4. Conclusions
A graphite material is exfoliated to form graphene particles, and the
effect of nanoparticle volume fraction on the material properties of
inhomogeneous fluids with suspended graphene nanoparticles is
investigated at different temperatures or under oxidation conditions.
The present study aims to provide a fundamental understanding of the
thermal and viscosity properties of inhomogeneous fluids with suspended
graphene nanoparticles. Particular emphasis is placed upon the effect of
nanoparticle volume fraction on the material properties of inhomogeneous
fluids with suspended graphene nanoparticles. The major conclusions are
summarized as follows:
- The bottom-up approach produces low quantities with high quality and
large flakes. The top-down approach using graphite is low in cost and
yields a high concentration of suspended flakes, but fabricates
limited-size sheets with a low yield of mono-layer graphene.
- Smaller dispersions result in ease of addition of graphene to other
desirable emulsions to enhance the uniform coating matrix for
protection attributes graphene can provide to the coating.
- The pressure drop allows the liquid precursor to flow and homogenizes
the pass-through liquid of the liquid precursor that contains thin
layers of graphene such that the smaller graphene platelet particle is
well dispersed in the resultant fluid product.
- The phonon Raman scattering changes are correlated with structural
changes and defects associated with the hydroxyl and epoxy groups in
the basal plane and a variety of alkyl and oxygen-containing
functional groups terminating the edges.
- Graphene-containing nanofluids provide several advantages over the
conventional fluids, including thermal conductivities far above those
of traditional solid-liquid suspensions, a nonlinear relationship
between thermal conductivity and concentration, strongly
temperature-dependent thermal conductivity, and a significant increase
in critical heat flux.
- Stability of the nanoparticle suspension is especially essential for
practical industrial applications.
- Introduction of nanoparticles to the fluid changes density, thermal
conductivity viscosity, and specific heat.
- The functionalization process decreases enhancements in thermal
conductivity due to formation of surface oxides. In development of
nanofluids for heat transfer a fine balance needs to be obtained
between increases in thermal conductivity and viscosity.