Experimental Convection Heat Transfer Analysis of a Nano-Enhanced Industrial Coolant

Álvarez-Regueiro, E.; Vallejo, Javier P.; Fernández-Seara, José; Fernández, Juan Manuel Vilar; Lugo, Luis

doi:10.3390/nano9020267

Cited by 19 publications

(8 citation statements)

References 52 publications

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“…The number of potential ILs is huge, due to the virtually uncountable combinations of different types of anions and cations, resulting in a formidable ability of dedicated fluid tailoring and design through the addition of different functional groups or variation in the cation alkyl-chain length [5]. ILs have very remarkable thermophysical, phase equilibria, and transport properties, and this includes virtually negligible vapor pressure, high thermal stability, tunable viscosity, and enhanced extraction capacity for diverse organic compounds and metals [6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Graphene IoNanofluids, Thermal and Structural Characterization

et al. 2019

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Graphene is considered a promising substance in applications related to the capture and reduction of the environmental impact of fluorinated gases. However, further research is still required to explore all related possibilities. In this work, the potential use in this context of nanofluids (NFs), obtained by dispersing graphene nanosheets in fluorinated ionic liquids (FILs) is investigated. As a starting step, a thermal and structural characterization for this type of IoNanofluids (IoNFs) is presented. The highly nanostructured nature of FILs has been recently demonstrated. The presence of fluorinated moieties is responsible for enhancing the accommodation of solutes such as small gases. The strong tendency to self-assemble forming continuous and supramolecular structures, and the versatility to rearrange in several conformational features allows the stabilization of nano colloidal systems. It is essential to perform a comprehensive study of their structural features to understand the behavior of this type of heterogeneous systems. Therefore, we present screening on the phase and structural behavior of these novel IoNFs to discover and develop optimized systems where FILs turn out to be advantageous. Thermogravimetric analysis (TGA) was employed to evaluate IoNFs mass losses with temperature, and their solid–fluid phase transitions were located using a differential scanning calorimeter (DSC). Their rheological properties were also determined through oscillatory experiments, obtaining the viscous and loss moduli. In addition, the structural percolation transition was also identified.

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Section: Introductionmentioning

confidence: 99%

Graphene IoNanofluids, Thermal and Structural Characterization

et al. 2019

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“…The inner tube presents an internal diameter, d 1 , of 0.008 m, and an external diameter, d 2 , of 0.010 m, while the outer tube has an internal diameter, d 3 , of 0.015 m. Meanwhile, the heat exchanger’s effective lengths are 0.93 m for heat exchange, L h , and 1.18 m for pressure drop, L Δ P . In previous works, detailed descriptions of the mentioned test rig have been reported [ 29 , 51 , 52 ].…”

Section: Methodsmentioning

confidence: 99%

“…The most common materials used as nanoadditives are carbon allotropes, metals, metal oxides, carbides or nitrides [ 12 , 13 , 14 , 15 , 16 ]. Regarding base fluids, different heat transfer fluids such as water [ 17 , 18 , 19 ], ethylene glycol [ 20 , 21 , 22 ], mixtures of the two [ 23 , 24 , 25 ], propylene glycol [ 26 ], engine oils or refrigerants have been commonly selected [ 27 , 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Heat Transfer Characteristics of a GnP Aqueous Nanofluid through a Double-Tube Heat Exchanger

et al. 2021

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The thermal properties of graphene have proved to be exceptional and are partly maintained in its multi-layered form, graphene nanoplatelets (GnP). Since these carbon-based nanostructures are hydrophobic, functionalization is needed in order to assess their long-term stability in aqueous suspensions. In this study, the convective heat transfer performance of a polycarboxylate chemically modified GnP dispersion in water at 0.50 wt% is experimentally analyzed. After designing the nanofluid, dynamic viscosity, thermal conductivity, isobaric heat capacity and density are measured using rotational rheometry, the transient hot-wire technique, differential scanning calorimetry and vibrating U-tube methods, respectively, in a wide temperature range. The whole analysis of thermophysical and rheological properties is validated by two laboratories. Afterward, an experimental facility is used to evaluate the heat transfer performance in a turbulent regime. Convective heat transfer coefficients are obtained using the thermal resistances method, reaching enhancements for the nanofluid of up to 13%. The reported improvements are achieved without clear enhancements in the nanofluid thermal conductivity. Finally, dimensionless analyses are carried out by employing the Nusselt and Péclet numbers and Darcy friction factor.

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“…Furthermore, the high solid volume fraction of nanoparticles (high dynamic viscosity) and fluid velocity manage highpressure drop and pumping power requirements. Thus, the overall system efficiency should be optimized to achieve high heat transfer with minimum power requirements [87]. The early transition from laminar to turbulent flow for NFs can ensure fluid turbulence under lower Re, without penalty on heat transfer and pressure drop [88].…”

Section: Heat Exchangersmentioning

confidence: 99%

Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

Fernandes

Gomes

Simões

et al. 2021

Chemical Engineering Journal

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Biofouling is the unwanted accumulation of deposits on surfaces, composed by organic and inorganic particles and (micro)organisms. Its occurrence in industrial equipment is responsible for several drawbacks related to operation and maintenance costs, reduction of process safety and product quality, and putative outbreaks of pathogens. The understanding on the role of operating conditions in biofouling development highlights the hydrodynamic conditions as key parameter. In general, (bio)fouling occurs in a higher extension when laminar flow conditions are used. However, the characteristics and resilience of biofouling are highly dependent on the hydrodynamic conditions under which it is developed, with turbulent conditions being associated to recalcitrant biodeposits. In industrial settings like heat exchangers, fluid distribution networks and stirred tanks, hydrodynamics plays a dual function, affecting the process effectiveness while favouring biofouling formation. This review summarizes the hydrodynamics played in conventional industrial settings and provides an overview on the relevance of hydrodynamic conditions in biofouling development as well as in the effectiveness of industrial processes.

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Experimental Convection Heat Transfer Analysis of a Nano-Enhanced Industrial Coolant

Cited by 19 publications

References 52 publications

Graphene IoNanofluids, Thermal and Structural Characterization

Graphene IoNanofluids, Thermal and Structural Characterization

Analysis of Heat Transfer Characteristics of a GnP Aqueous Nanofluid through a Double-Tube Heat Exchanger

Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

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