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Evaluating the Usefulness of a Heat Sink using SOLIDWORKS Simulation
  • Evaluating the Usefulness of a Heat Sink using SOLIDWORKS Simulation

    Posted on Apr Mon, 2016 by seacad_admin

    Heat Sink are useful tools when it comes to dissipating heat away from a heat source. Depending on the:

    1. Thermal Resistance of Materials
    2. Airflow around heatsink
    3. Fin Density
    4. Fin Spacing
    5. Width
    6. Length

    and many other parameters, you may get different results in terms of heat dissipation. So the goal should always be determined before choosing a heat sink, such as the volume in which the heat sink can occupy, and what is the final temperature of the heat source if the specific heat sink is used.

    Heat Sink in different shapes, sizes, and fan functionality

    However that may be difficult to determine. Most heat sink providers may provide data about the heat sink capabilities, but the data may be based on an ideal environment. But what if you want to know how the heat sink performs in your unique environment?

    What will the temperature of the processor be if it outputs 5 Watts with the heat sink on top?

    Well let’s find out. First we will do a base lining to see if SOLIDWORKS Simulation is giving us the right calculation. Assuming that the chip at the bottom has an output of 5 Watts for 100 seconds with the chip at an initial temperature of 20 C°, using the Heat Generation formula:

    Whereby:

    Q = Energy in Joules

    m = mass of object in kg

    c = specific heat capacity in j/(kg*C)

    T = Change in temperature

    We get that the final temperature will be 30 C°. The inputs are as such:

    • Mass: 0.069196kg (density of TSSOP Material)
    • Heat Capacity: 700j/kg*c (TSSOP Material)
    • Initial Temperature: 20.05 C
    • And energy does not escape the object

    Now inputting the same information into SOLIDWORKS Simulation, we get the temperature profile as such:

    Here we see that SOLIDWORKS does give us a reasonable results with heat dissipating faster at the ends due to the convention effect!

    Now let’s put everything together. Assuming we apply a 5 Watt output until steady-state is reached, we get the following results WITH and WITHOUT a heat sink:

    Here we see that the heatsink allows the processor to operate at a lower temperature of 95 C° compared to when there is no heat sink which is 134 C°.

    The heat sink works!

    Looking at the air profile, we can see how the heat sink effectively increases the surface area for heat dissipation through convention, thus allowing the processor to perform at lower temperature:

    Heat Sink works best when there is an airflow going through the heat sink. We can study that too! Here are the results with an airflow of 0.5m/s:

    Here we see with the heat sink, the processor can operate at a lower temperature of 21.30 C° compared to 37 C°. Not only that, the heat sink allows for an even distribution of temperature across the surface which is important for efficient operations for certain CPUs and chips.

    In summary the results are as such:

    No Heat Sink With Heat Sink
    No Wind 133.84 C 95.38 C
    With Wind (0.5m/s) 37.13 C 21.32 C

    And all of this can be done within minutes! The next step would be to keep testing with different heatsink designs till the final temperature of your heat source is met. If you would like to know more, contact us at +65 6372 1416 or email marketing@seacadtech.com.

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