6. Nanofluids

The search for fluids with improved thermal characteristics has led to the pre-industrial development of a new type of fluid: nanofluids.

Crystalline solids have thermal conductivities that are generally 1 to 3 orders of magnitude higher than those of fluids (figure 5 ). Thus, the conductivity of a fluid can be significantly improved by the addition of suspended solids. The thermal conductivity of fluids containing suspended solids has been studied for a long time, ever since Maxwell's work was published 100 years ago. However, with very few exceptions, the studies carried out on particle suspensions in a fluid concerned millimetre- and micrometre-sized particles. Building on these old ideas, it has been proposed to manufacture...