Enhanced thermal conductivity and
viscosity of copper nanoparticles in ethylene glycol nanofluid
by Garg, J., Poudel, B., Chiesa, M., Gordon, J.B., Ma, J.J., Wang, J.B., Ren, Z.F., Kang, Y.T., Ohtani, H., Nanda, J., McKinley, G.H. and Chen, G., J. App. Phys, 103, (2008), 074301.
This study investigates the thermal conductivity and viscosity of copper nanoparticles in ethylene
glycol. The nanofluid was prepared by synthesizing copper nanoparticles using a chemical reduction
method, with water as the solvent, and then dispersing them in ethylene glycol using a sonicator.
Volume loadings of up to 2% were prepared. The measured increase in thermal conductivity was
twice the value predicted by the Maxwell effective medium theory. The increase in viscosity was
about four times of that predicted by the Einstein law of viscosity. Analytical calculations suggest
that this nanofluid would not be beneficial as a coolant in heat exchangers without changing the tube
diameter. However, increasing the tube diameter to exploit the increased thermal conductivity of the
nanofluid can lead to better thermal performance.