During communication with the customer, our engineers aimed to solve a heat dissipation issue for a smart wear communication device using a natural convection scheme. Although the overall power of this device is not high, the space provided by the customer was very limited. Ultimately, we designed both graphite material and sheet metal structure heat sink to successfully resolve the problem.
Customer’s design requirements and product parameters:
System Conditions :
•Thermal Power:5.3W;
•Thermal glue( thermal conductivity) =0.98W/m.k
• Sic Ceramic heatsink( thermal conductivity) =14W/m.k
• PCB Therml conductivity=10.0W/m.k
•Sic Ceramic /30mm X 30mm X 7mm
•Nylon material for case shell
•Natural convection heat dissipation
•Environment 45℃
Setting Basic Parameters.
•The ambient temperature is 45 ℃.
•Thermal radiation is being considered.
•Laminar flow regime.
•Gravity vector in the y direction.
•Natural convection operates at a pressure of 101325N/m2.
•The number of meshes is 752 154. Set uniform mesh parameters for each assembly and allow multi-level meshing with minimumgap changes.
•A cloud map showing the overall temperature distribution of the product indicates a maximum temperature of 88.5 ℃.
The Sic ceramic heat sink, with a black surface, has a radiation factor of 0.85 and a maximum temperature of 87.6℃.From the temperature distribution of this picture, it is found that the temperature distribution of graphite heat sink is relatively uniform.
The temperature distribution corresponding to these components is shown.Among them, the temperature of the CPU is relatively high, 88.5 degrees, and the customer’s requirement of 90 degrees below is qualified.
In the design process, our engineers also found that increasing the surface area of the chip heat dissipation is also a good way, so we tried a heat sink processed with sheet metal parts, and found that the temperature of the chip is reduced to about 70 degrees , from which we draw a conclusion that a natural heat dissipation heat sink, a very important factor is the surface area, the larger the surface area, The more heat it radiates.
Therefore, graphite heat sink can also be widely used in the field of electronic heat dissipation, its advantage is high longitudinal heat conductivity, at the same time, the manufacturing process is simple, suitable for mass production, so the cost is relatively high.
