Carbon Nanotube (CNT) Fins for Forced Convection Cooling of High Power Microprocessors

Carbon nanotubes (CNTs) have been reported to have very high thermal conductivity, ranging from 700 W/m-K to 3000 W/m-K. However, there are not many heat transfer applications where these CNTs are used. The two main reasons behind this are that, it is hard to grow the CNTs up to a macroscopic height and it is difficult to achieve good thermal contact between the CNTs and the surface of the heat source. We have overcome both these problems and obtained CNT bundles as tall as 2.5 mm and with different cross sectional areas that can be arranged in an array on a metallic substrate. Thus, these CNT bundles can act as fins having very high thermal conductivity to remove much higher heat flux compared to fins of similar dimension and configuration made of the customary materials such as copper or aluminum. Our calculation shows that in forced air convection cooling, a performance enhancement of 2 to 3 times can be achieved using just 2 mm tall CNT bundle fins, compared to a commercially available aluminum or copper heat sink that can remove a heat flux of 20-30 W/cm². That way we can achieve a better heat removal performance as well as a reduction in the size of the heatsink, without deviating much from the most convenient and widely used cooling technique