Consideration factors of Designing A heatpipe cooling Heatsink
The key component of the heatsink is the heatpipe. When the heating end begins to be heated, the liquid around the pipe wall vaporizes instantly and steam occurs. At this moment, the pressure of this part will increase, and the steam flow moves towards the condensing end under the traction of pressure. After the steam stream reaches the condensing end, it is cooled and condensed into liquid, which also releases a lot of heat together, and returns to the transpiration heating end by virtue of capillary force to complete a cycle.
At present, there are two main methods of heatpipe used in heatsink products: sintering and grooving. Compared with two sintered heat pipes of the same scale and grooved heat pipes, because there are many copper powders filled in the sintered heat pipe, the capillary radius of the heat pipe is small and the soaking power becomes low, which also leads to the decrease of the heat conduction function of the heat pipe when the length of the sintered heat pipe is added.
The grooved heat pipe has less filler, large capillary inner diameter and high permeability. Therefore, in the straight through state, the heat conduction power of the grooved heat pipe is stronger than that of the sintered heat pipe. The heat dissipation tube of any structure is very sensitive to the number of bends and the point of view of twists and turns, and each twists and turns will lead to the decline of the heat conduction function of the heat pipe. If we try to keep the diameter of the tortuous part unchanged, perhaps the change is very small, which can reduce the degree of function decline to a low level.
In addition to the tortuosity of the heat pipe, the parameter affecting the heat conduction function of the heat dissipation pipe is the size of the heat dissipation pipe. Now, 6mm or 8mm heat dissipation pipe will be selected for the main stream radiator. In fact, the increase of the diameter of the heat pipe brings the addition of the inner diameter of the capillary of the heat pipe, and the capillary permeability will be improved accordingly, which also improves the heat conduction power of the heat pipe.
However, More heatpipes or latger heatpipe diameter doesn't mean better thermal performance .It is also necessary to consider the touch area of the chip and the heat pipe. If the heating area of the heat pipe is uneven, perhaps the utilization rate of the heat pipe is too low to effectively improve the heat dissipation effect.
