Boiling flow of graphene nanoplatelets nano-suspension on a small copper disk

• Autor(a) principal: Goodarzi, Marjan
• Data de Publicação: 2021
• Outros Autores: Tlili, Iskander, Moria, Hazim, Cardoso, E. M. [UNESP], Alkanhal, Tawfeeq Abdullah, Anqi, Ali E., Safaei, Mohammad Reza
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.powtec.2020.08.083; http://hdl.handle.net/11449/205165
• topic: Graphene oxide; Nano-suspension; Nanoplatelets; Particulate fouling; Thermal evaluation

In the present work, an attempt was made to experimentally quantify the boiling heat transfer coefficient (BHTC) of graphene oxide-water nano-suspension (NS) inflow boiling heat transfer regime. The NS was prepared at weight fractions of 0.025, 0.05, and 0.1% using the two-step method and further stabilized for 17 days (at wt% = 0.1). Results showed that the presence of graphene oxide nanoplatelets (GNPs) imposed an extreme fouling thermal resistance (FTR) to the surface, which caused a reduction in the BHTC over 1000 min of continuous operation after the CHF point. This was mainly due to the presence of the graphene oxide on the surface, which created a surficial fouling layer and heat accumulation on the surface. Instead, the sedimentation layer promoted the critical heat flux (CHF) point such that the point for water was 1370 kW/m2 reaching 1640 kW/m2 for NS at wt% = 0.1. Likewise, the highest BHTC of 17.4 kW/(m2K) at Re = 10,950 was obtained. Also, with increasing the heat flux and flow rate, the BHTC increased. The same trend was also identified with a mass fraction of GNPs up to CHF point. The increase in the BHTC was attributed to the intensification of the Brownian motion and thermophoresis effect in the boiling micro-layer close to the surface.