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Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review.

Kim H - Nanoscale Res Lett (2011)

Bottom Line: The purpose of this article is to provide an exhaustive review of these studies.Also, attempts to explain the physical mechanism based on available CHF theories are described.Finally, future research needs are identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Engineering, Kyung Hee University, Yongin, Gyunggi 446-701, Republic of Korea. hdkims@khu.ac.kr.

ABSTRACT
Nanofluids (suspensions of nanometer-sized particles in base fluids) have recently been shown to have nucleate boiling critical heat flux (CHF) far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also, attempts to explain the physical mechanism based on available CHF theories are described. Finally, future research needs are identified.

No MeSH data available.


Related in: MedlinePlus

Effect of nanoparticle layer in alumina-water nanofluids. (a) [53]; (b) [28].
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Figure 9: Effect of nanoparticle layer in alumina-water nanofluids. (a) [53]; (b) [28].

Mentions: The above-described two effects of nanoparticles (i.e., modification of the heater surface and structural disjoining pressure) both seem to be plausible hypotheses for CHF enhancement in nanofluids. However, to understand the principle mechanism of the phenomena, it is necessary to examine the single contribution of each factor to the enhanced CHF performance of nanofluids. Kim et al. [52,53] carried out an insightful experiment to separate the single effect of the nanoparticle deposition layer on the CHF of nanofluids. First, they conducted a pool-boiling test of a nanofluid using a fresh heater wire. A subsequent surface inspection confirmed the presence of a nanoparticle deposition layer on the heater wire. They then performed an additional CHF test on the nanoparticle-deposited wire submerged in pure water, which resulted in a CHF enhancement of the same magnitude as that of the nanofluids. The experimental results clearly demonstrated that the enhancement of CHF in nanofluids is due to the modification of surface topology associated with nanoparticle deposition on the heater surface during nanofluid boiling. Moreover, Golubovic et al. [19] and Kwark et al. [28] recently conducted the same experiments using both thin wire and flat-plate heaters and obtained experimental results consistent with those of Kim et al. [52,53]. Figure 9 shows the experimental results obtained by Kim et al. [53] and Kwark et al. [28].


Enhancement of critical heat flux in nucleate boiling of nanofluids: a state-of-art review.

Kim H - Nanoscale Res Lett (2011)

Effect of nanoparticle layer in alumina-water nanofluids. (a) [53]; (b) [28].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211511&req=5

Figure 9: Effect of nanoparticle layer in alumina-water nanofluids. (a) [53]; (b) [28].
Mentions: The above-described two effects of nanoparticles (i.e., modification of the heater surface and structural disjoining pressure) both seem to be plausible hypotheses for CHF enhancement in nanofluids. However, to understand the principle mechanism of the phenomena, it is necessary to examine the single contribution of each factor to the enhanced CHF performance of nanofluids. Kim et al. [52,53] carried out an insightful experiment to separate the single effect of the nanoparticle deposition layer on the CHF of nanofluids. First, they conducted a pool-boiling test of a nanofluid using a fresh heater wire. A subsequent surface inspection confirmed the presence of a nanoparticle deposition layer on the heater wire. They then performed an additional CHF test on the nanoparticle-deposited wire submerged in pure water, which resulted in a CHF enhancement of the same magnitude as that of the nanofluids. The experimental results clearly demonstrated that the enhancement of CHF in nanofluids is due to the modification of surface topology associated with nanoparticle deposition on the heater surface during nanofluid boiling. Moreover, Golubovic et al. [19] and Kwark et al. [28] recently conducted the same experiments using both thin wire and flat-plate heaters and obtained experimental results consistent with those of Kim et al. [52,53]. Figure 9 shows the experimental results obtained by Kim et al. [53] and Kwark et al. [28].

Bottom Line: The purpose of this article is to provide an exhaustive review of these studies.Also, attempts to explain the physical mechanism based on available CHF theories are described.Finally, future research needs are identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear Engineering, Kyung Hee University, Yongin, Gyunggi 446-701, Republic of Korea. hdkims@khu.ac.kr.

ABSTRACT
Nanofluids (suspensions of nanometer-sized particles in base fluids) have recently been shown to have nucleate boiling critical heat flux (CHF) far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also, attempts to explain the physical mechanism based on available CHF theories are described. Finally, future research needs are identified.

No MeSH data available.


Related in: MedlinePlus