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. Our theoretical model shows that with the decrease of nanotube diameter, the thermal conductivity increases 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. We provide a good estimation for the nanolayer’s thickness which plays an important role in increasing the thermal conductivity
