Flow boiling enhancement on a horizontal heater using carbon nanotube coatings

Singh, Navdeep; Sathyamurthy, V.; Peterson, W.C.; Arendt, Jonathan L.; Banerjee, Debjyoti

doi:10.1016/j.ijheatfluidflow.2009.11.002

Cited by 77 publications

(21 citation statements)

References 10 publications

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“…Despite this observed behavior, conventional nucleation theory suggests that cavities formed by nanoscale pores would require very large superheats to become active due to the inverse relationship between cavity radius and required activation superheat [59]. Therefore, the mechanism by which CNTs reduce the incipience superheat for capillary wicks may be attributed to: 1) an increase in the microscale thermal boundary layer as occurs in flow boiling [229], or 2) changes to the wetting characteristics of the existing microscale cavities in a manner that reduces the required superheat. For example, Li et al [214] proposed that a nanorod coating increases the stability of a microcavity vapor embryo during pool boiling by feeding it with vapor trapped in the nanoscale pores.…”

Section: Nanostructured Coatingsmentioning

confidence: 99%

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Weibel

Garimella

2013

Advances in Heat Transfer

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Owing to their high reliability, simplicity of manufacture, passive operation, and effective heat transport, flat heat pipes and vapor chambers are used extensively in the thermal management of electronic devices. The need for concurrent size, weight, and performance improvements in high-performance electronics systems, without resort to active liquid-cooling strategies, demands passive heat spreading technologies that can dissipate extremely high heat fluxes from small hot spots. In response to these daunting application-driven trends, a number of recent investigations have focused on the design, characterization, and fabrication of ultra-thin vapor chambers for proximate heat spreading away from these hot spots. The predominant transport mechanisms and operational limits have been found to be different under these conditions relative to conventional low-power heat pipes. Noteworthy advances in the fundamental understanding of evaporation and boiling from porous microstructures fed by capillary action, and improvements in vapor chamber characterization, modeling, design, and fabrication techniques are reviewed. Characterization of evaporation and boiling from idealized and realistic wick structures, observation of vapor formation regimes as a function of operating conditions, assessment of fluid dryout limitations, design of novel multi-scale and nanostructured wicks for enhanced transport, and incorporation of these high heat flux transport phenomena into device-level models are discussed. These recent developments have successfully extended the maximum operating heat flux limits of vapor chambers.2

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Section: Nanostructured Coatingsmentioning

confidence: 99%

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Weibel

Garimella

2013

Advances in Heat Transfer

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“…Nano/microscale coating [9,10,12,13,21] CHF+ DP+ and HTC$ Surface roughness [26,27] CHF+ and HTC+ DP+ * + increase; À decrease; $ little effect or unknown.…”

Section: Surface Modificationmentioning

confidence: 99%

“…For example, to suppress flow instability, inlet/outlet restrictors [4,5] and reentrant cavity [6,7] were introduced. Recently, nanofluid (e.g., Al 2 O 3 nanoparticle in DI-water [8]) and nano/microscale coating (e.g., nanowire [9][10][11], nanotube [12] and nanoporous surface [13]) were developed to improve wettability. Meanwhile, surfactant can enhance CHF by reducing surface tension of fluids [14].…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical studies of critical heat flux of flow boiling in microchannels with microbubble-excited high-frequency two-phase oscillations

Yang

Alam

et al. 2015

International Journal of Heat and Mass Transfer

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“…Convective heat transfer values were derived from the experiments by using the wall temperature gradient measurements that were obtained in these experiments. [38][39][40][61][62][63] In these studies, the nanoparticle material, concentration of the nanoparticles, duration of experimentation, flow rates and surface temperature were reported to affect the thermal performance of the nanofluids. …”

Section: Yu Et Almentioning

confidence: 99%

Numerical Investigation of the Effect of Chirality of Carbon Nanotube on the Interfacial Thermal Resistance

Hu¹

2013

J Nanofluids

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Concentrated Solar Power (CSP) systems are used widely as a stable and reliable renewable source of energy. However, intermittency of this power source and the variability in demand for electrical power creates challenges that necessitate the integration with energy storage for reliable dispatch of power. Thermal Energy Storage (TES) systems provide a cheap, cost-effective and reliable option for energy storage in renewable power delivery systems. Due to their low vapor pressures at elevated temperatures, molten salts and their eutectics are used in conventional high temperature thermal energy storage (TES) systems and also as coolants for energy conversion, such as in power tower configurations that are typically used in CSP applications. A major drawback of the molten salts is their relatively poor thermo-physical properties, which may lead to lower systemic efficiencies in CSP/TES. Recent reports in the literature have shown that doping molten salts with nanoparticles at minute concentrations (typically less than 5% mass fraction and ideally at less than 1-2% mass fraction) can significantly enhance the thermo-physical properties of these nanomaterial (also termed as "nanocomposites" in solid state and "nanofluids" in liquid state). The dominant factor that controls the resultant thermo-physical properties of these nanomaterials is the interfacial thermal resistance (or Kapitza Resistance "R k ") that impedes the heat transfer between the nanoparticle surface and the bulk solvent molecules.ii In this study, the interfacial thermal resistance between a carbon nanotube (CNT) and carbonate molten salt eutectics were calculated by using numerical models that were then implemented in Molecular Dynamics (MD) simulations. The estimates for "R k " obtained from these simulations enabled the prediction of the optimum dimensions of the nanoparticles for maximizing the thermo-physical properties of the mixture, i.e. thermal conductivity and specific heat capacity values of these nanomaterial. The simulations were restricted to the carbonate salt eutectic, which is composed of a molar ratio of 62:38 for lithium carbonate (Li 2 CO 3 ) and potassium carbonate (K 2 CO 3 ). In this study, parametric simulations were performed to estimate the values of "R k " by varying the chirality of a single walled CNT (i.e, for armchair, chiral, and zig-zag CNT). The results show that the Kapitza resistance of the CNT is significantly affected by the change in the chirality of the CNT.

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Flow boiling enhancement on a horizontal heater using carbon nanotube coatings

Cited by 77 publications

References 10 publications

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Experimental and theoretical studies of critical heat flux of flow boiling in microchannels with microbubble-excited high-frequency two-phase oscillations

Numerical Investigation of the Effect of Chirality of Carbon Nanotube on the Interfacial Thermal Resistance

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