The mechanism of boiling heat transfer of polycarboxylate superplasticizer modified stereotaxically constructed graphene water-based nanofluid: Experiment and molecular dynamics simulation

Abstract

The issue of heat dissipation is currently a challenge in industries such as manufacturing and microelectronics. The use of nanofluid for boiling heat transfer is an approach to solving this problem. However, the mechanism of heat transfer remains uncertain. In this study, stereotaxically constructed graphene (SCG) was modified with polycarboxylate superplasticizer (PS) to obtain modified graphene (PSG). PSG/water nanofluid (PSGNF) with high stability and excellent dispersibility was prepared. Boiling heat transfer (BHT) experiments were performed on PSGNF at three mass concentrations (0.01 wt%, 0.03 wt%, 0.06 wt%) and the corresponding boiling heat transfer coefficient (HTC) was calculated. The results show that, at a heat flux of about 300 kW m−2, HTC can achieve an enhancement of 332.0 % at the concentration of 0.06 wt%. To analyze the mechanisms, we combine experiments and molecular dynamics simulations. It is found that (1) the PSG particles deposited on the heated surface. The thinner deposited layer will promote heat transfer, while a thicker one will deteriorate it; (2) PSG particles can inhibit the merging of bubbles; (3) PSG particles can promote bubble formation.