Search Results

The addition of metal nanoparticles to standard coolant fluids dramatically increases the thermal conductivity of the liquid. The properties of the prepared nanofluids will allow for lighter, smaller, and higher efficiency spacecraft thermal control systems to be developed. Nanofluids with spherical or rod-shaped metal nanoparticles were investigated. At a volume concentration of 0.5%, the room temperature thermal conductivity of a 2 nm spherical gold nanoparticle-water solution was increased by more than 10% over water alone. Silver nanorods increased the thermal conductivity of ethylene glycol by 53% and water by 26%.

The addition of metal nanoparticles to coolants used in thermal control systems can dramatically increase the thermal conductivity of the base fluid. Such metal nanoparticle-fluid composite materials are referred to as nanofluids and their use as coolants has the potential to reduce the weight and power requirements of spacecraft thermal control systems. The thermal conductivity of nanofluids is dependent on the concentration, size, shape, surface chemistry, and aggregation state of the constituent nanoparticles. The effects of nanoparticle loading concentration and the aspect ratio of the nanoparticles on the thermal conductivity and viscosity of water and ethylene glycol based coolants were investigated. Silver nanorods with a diameter of 55 ± 12 nm and an average length of 12.8 ± 8.5 μm at a concentration of 0.5% by volume increased the thermal conductivity of water by 68%.