We present a theoretical model for explaining the enhancement in the effective thermal conductivity of nanotubes (cylindrical shape particles) for use in nanotube-in-fluid suspensions. We provide a good estimation for the nanolayers thickness which plays an important role in increasing the thermal conductivity. Our theoretical model shows that with the increase volume fraction of carbon nanotubes, the enhancement of thermal conductivity will be considerable if the thickness of nanolayers increases. We also show that the effective thermal conductivity is decreased with cylindrical nanoparticle diameter, which agrees with experimental results.
