Heat Sink Design and Fabrication T hermal E ngineering A nalysis M anufacturing -and- M anagement Ryan Condon Steve Gehlhausen David Keene Todd May Nathan Piccola

Outline Problem Description Design Process Methodology Design Description Fabrication Calculations Analytical Simulations Experimental Results Conclusion

Problem Description Cool CPU 100 Watts < 90 °C Material Al 6061-T6 Diameter = 4” Height = 2” Air V = 0.25 – 6.1 m/s T = 18.3 – 65.5 °C

Design Process – Methodology Maximize surface area Keep cylindrical Thin fins and spacing Look at boundary layers Design for higher air velocities

Design Process – Design Description 22 Fins Spacing = 0.125” Width = 0.60” Height = 1.5” Base = 0.5”

Design Process – Fabrication Tooling Limitations Many trips wasted time Cost Student = $ Professional = $ Environmentally friendly material Harmful Oils Non-recycling

Calculations - Analytical Challenging fin properties Excel allowed easy changes Steps 1.Define constants 2.Calculate R’s 3.Add R’s 4.Calculate Q’s 5.Calculate T’s

Calculations - Simulations ANSYS Icepak Import SolidWorks Enclosure wind tunnel Set variables Run simulation Points to collect data

Calculations - Simulations

Calculations - Experimental Holes for thermocouples Thermal grease Tape Highest power -> Lower power Highest velocity -> Lower velocity Steady state T < 1.0 C / min LabVIEW recorded data

Calculations - Experimental Heat sink was not mounted flat Limit 56 Watts

Results

Air velocity = 6.0 m/s

Results Power = 32.1 Watts

Conclusion Meets goals Suggested: 2m/s fan Too Expensive! Unless labor is free Improvements Mount properly Test lower velocities Adjust ambient temperature