Efficient natural-convective heat transfer properties of carbon nanotube sheets and their roles on the thermal dissipation.

In this work, we report our studies related to the natural-convective heat transfer properties of carbon nanotube (CNT) sheets. We theoretically derived the formulas and experimentally measured the natural-convective heat transfer coefficients (H) via electrical heating method. The H values of the CNT sheets containing different layers (1, 2, 3, and 1000) were measured. We found that the single-layer CNT sheet had a unique ability on heat dissipation because of its great H. The H value of the single-layer CNT sheet was 69 W/(m(2) K) which was about twice of aluminum foil in the same environment. As the layers increased, the H values dropped quickly to the same with that of aluminum foil. We also discussed its roles on thermal dissipation, and the results indicated that the convection was a significant way of dissipation when the CNT sheets were applied on macroscales. These results may give us a new guideline to design devices based on the CNT sheets.