Post on 08-Jan-2016
description
transcript
Shaun Heldt and Tyler Merrell
Background Most common type of
cooling method Keeps CPU at a safe
operating temperature Has fan to improve
overall heat transfer of fins by introducing forced convection.
Materials
1 Intel I7-26000K Processor heat sink
1 Fluke 51 Thermometer with K-thermocouple
1 Soldering Iron 1 Hot Glue Gun
Experiment
Used glue gun and soldering iron to simulate a hot CPU
Measured temperature of the center of the heat sink and the fin tip while heating
Measured time to cool after heated Compared with theoretical calculations
to solve for Qout and the required air velocity for forced convection
Data
25
27
29
31
33
35
37
39
0 50 100 150 200 250 300 350
Tem
pera
ture
(Cel
cius
)
Time (s)
Fin and Center Temperature During Heating
Center
Fin Tip
54
55
56
57
58
59
60
61
62
0 20 40 60 80 100 120 140
Tem
pera
ture
(Cel
cius
)
Time (s)
Center and Fin Cooling
Center
Fin
Natural Convection
Solve for Qout from natural convection of the heat sink to find if cooling due to natural convection is sufficient for cooling CPUs
Note: Qin from CPU equals 80W
Therefore, Qout must be greater than or equal to 80W for natural convection to be sufficient
Natural Convection
Thermal Circuit
Compiled Calculations
Qout= 6.77WTherefore, natural convection is not sufficient
Forced Convection Used forced convection calculations to
solve for required airspeed from fans to have a Qout = 80W
Using previous calculations, an h value of 143.138 W/m2 would be required to sufficiently cool the CPU
Using Hilpert’s equation for cross flow of a square geometry and thermophysical properties we found that the required airspeed velocity is 2.913 m/s
Conclusion
Approximations were made to form the model used in calculating the presented values, however, we believe that this model was a reasonable approximation of the system.
We found that forced convection through a heat sink is necessary in CPU cooling