  We present results of molecular dynamics (MD) calculations of the effective
thermal conductivity of nanofluids containing self-propelled nanoparticles. The
translational and rotational dynamics observed in the simulations follow the
behavior expected from the standard theoretical analysis of Brownian and
self-propelled nanoparticles. The superposition of self-propulsion and
rotational Brownian motion causes the behavior of the self-propelled
nanoparticles to resemble Brownian diffusion with an effective coefficient that
is larger than the standard Brownian value by a factor of several thousand. As
a result of the enhanced diffusion (and the convective mixing resulting from
the motion), we observe a discriminable increase of the effective thermal
conductivity of the solution. While the increases we observe are in the range
of several percent, they are significant considering that, without propulsion,
the nanofluid thermal conductivity is essentially not affected by the Brownian
motion and can be understood within the effective medium theory of thermal
conduction. Our results constitute a proof of concept that self-propelled
particles have the potential to enhance thermal conductivity of the liquid in
which they are immersed, an idea that could ultimately be implemented in a
broad variety of cooling applications.
