Pool boiling on defective graphene-coated surfaces: A molecular dynamics study

Proven to have superior mechanical and thermal properties, graphene has the potential to enhance the boiling heat transfer performance as a coating material. As defective graphene is inevitably produced together with pristine graphene, however, it is more practical to examine the impact of defective graphene. In the current work, a molecular dynamics simulation was adopted to investigate water pool boiling on copper substrate coated with five types of stable defective graphene monolayer. The results show that most of the cases coated with defective graphene have higher initial heat flux and reach equilibrium faster than the pristine graphene-coated case under the isothermal heating condition. Nevertheless, the percentage of pentagon-heptagon defect in the graphene unit cell does not have a clear correlation with its heat transfer performance. In particular, all the graphene coatings enhance the critical heat flux (CHF) value for water boiling by nearly two orders of magnitude, regardless of defectiveness. This is of practical significance to enable graphene thermal management applications.