Experimental analysis for heat transfer of nanofluid with wire coil turbulators in a concentric tube heat exchanger

Akyürek, Eda Feyza; Geliş, Kadir; Şahin, Bayram; Manay, Eyüphan

doi:10.1016/j.rinp.2018.02.067

Cited by 96 publications

(22 citation statements)

References 23 publications

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“…The isobaric specific heat for nanofluids is expected to decrease with respect to the base fluid because the isobaric specific heat of fluids is usually higher than that of solids, although some experimental results have shown the opposite behaviour. 4,49 In our case, C P decreased by about 1.6% with respect to the base fluid, but this variation is of the same order as the uncertainty of the measurements. with temperature, which means they followed the opposite trend to the base fluid.…”

Section: Nanofluid Performancementioning

confidence: 45%

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Martínez-Merino

Midgley

Martín

et al. 2020

ACS Appl. Mater. Interfaces

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Nano-colloidal suspensions of nanomaterials in a fluid, nanofluids, are appealing because of their interesting properties related to heat transfer processes. Whilst nanomaterials based on transition metal chalcogenides (TMCs) have been widely studied in catalysis, sensing, and energy storage applications, there are few studies of nanofluids based on TMCs for heat transfer applications. In this study, the preparation and analysis of nanofluids based on 2D-WS 2 in a typical heat transfer fluid (HTF) used in concentrating solar power (CSP) plants is reported. Nanofluids prepared using an exfoliation process exhibited well-defined nanosheets and were highly stable. The nanofluids were characterized in terms of properties related to their application in CSP. The presence of WS 2 nanosheets did not modify significantly the surface tension, the viscosity, or the isobaric specific heat, but the thermal conductivity was improved by up to 30%. The U r factor, which characterizes the thermal efficiency of the fluid in the solar collector, shows an enhancement of up to 22% in the nanofluid, demonstrating great promise for CSP applications. The Reynolds number and friction factor of the fluid were not significantly modified by the addition of the nanomaterial to the HTF, which is also positive for practical applications in CSP plants. Ab initio molecular dynamics simulations of the nanoparticle/fluid interface showed an irreversible dissociative adsorption of diphenyl oxide molecules on the WS 2 edge, with very low kinetic barrier. The resulting 'decoration' of the WS 2 edge dramatically affects the nature of the interface interactions and is therefore expected to affect significantly the rheological and transport properties of the nanofluids.

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Section: Nanofluid Performancementioning

confidence: 45%

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Martínez-Merino

Midgley

Martín

et al. 2020

ACS Appl. Mater. Interfaces

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“…No que tange ao momento atual do desenvolvimento da tecnologia dos processos de transferência de calor, uma importante área de pesquisa e desenvolvimento refere-se à aplicação de nanofluidos como fluidos de troca térmica dentro de trocadores de calor do tipo casco-tubo como apresentado por Choi et al, (2011), Saeedinia et al, (2012), Azad e Azad (2016), Han et al, (2017), Akyürek et al, (2018).…”

Section: Motivaçãounclassified

Síntese e caracterização de nanofluidos para aplicação em sistemas térmicos

Oliveira¹

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iii À minha mãe Regina, exemplo de vida, força, fé e amor.Ao meu esposo Elias, companheiro, amigo e motivador de todas as minhas conquistas.E, ao progresso da ciência! iv "Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less." Marie Curie v AGRADECIMENTOSAgradeço à Deus por sempre guiar o meu caminho.À minha família pela educação e por toda a sua contribuição para o meu crescimento.Ao Prof. Dr. Enio Pedone Bandarra Filho pela confiança em mim depositada, acolhimento, oportunidade e orientação desta Tese. AbstractThe goals of this work were to study the synthesis and characterization of the thermophysical properties of various types of nanofluids in order to evaluate their application in thermal exchange systems. For this, nanofluids of aqueous base, base oil and ethylene glycol base were prepared and studied, containing six types of nanoparticles: TiO2, Ag, Cu, MWCNT, diamond and graphene. Hybrid nanoparticles (Diamond-Nickel, MWCNT-Ag, graphene-Ag) and functionalized surface MWCNT-COOH, Di-COOH and TiO2-PVA were also produced. For the structural characterization of the nanoparticles, X-ray diffraction (XRD), Raman spectroscopy and infrared (FTIR) techniques were used, as well as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images. The synthesis of the nanofluids consisted of the application of the "two-step" method, using sonication processes and high pressure homogenization to disperse the nanoparticles, using volumetric concentrations ranging from 0.00125% to 0.1%, and mass concentrations of 0.05 to 1.0 wt%, in base fluids. The thermophysical properties (thermal conductivity and viscosity) were measured experimentally in a temperature range of 10° to 60° C and an increase in both the thermal conductivity and the viscosity were observed with the increase in the volumetric fraction of nanoparticles and with the temperature. The stability of the nanofluids was evaluated by the sedimentation observation method. In general, nanofluids without stabilizers remained stable for a few weeks. The experimental results, obtained for thermal conductivity, revealed a maximum increase of 10.67% for diamond nanofluids in mineral oil with oleic acid as stabilizing agent. The maximum increase in viscosity was obtained for nanofluidos of MWCNT, being 1.6 times greater than the viscosity of the water. The results, of thermal conductivity, viscosity and specific mass, were still compared with the classic models of the literature. Thus, the studies of the synthesis and characterization of nanofluids revealed an increase of the thermal conductivity with the dispersion of nanoparticles being a promising alternative as fluids applied in processes of thermal changes.

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“…According to the above description and also by referring to previous researches in this field of research, due to the complexity of the target functions and the number of optimization variables, to optimize the design of the DPHE and fluid flow conditions by minimizing entropy generation, GA optimization method is used in this study. Considering the reliable previous investigations around DPHEs with helical coil inserts [45,52,53], a wide range of the decision parameters are selected for the optimization process. The details of the optimization process are expressed as the following equations: Figure 2 shows the detailed flowchart of the GA optimization procedure and algorithm of computation for the optimum selection of the system.…”

Section: Optimization Processmentioning

confidence: 99%

A comprehensive thermo-hydraulic analysis and optimization of turbulent TiO2/W-EG nano-fluid flow inside double-pipe heat exchangers with helical coil inserts

Ebrahimi‐Moghadam

Gohari

Hoseinzade

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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The main aim in current work is to optimize TiO 2 /W-EG nano-fluid (with 60 vol% of water and 40 vol% of ethylene glycol) flow within the inner tube of the double-pipe heat exchangers with helical coil inserts. The entropy generation is selected as the target function and is to be minimized. To reach this goal, at the first step, a comprehensive sensitivity analysis is carried out taking into account all of the nano-fluid flow conditions (including nanoparticle volume fraction , Reynolds number Re and Prandtl number Pr) and geometric parameters of the helical coil inserts (including thepitch-to-diameter ratio of coil Π). Afterward, the genetic algorithm (GA) is utilized in the optimization process. The results of sensitivity analysis reveal that and Π , respectively, have the highest and lowest impact on the thermodynamics characteristics. Also, the addition of up to 0.02 vol% nanoparticles leads to a maximum of 13.93% improvement in dimensionless entropy generation (DEG). The outputs of the GA are opt = 0.0198%, Re opt = 8421.173, Pr opt = 32.833, Π opt = 2.437 and DEG opt = 0.005086. Furthermore, based on the optimization results, a useful correlation is proposed to find the optimum geometry of the helical coil based on the nano-fluid flow conditions.

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Experimental analysis for heat transfer of nanofluid with wire coil turbulators in a concentric tube heat exchanger

Cited by 96 publications

References 23 publications

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Síntese e caracterização de nanofluidos para aplicação em sistemas térmicos

A comprehensive thermo-hydraulic analysis and optimization of turbulent TiO2/W-EG nano-fluid flow inside double-pipe heat exchangers with helical coil inserts

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Experimental analysis for heat transfer of nanofluid with wire coil turbulators in a concentric tube heat exchanger

Cited by 96 publications

References 23 publications

Novel WS2-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Novel WS2-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Síntese e caracterização de nanofluidos para aplicação em sistemas térmicos

A comprehensive thermo-hydraulic analysis and optimization of turbulent TiO2/W-EG nano-fluid flow inside double-pipe heat exchangers with helical coil inserts

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Product

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About

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights

Novel WS₂-Based Nanofluids for Concentrating Solar Power: Performance Characterization and Molecular-Level Insights