Effects of spray-deposited oxidized multi-wall carbon nanotubes and graphene on pool-boiling critical heat flux enhancement

This paper examines the differences in critical heat flux (CHF) based on multi-wall carbon nanotubes and graphene have been found as new heat-transfer materials which are carbon allotropes with different shapes. The analysis of experimental data and results of calculations in pool-boiling critical heat flux experiments by spray-depositing oxidized multi-wall carbon nanotubes and graphene onto heat-transfer samples have been done to improve the economic efficiency and safety of the heat-transfer apparatus. The results show that the contact angle of the heat-transfer surface linearly decreased with spray deposition time, which resulted in an increased critical heat flux. The oxidized multi-wall carbon nanotubes and graphene showed maximum pool-boiling heat-transfer coefficients at 19.8° and 21.7°, respectively, while the pool-boiling heat-transfer coefficients decreased at angles of 9.9° or less and 12.5° or less, respectively. Also, the following new correction formula has been derived and compared with a current model by introducing a correction factor to Kandlikar's prediction model.