Thermal Conductivity Evaluation of the Carbon-Based N anofluids with Photoacoustic Approach

The paper is devoted to the investigation of thermal transport properties of several types of carbon-based nanomaterials, namely graphene oxide and carbon nanodots fabricated with two different approaches. As the basic liquids we investigated water and polyethylene glycol. Specifically, the latter liquid belongs to the phase change materials, and it is promising for the application for thermal energy storage. We observed nonlinear rise of thermal conductivity of nanofluids with increasing of the volume fraction. Such nonlinear rise of thermal conductivity could be explained by influence of the interfacial nanolayer between the particles. This was taken into account for the effective thermal conductivity model. Specifically, to the effects of nanolayer thickness, nanoparticles size, volume fraction, and thermal conductivities of basic fluid, nanoparticles, and nanolayer were considered.