Micro/Nanoscale Heat Transfer

Light-emitting diode cooling via nucleate boiling using graphene-nanoplatelets coatings

This study aims to investigate the nucleate boiling enhancement achieved using graphene nanoplatelets (GNPs) coatings. The efficacy of light-emitting diode (LED) cooling is anomalously augmented by deploying nucleate boiling on GNPs coated surface at sub-atmospheric pressures. The ultrafast transport of water molecules through the nanostructures of GNPs forms an ultrathin film of water that prompt effective absorption of latent heat of vaporization. Concurrent with the nanoporous structure of graphene-nanoplatelets, the nucleate boiling performance is significantly augmented due to the pronounced enhancement in the nucleation, growth, and departure rates of vapor bubbles.

This study aims to investigate the nucleate boiling enhancement achieved using graphene nanoplatelets (GNPs) coatings. The efficacy of light-emitting diode (LED) cooling is anomalously augmented by deploying nucleate boiling on GNPs coated surface at sub-atmospheric pressures. The ultrafast transport of water molecules through the nanostructures of GNPs forms an ultrathin film of water that prompt effective absorption of latent heat of vaporization. Concurrent with the nanoporous structure of graphene-nanoplatelets, the nucleate boiling performance is significantly augmented due to the pronounced enhancement in the nucleation, growth, and departure rates of vapor bubbles.

Figure: Effective LED cooling achieved via nucleate boiling on superhydrophilic GNPs coatings

Performance enhancement of graphene-coated micro heat pipes for LED cooling

The rate of water transport through graphene nanocapillaries is profoundly enhanced compared to that in microscale capillaries due to the prevalence of exceptionally high capillary pressures and large slip lengths. As an inaugural study, we integrate graphene nanocapillaries into a micro heat pipe for enhanced LED cooling. With the use of graphene nanocapillaries, the ultrafast water transport synergically enhances the water circulation and evaporation process in the microfluidic device.

Figure: Schematics of working mechanism of (a) an uncoated micro heat pipe, (b) a micro heat pipe coated with GNPs nanocapillaries. (c) The ultrafast transport of water molecules through the graphene nanocapillaries.

Thermal performance enhancement of two-phase closed thermosyphon with graphene-nanoplatelets coatings

The enhancement of phase-change heat transfer in the two-phase closed thermosyphon (TPCT) coated with graphene-nanoplatelets (GNPs) of different wettability is investigated. The intrinsically hydrophobic GNPs can be modified to become superhydrophilic through a simple thermal curing process. The performance of a TPCT is governed by three major processes, namely evaporation, condensation and circulation of condensate. By benchmarking with the uncoated TPCT, we experimentally examine the thermal enhancement and comprehend the thermal characteristics of the GNPs-coated TPCTs with different wettability.

Figure: Schematic diagrams of the working mechanism of the uncoated, uncured-GNPs coated and cured-GNPs coated TPCTs.

Dr Hung Yew Mun

Dr Hung heads the Micro/Nanoscale Heat Transfer research team in the Mechanical Engineering Research Laboratory at Monash University Malaysia. His main research areas focus on micro-scale heat transfer, phase-change heat transfer, electronics cooling and interfacial phenomena of carbon and graphene nanostructures.

Current GRS

Mr Lim  Chang  Sheng

Chang Sheng obtained his Bachelor of Mechanical Engineering (Hons) from Monash University in 2017. He is currently pursuing a PhD at Monash University Malaysia. His work focuses on the tunable wettability of graphene nanostructures in two-phase heat transfer applications.

Mr Sia Geng Di

Geng Di obtained his Bachelor of Mechanical Engineering (Hons) from Multimedia University in 2017. He is currently pursuing a PhD at Monash University Malaysia. His work focuses on the subcooled flow boiling on graphene nanostructured surfaces with tunable wettability.

Mr Ng Ving  Onn

Ving Onn obtained his Bachelor of Mechanical Engineering (Hons) from Monash University in 2018. He is currently pursuing a PhD at Monash University Malaysia. His work focuses on the heat transfer enhancement of phase-change heat transfer devices using graphene nanostructures with tunable wettability.

Mr Edmund Ng Chong Jie  

Edmund obtained his Bachelor of Mechanical Engineering (Hons) from Monash University in 2019. He is currently pursuing a PhD at Monash University Malaysia. His work focuses on the heat transfer enhancement of microchannel heat sinks using graphene nanostructures with tunable wettability.

Mr Lim Yi Shen

Yi Shen obtained his Bachelor of Mechanical Engineering (Hons) from Monash University in 2019. He is currently pursuing a Master of Engineering Science at Monash University Malaysia. His work focuses on the light-emitting diode cooling via nucleate boiling using graphene-nanoplatelets coatings.

Alumni

Dr Kueh Tze Cheng

Dr Kueh Tze Cheng obtained his Bachelor of Engineering (Mechanical Engineering) and Master of Engineering Science from Multimedia University in 2012 and 2016, respectively. Subsequently, he obtained his PhD from Monash University Malaysia in 2021. His PhD research focused on the investigation of ultrafast water transport mechanism through graphene nanostructures using molecular dynamics simulations.

Mr Johnathan Goh Yue Herng

Johnathan obtained his Bachelor of Mechanical Engineering (Hons) from Monash University in 2018. Subsequently, he obtained his Master of Engineering Science from Monash University Malaysia in 2021. His research focused on the enhancement of evaporation of water droplets at sub-boiling temperatures on heated surfaces by the application of graphene nanoplatelets coatings.

• Dr Tong Wei Li
• Dr Ting Tiew Wei
• Dr Lim Elaine
• Dr Chang Fun Liang
• Dr Gan Jie Sheng
• Dr Lay Kok Keong
• Ng Ming Leong