Atomistic Investigation\nof Viscoelastic Nanofluids\nas Heat Transfer Liquids for Immersive-Cooling Applications

A comparative assessment of the thermal properties and\nheat transfer\ncoefficients achieved by viscoelastic nanofluids suitable for immersion\ncooling is presented, with the candidate samples exhibiting distinct\ndifferences based on the nanoparticle chemistry and shape. Molecular\ndynamics simulations of different nanoparticles such as copper nanosphere,\ntwo-dimensional pristine graphene, and single-walled carbon nanotube\n(CNT) dispersed in PAO-2 of concentrations of approximately equal\nto 2.6% by weight are performed in the present investigation. While\ncarbon-based nanoparticles increase the specific heat capacity of\nthe nanofluids, copper-based nanofluids show a decrease in the corresponding\nvalues. Moreover, the heat conduction in copper-based nanofluids is\ndependent on the higher degree of phonon density of states (DOS) matching\nbetween the copper and solvent atoms, whereas the high intrinsic thermal\nconductivity of graphene and CNT compensates for the lower degree\nof DOS matching. The addition of an OCP polymer chain to impart viscoelasticity\nin the nanofluids exhibits a heat transfer coefficient enhancement\nof more than 80% during Couette flow as a result of chain expansion,\nindicating their suitability for immersive-cooling applications.