The Effect of Micro/Nanoscale Structures on CHF Enhancement

Ahn, Ho Seon; Kim, Moo Hwan

doi:10.5516/net.2011.43.3.205

Cited by 13 publications

(7 citation statements)

References 24 publications

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“…Several studies on CHF with various nanofluids under different test conditions have been conducted in various channels. These covers the low pressure and low flow conditions [128,129], the effect of micro/nanoscale structures on CHF [130], flow boiling in downward-facing channels [131], CHF with magnetic nanofluids [132] and magnetic field effect on CHF with ferrofluid in annulus [133]. In general, CHF enhancement has been achieved but understanding the mechanisms is quite different and this needs to be further In recent years, several studies were conducted to investigate the flow boiling heat transfer and CHF behaviors with nanofluids in mini-and micro-channels [134][135][136][137][138][139][140][141][142].…”

Section: Research On Chf and Physical Mechanisms In Flow Boiling Withmentioning

confidence: 99%

Fundamental Issues, Technology Development, and Challenges of Boiling Heat Transfer, Critical Heat Flux, and Two-Phase Flow Phenomena with Nanofluids

Cheng

Thome

2018

Heat Transfer Engineering

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This paper presents a comprehensive and critical review of studies on nucleate pool boiling heat transfer, flow boiling heat transfer, critical heat flux (CHF) and two-phase flow phenomena with nanofluids. First, general analysis of the available studies on the relevant topics is presented. Then, studies of physical properties of nanofluids are discussed. Next, boiling heat transfer, CHF phenomena and the relevant physical mechanisms are explored. Finally, future research needs have been 2 identified according to the review and analysis. As the first priority, the physical properties of nanofluids have a significant effect on the boiling and CHF characteristics but the lack of the accurate knowledge of the physical properties has greatly limited the studies. Fundamentals of boiling heat transfer and CHF phenomena with Nanofluids have not yet been well understood. Flow regimes are important in understanding the boiling and CHF phenomena and should be focused on. Two phase pressure drops of nanofluids should also be studies. Furthermore, economic evaluation of the enhancement technology with nanofluid should be considered for the new heat transfer enhancement technology with nanofluids. Finally, applied research should be targeted to achieve an enabling practical heat transfer and CHF enhancement technology for engineering application with nanofluids.

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Section: Research On Chf and Physical Mechanisms In Flow Boiling Withmentioning

confidence: 99%

Fundamental Issues, Technology Development, and Challenges of Boiling Heat Transfer, Critical Heat Flux, and Two-Phase Flow Phenomena with Nanofluids

Cheng

Thome

2018

Heat Transfer Engineering

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“…Several studies on CHF with various nanofluids under different test conditions have been conducted in various channels. These covers the low pressure and low flow conditions, the effect of micro/nanoscale structures on CHF, flow boiling in downward-facing channels, CHF with magnetic nanofluids and magnetic field effect on CHF with ferrofluid in annulus [58][59][60][61][62]. In general, CHF enhancement has been achieved but understanding the mechanisms is quite different and this needs to be further investigated.…”

Section: Flow Boiling Heat Transfer and Chf With Nanofluids In Macrosmentioning

confidence: 99%

Two Phase Flow and Thermal Physics of Nanofluids: Understanding the Fundamentals, Mechanisms and Challenges

Cheng¹

2018

Proceedings of the 3rd World Congress on Momentum, Heat and Mass Transfer

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This keynote lecture presents a comprehensive review of the state-of-the-art research on nanofluid two phase flow and thermal physics. First, studies of the physical properties of nanofluids are summarized. Then, analysis of the available experimental studies on nucleate boiling and critical heat flux (CHF) is presented. Next, flow boiling and two phase flow of nanofluid in macroscale and microscale channels are discussed. Finally, analysis and discussion of the existing correlations and models with the relevant physical properties are presented. According to this comprehensive review, future research needs have been identified. So far, fundamentals of boiling heat transfer and CHF phenomena of nanofluids have not yet been well understood. Therefore, systematic accurate experiments and flow regime observations of boiling heat transfer and CHF phenomena with various types of nanofluids under a wide range of test conditions should be emphasized. Furthermore, physical mechanisms, theory and prediction methods for boiling heat transfer, two phase flow and CHF characteristics should be targeted at in the future. Practical application of nanofluid two phase flow and heat transfer should also be considered.

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“…Yüzeyde biriken ince nanopartikül tabakası kanal yüzeyinin ıslatılabilirliğini değiştirir. Nanopartiküller statik temas açısının azalmasına yol açarak yüzeyin ıslatılabilirliğini arttırmışlardır (Ahn and Kim, 2011). Nanopartikül ilavesiyle yüzey pürüzlülüğündeki ve adezyon kuvvetindeki artış yüzey ıslatılabilirliğini arttırmıştır (Kandlikar et al, 2014).…”

Section: Mikrokanallarda Nanoakışkanların Kaynamalı Akış Karakteristiunclassified

Section: Buunclassified

Flow Boiling Characteristics of Nanofluids in Microchannels

Manay¹

2017

jist

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ÖZET: Mikrocihazlarda giderek artan ısı akısı değerleri nedeniyle geleneksel ısı transfer arttırım yöntemleri mikrosistemlerin soğutulmasında yetersiz kalmaktadır. Kaynama ile ısı transferi yüksek ısı transfer katsayılarının elde edilmesi yanında yüzey sıcaklığının neredeyse sabit olması nedeniyle yüksek ısı atımını gerektiren mikrosistem uygulamaları için önemli bir potansiyele sahiptir. Diğer yandan geleneksel akışkanlar yerine nanoakışkanların kullanımı yüksek ısıl performans için önemli bir alternatif olarak düşünülmektedir. Nanoakışkanların tek fazlı ısı transferiyle ilgili birçok çalışma olmasına rağmen mikrokanallarda kaynamalı akış durumunda nanoakışkan kullanımıyla ilgili sınırlı sayıda çalışma mevcuttur. Literatürde nanoakışkanların kaynamalı akışta kullanımının bazı çalışmalara göre uygun olup olmadığı yönünde belirsizlikler vardır. Bu nedenle nanoakışkanların kaynamalı akış şartlarında kullanılabilirliği ile ilgili daha kapsamlı çalışmalara ihtiyaç vardır. Bu çalışmada, farklı nanoakışkanlar ile yapılan deneysel çalışmalar derlenmiş ve nanoakışkanların mikrokanallarda kaynamalı akışta kullanımının avantaj ve dezavantajları belirlenmeye çalışılmıştır.Anahtar kelimeler: Kaynamalı akış, kritik ısı akısı, mikrokanal, nanoakışkan ABSTRACT: Due to the ever increasing heat flux values, traditional heat transfer enhancement methods fail to satisfy on cooling of micro systems. Flow boiling heat transfer has a great potential for the applications requiring high heat removal rates because high heat transfer coefficients are achieved in addition to surface temperature to be nearly constant. On the other hand, use of nanofluids instead of traditional fluids is thought to be an important alternative for high thermal performance. Although there are numerous study on the single phase heat transfer of nanofluids, a few number of study concerning with the flow boiling heat transfer of nanofluids in microchannels exists. In the literature, there are some conflicts on whether the use of nanofluids in flow boiling is appropriate or not. Thus, more detailed studies on the usability of nanofluids in boiling flow conditions are required. In this study, experimental studies conducted by with nanofluids were reviewed, and the advantages and disadvantages of the using nanofluids in boiling flows in microchannels were determined.

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The Effect of Micro/Nanoscale Structures on CHF Enhancement

Cited by 13 publications

References 24 publications

Fundamental Issues, Technology Development, and Challenges of Boiling Heat Transfer, Critical Heat Flux, and Two-Phase Flow Phenomena with Nanofluids

Fundamental Issues, Technology Development, and Challenges of Boiling Heat Transfer, Critical Heat Flux, and Two-Phase Flow Phenomena with Nanofluids

Two Phase Flow and Thermal Physics of Nanofluids: Understanding the Fundamentals, Mechanisms and Challenges

Flow Boiling Characteristics of Nanofluids in Microchannels

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