A dissipative particle dynamics two-component nanofluid heat transfer model: Application to natural convection

The current paper presented a novel two-component dissipative particle dynamics (DPD) model to investigate heat transfer enhancement in natural convection using Al₂O₃-water nanofluid. This DPD model used two different types of particles to represent the base fluid particles and the nanoparticles. The energy and momentum interaction between nanofluid particles were incorporated within the new DPD model via modifying the DPD collisional heat flux and the friction parameter, respectively. The model was used to investigate the effect of nanoparticle volume fraction on heat transfer enhancement within the cavity. The study covered a wide range of nanoparticles (1% ≤ φ ≤ 7%) and three Rayleigh numbers were considered, which are Ra = 10⁴, Ra = 5 × 10⁴, and Ra = 10⁵. In general, the DPD results reported a minor deterioration in heat transfer due to the presence of nanoparticles. By looking at the local distribution of enhancement along the hot wall of the cavity, it was found that, for high Rayleigh numbers, most parts of the hot wall experienced deterioration in heat transfer accompanied with some enhancements that were registered near the top wall of the cavity. Also, the results revealed that for the case of low Rayleigh numbers some enhancements were observed using low volume fraction of nanoparticles (φ ≤ 4%), however further increase in volume fraction of nanoparticles caused a deterioration in heat transfer.