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ABSTRACT
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 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 studied. 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.
Nomenclature
| C | = | constant in Eq. (Equation6 |
| cpL | = | liquid specific heat, J/kgK |
| cpbf | = | base fluid specific heat, J/kgK |
| cpnf | = | nanofluid specific heat, J/kgK |
| cpnp | = | nanoparticle specific heat, J/kgK |
| CA | = | contact angle |
| CHF | = | critical heat flux |
| CNT | = | carbon nanotube |
| D | = | tube diameter, m |
| Dbub | = | bubble departure diameter, m |
| DI | = | deionized |
| FCNT | = | functionalized carbon nanotube |
| G | = | mass flux, kg/m2s |
| GA | = | gum acacia |
| g | = | gravity constant, 9.81 m/s2 |
| hcb | = | convective heat transfer coefficient, W/m2K |
| hLV | = | latent heat of evaporation, J/kg |
| hnb | = | nucleate boiling heat transfer coefficient, W/m2K |
| kL | = | liquid thermal conductivity, W/mK |
| LH | = | heated length, m |
| M | = | molecular weight |
| MWCNT | = | multiwalled carbon nanotube |
| Nu | = | Nusselt number |
| PrL | = | liquid Prandtl number, defined by Eq. (Equation13 |
| Pout | = | outlet pressure, Pa |
| pr | = | reduced pressure |
| q | = | heat flux, W/m2 |
| q” | = | heat flux, W/m2 |
| qcrit | = | critical heat flux (CHF), W/m2 |
| Ra | = | surface roughness, µm |
| Rp | = | surface roughness, µm |
| ReDh | = | Reynolds number based on hydraulic diameter |
| ReL | = | liquid film Reynolds number, defined by Eq. (Equation12 |
| SDBS | = | Sodium dodecyl benzene sulphonate |
| SEM | = | scanning electron microscopy |
| SWCNT | = | single-walled carbon nanotube |
| Tin | = | temperature of the fluid at inlet, K |
| Tsat | = | saturation temperature of the fluid, K |
| Ts | = | saturation temperature of the fluid, K |
| Ttc,4 | = | wall temperature at location 4, K |
| TW | = | wall temperature, K |
| ul | = | liquid film velocity, m/s |
| WeL | = | Weber number based on heated length, defined by Eq. (Equation15 |
Greek symbols
| aL | = | liquid thermal diffusivity, m2/s |
| β | = | contact angle, |
| Δpsat | = | superheated pressure difference between the pressure at wall temperature and saturated fluid pressure, Pa |
| ΔTsat | = | superheated temperature difference between the wall temperature and saturated fluid temperature, K |
| δ | = | liquid film thickness, m |
| φ | = | volume fraction of spheres in the suspension |
| µf | = | viscosity of ambient fluid, N/m2s |
| µL | = | liquid dynamic viscosity, N/m2s |
| µmix | = | viscosity of the mixed fluid, N/m2s |
| θ | = | contact angle, ° |
| ρbf | = | base fluid density, kg/m3 |
| ρL | = | liquid density, kg/m3 |
| ρnf | = | nanofluid density, kg/m3 |
| ρnp | = | nanoparticle density, kg/m3 |
| ρV | = | vapor density, kg/m3 |
| σ | = | surface tension, N/m |
| τ | = | time, second |
Subscripts
| bf | = | base fluid |
| bub | = | bubble |
| cb | = | convective boiling |
| crit | = | critical |
| f | = | fluid |
| H | = | heated |
| in | = | inlet |
| L | = | liquid |
| LV | = | liquid–vapor |
| mix | = | mixture |
| nb | = | nucleate boiling |
| nf | = | nanofluid |
| np | = | nanoparticle |
| out | = | outlet |
| p | = | constant pressure |
| sat | = | saturation |
| s | = | saturation |
| tc | = | thermocouple |
| V | = | vapor |
| W | = | wall |
Additional information
Funding
Notes on contributors
Lixin Cheng
Lixin Cheng is a principal lecturer at Sheffield Hallam University, UK since 2016. He obtained his Ph.D. in Thermal Energy Engineering at the State Key Laboratory of Multiphase Flow of Xi'an Jiaotong University, China in 1998. He has extensive international working and collaboration experience as associate professor, senior lecturer, lecturer, and research fellow at Aarhus University, University of Portsmouth, University of Aberdeen, Swiss Federal Institute of Technology in Lausanne, Leibniz University of Hannover, London South Bank University, and Eindhoven University of Technology since 2000. He was awarded an Alexander von Humboldt Research Fellowship in 2004–2006. His research interests include multiphase flow and heat transfer, nanofluid flow and heat transfer, and heat exchangers. He has published more than 100 papers in journals and conferences, 10 book chapters, and edited 10 books.
Guodong Xia
Guodong Xia is a leading professor in Thermal Energy Engineering at Beijing University of Technology, China. He received his Ph.D. in Thermal Energy Engineering at the State Key Laboratory of Multiphase Flow of Xi'an Jiaotong University, China in 1996. He was a visiting professor in the Institute of Process Engineering at the University of Hanover, Germany in 2000–2001. His research interests include fundamentals and applications of microscale heat transfer, multiphase flow and heat transfer, waste energy recovery, thermal energy system, and heat exchangers. He is a member of the Chinese Society of Engineering Thermophysics and a member of the Multiphase Flow Committee of the Chinese Society of Theoretical and Applied Mechanics. He has published more than 100 papers in journals and design and enhanced heat transfer.
Qinling Li
Qinling Li is a senior lecturer in the Department of Engineering and Mathematics, Sheffield Hallam University. After receiving her Ph.D. in the School of Engineering & Science, University of Southampton, she worked as research associate in Aeronautical and Automatics Engineering Department, Loughborough University (2003–6), and the Department of Applied Mathematics and Theoretical Physics, University of Cambridge (2006–9). Her main research fields are fundamentals and applications of compressible turbulence, shock-waves boundary layer interaction, jet-in-cross flow & mixing, turbine/combustion chamber cooling effectiveness, fan broadband noise prediction, short take-off and vertical landing aircraft in descending phase, high-order numerical methods used in DNS/LES, fluid-structure interaction, and thermofluids including nanofluids and microscale fluid and heat transfer.
John R. Thome
John R. Thome is Professor and Director of the Laboratory of Heat and Mass Transfer (LTCM) at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland since 1998. He obtained his Ph.D. at Oxford University in 1978. His research interests cover two-phase flow and heat transfer, and a wide range of applications. He is the author of five books and has published over 230 journal papers since joining EPFL. He received the ASME Heat Transfer Division's Journal of Heat Transfer Best Paper Award in 1998, the United Kingdom's Institute of Refrigeration J.E. Hall Gold Medal in 2008, the 2010 ASME Heat Transfer Memorial Award, an ASME 75th Anniversary Medal from the Heat Transfer Division, the ICEPT-HDP 2012 Best Paper Award on a 3D-IC prototype with interlayer cooling, the ASME Journal of Electronics Packing Best Paper Award at IMECE in November 2014, and most recently the prestigious 2016 Nusselt–Reynolds Prize.