America – Late 20 century 2 inches long

  5. Thermal Management of Electronics Devices Reliability and life expectancy of electronic equipment are related to the component thermal regime, as physical failure mechanisms are dependent on (absolute) temperature (85- 125o C) and temperature gradients (minimum temperature variation and thermal stress). Light BulbBGA Package Power dissipation 100 W 25W Surface area 106 cm2 1.96 cm2 Heat flux 0.9 W/cm2 12.75 W/cm2 Dissipation domain Room cm3 Power dissipation in today’s technology (700 MHz): 250 W ? in few years (10 GHz) 1000…2500 W ?

  6. Chip Power increasing by three orders of magnitude, from 0.1-0.3 W (in 60’s) to 15-30 W (in 90’s), and expected to reach 150 W in 2005 (50 chips x 3 W) Intel Pentium II: 15 W/cm2 Digital Alpha AV6: 20 W/cm2 HP Chip: 80 W/cm2 Intel (Adv.): 100 W/cm2 MOSC Thyristor: 200 W/cm2 Power Electronics: 300 W/cm2 Laser Diode: 500 W/cm2

  7. Electronics Cooling Challenges Increasing processor power (high speed system, multichip module design and packing) Miniaturization (high power density, low weight) Reliability requirement (precise thermal regulation) Customer-driven and application-specific requirements (more plastic, no noise, EMC, low power consumption in laptops, specific conditions in auto, appliance, avionics, military and space applications– vibration, acceleration, microgravity, etc.) Thermal Packaging vs. Electronics Packaging

  8. Electronics Cooling Technologies Heat chain: Source - Extraction - Transfer – Sink For low heat fluxes (< 10 W/cm2) Air cooling (3…5 W/cm2) Heat pipes (5…10 W/cm2) For intermediate heat fluxes (10…20 W/cm2) Water cooling Air jet impingement Heat pipes (special design and operating conditions)

  9. High Heat Flux Engineering (20…40000 W/cm2) High-velocity jet impingement (up to 40000 W/cm2) -        100 m/s circular liquid jet (MIT) Pool boiling and flow boiling (20…27600 W/cm2) -        Immersion of chips in coolant (liquid nitrogen, FC, water) -        Microchannel heatsinks (LLNL, 1000 W/cm2) -        Subcooled flow boiling in narrow channels (PU, 27600 W/cm2) Methods may satisfy the heat-flux requirement, but fail to satisfy the maximum temperature requirement

  10. Miniature heat pipes (20…300 W/cm2) -        Pulsating heat pipes -        Inverted meniscus design Spray cooling, droplet impingement (100…200 W/cm2) -        Complete evaporation of micro-droplets on heated surface Heat pipe-assisted spray MEMS-assisted cooling system - microjet cooling (EM or piezoelectric drivers) - micropump-assisted heat pipe Solid-state heat pipes Magnetocaloric materials as the refrigerant Thermoelectric cooling materials

  11. Theme of 2001 Spring quarter P P C Osmotically pumped module (Hughes, CA)

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