Improved wettability of graphene nanoplatelets (GNP)/copper porous coatings for dramatic improvements in pool boiling heat transfer

Rishi, Aniket M.; Kandlikar, Satish G.; Gupta, Anju

doi:10.1016/j.ijheatmasstransfer.2018.11.169

Cited by 74 publications

(31 citation statements)

References 35 publications

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“…This was consistent for all the different weight ratios of GNP to copper particles. We established previously that the presence of hierarchical pores allows a continuous passage of bubbles and liquid via tunnel effect during the pool boiling process 30 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The effect of varying copper particle sizes during the ball milling was also investigated using three different copper particle sizes-1 µm, 20 µm, and 45 µm while keeping GNP concentration to 2 wt%. The 2 wt% GNP concentration was selected for all the coatings in this work based on our previous findings 30 . A detailed comparison of surface morphologies obtained with varying copper particle sizes, and the quantification of number of GNP layers for each is provided in the supporting information (see Supplementary Fig.…”

Section: Discussionmentioning

confidence: 99%

“…TESCAN Field Emission Mira III LMU (Czech Republic) and JSM-6400 V scanning electron microscope (SEM), JEOL, Ltd., Tokyo, Japan was used to observe the morphology and geometrical characteristics of pores of the sintered surfaces. The energy dispersive x-ray spectroscopy (EDS) analysis was performed on Bruker Quantax EDS with XFLASH 5010 detector attached to a field emission scanning electron microscope MIRA II LMH 30 . Transmission electron microscope JEOL 2010 in the range of 80 to 200 kV was used to observe the draping of GNP around copper particles.…”

Section: Methods Copper Surfacesmentioning

confidence: 99%

“…A multi-wavelength Jobin Yvon Horriba LabRAM HR Raman Spectroscope using He-Ne Laser (λ = 632.8 nm) was considered to quantify the deposited GNP layers and the acquisition time of 10 s was used to capture the data. To produce repeatable and reliable data, a total of 10 scans were taken by observing the characteristic D and G peaks of graphene 30 . Additionally, static wettability and dynamic wicking of sintered surfaces were measured for the surfaces using a VCA Optima Goniometer contact angle measurement instrument.…”

Section: Methods Copper Surfacesmentioning

confidence: 99%

“…We demonstrated this through electrodeposited graphene/copper based composite coatings possessing hierarchical porous network and highly wickable structures that yielded remarkable improvement in pool boiling 24 . Some of the noteworthy work performed in this field that have resulted in very high CHFs includes the use of micro/nanoscale coatings 25 – 27 , altering the heater surface wettability and wickability 28 – 30 , self-assembled structures with nanofluids as working fluids 31 , 32 .…”

Section: Introductionmentioning

confidence: 99%

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Salt templated and graphene nanoplatelets draped copper (GNP-draped-Cu) composites for dramatic improvements in pool boiling heat transfer

Rishi

Kandlikar

Gupta

2020

Sci Rep

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We demonstrate a novel technique to achieve highly surface active, functional, and tunable hierarchical porous coated surfaces with high wickability using a combination of ball milling, salttemplating, and sintering techniques. Specifically, using ball-milling to obtain graphene nanoplatelets (Gnp) draped copper particles followed by salt templated sintering to induce the strength and cohesiveness to the particles. The salt-templating method was specifically used to promote porosity on the coatings. A systematic study was conducted by varying size of the copper particles, ratio of Gnp to copper particles, and process parameters to generate a variety of microporous coatings possessing interconnected pores and tunnels that were observed using electron microscopy. pool boiling tests exhibited a very high critical heat flux of 289 W/cm 2 at a wall superheat of just 2.2 °C for the salt templated 3 wt% GNP draped 20 µm diameter copper particles with exceedingly high wicking rates compared to non-salt-templated sintered coatings. the dramatic improvement in the pool boiling performance occurring at a very low surface temperature due to tunable surface properties is highly desirable in heat transfer and many other engineering applications.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methods Copper Surfacesmentioning

confidence: 99%

Section: Methods Copper Surfacesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Salt templated and graphene nanoplatelets draped copper (GNP-draped-Cu) composites for dramatic improvements in pool boiling heat transfer

Rishi

Kandlikar

Gupta

2020

Sci Rep

Self Cite

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Effect of Ball Milled and Sintered Graphene Nanoplatelets–Copper Composite Coatings on Bubble Dynamics and Pool Boiling Heat Transfer

et al. 2020

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In this work, we present the efficacy of graphene nanoplatelets-copper (GNP-Cu) composite coatings formed by ball milling and sintering methods in enhancing pool boiling i.e. phase change heat transfer tested for distilled water. The pool boiling performance was quantified by an increase in critical heat flux (CHF) and heat transfer coefficient (HTC) at the lower wall superheat temperature. The ball milling facilitated draping of highly thermally conductive GNP around individual copper particles and subsequent sintering resulted in morphological features that further promoted high wicking rates of the coatings. A variety of coatings were formed with varying GNP Introduction:The distinctive structure of a single layered sp 2 -hybridized carbon atoms endows the thinnest material known as graphene, which has gained an enormous attention in various industrial applications such as surface coatings [1][2][3][4] , electronics [5,6] , energy storage [7,8] , lithium-ion batteries [9][10][11][12] , automotive [13,14] , and aerospace sector [15][16][17] due to its exceptional electrical, thermal, and mechanical properties [18] . Owing to very high thermal conductivity, graphene has also been implemented in thermal interface materials [19,20] , nanofluids [21] , and composite coatings [22][23][24] for heat transfer applications that require high heat flux dissipation [25][26][27][28][29] . Pool boiling heat transfer is a phase change cooling technique which dissipates higher heat fluxes by absorbing a large amount of latent heat while converting a liquid into a vapor and is quantified by the maximum heat flux that a surface can dissipate, known as critical heat flux (CHF), the condition at which the vapor bubbles merge laterally due to excessive bubble generation and form a vapor layer on the boiling surface.The heat transfer coefficient (HTC), defined as the ratio of heat flux ( " ) to wall superheat temperature (ΔT �� = T �� -T �� ), determines how effectively the heat is being removed from the surface.Pool boiling performance primarily depends on heater surface properties along with thermal conductivity of the heater surface which allows the efficient extraction of heat by delaying the vapor layer formation over the entire heater surface. This CHF condition can result in serious thermal damage to the heater surface. Thus, to increase the operational range and safety of the instruments, enhancing the pool boiling performance is essential. Wickability is the ability of surface to absorb/wick the liquid and is crucial for achieving high pool boiling performance as high wickabiltiy ensures a continuous supply of liquid to bubble nucleation sites. Researchers have demonstrated that highly wickable graphene coatings [30][31][32] are able to inhibit the vapor layer formation, thereby, providing a better solution to improve the operational limits of the system. Our recent works have focused on exploring the surface-active properties and thermal characteristics for

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High‐Performance Boiling Surfaces Enabled by an Electrode‐Transpose All‐Electrochemical Strategy

Chen,

Hu,

Zhang

et al. 2024

Advanced Science

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High‐performance boiling surfaces are in great demand for efficient cooling of high‐heat‐flux devices. Although various micro‐/nano‐structured surfaces have been engineered toward higher surface wettability and wickability for enhanced boiling, the design and fabrication of surface structures for realizing both high critical heat flux (CHF) and high heat transfer coefficient (HTC) remain a key challenge. Here, a novel “electrode‐transpose” all‐electrochemical strategy is proposed to create superhydrophilic microporous surfaces with higher dendrites and larger pores by simply adding an electrochemical etching step prior to the multiple electrochemical deposition steps. Enabled by the high nucleation density and high wicking capability, a high boiling performance is shown on such “etching‐then‐deposition” surfaces with simultaneously high CHF of 2,641 ± 10 kW m−2 and high HTC of 214 ± 6 kW (m2 K)−1, which are more than 2.5 and 4.3‐fold enhanced from those on smooth surfaces, respectively. A very stable morphology and boiling performance of such surfaces subject to consecutive tests are also shown. Using this strategy, such superhydrophilic microporous layers are fabricated on curved surfaces with larger areas, both on spheres and slender cylinders, and demonstrate excellent boiling performance in quenching tests. This facile, geometry‐adaptive, durable, and scalable strategy is very promising for making high‐performance boiling surfaces for large‐scale industrial applications.

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Improved wettability of graphene nanoplatelets (GNP)/copper porous coatings for dramatic improvements in pool boiling heat transfer

Cited by 74 publications

References 35 publications

Salt templated and graphene nanoplatelets draped copper (GNP-draped-Cu) composites for dramatic improvements in pool boiling heat transfer

Salt templated and graphene nanoplatelets draped copper (GNP-draped-Cu) composites for dramatic improvements in pool boiling heat transfer

Effect of Ball Milled and Sintered Graphene Nanoplatelets–Copper Composite Coatings on Bubble Dynamics and Pool Boiling Heat Transfer

High‐Performance Boiling Surfaces Enabled by an Electrode‐Transpose All‐Electrochemical Strategy

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