Mixed convection in a rotating eccentric annulus containing nanofluid using bi-orthogonal grid types: A finite volume simulation

Teimouri, Hamid; Sheikhzadeh, Ghanbar Ali; Afrand, Masoud; Fakhari, Mohammad Mahdi

doi:10.1016/j.molliq.2016.11.094

Cited by 17 publications

(6 citation statements)

References 41 publications

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“…Fig. 31 reflects the exergy efficiency of enhanced tube with turbulators based on equation (16). Through theoretical analysis, it is easy to find that the entire coordinate system is divided into four regions (Ⅰ, Ⅱ, Ⅲ, Ⅳ) by three boundary lines.…”

Section: Exergy Efficiency Evaluationmentioning

confidence: 99%

“…These consequences revealed that the heat transfer characteristics increase with the rising Darcy number in the non-porous region but decrease in the porous region. Teimouri et al [16] explored the numerical simulation of laminar mixed convection in horizontal eccentric annulus. The consequences showed that Nu numbers augment with the rising of downward eccentricity of inner cylinder.…”

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confidence: 99%

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Effects of turbulator with round hole on the thermo-hydraulic performance of nanofluids in a triangle tube

Fan

Pan

et al. 2020

International Journal of Heat and Mass Transfer

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For investigating the thermal and hydraulic characteristics of water-based SiO 2 nanofluids in a triangular tube with different turbulators, an experimental system has been designed and verified in this paper. The effects of different round hole diameters (d=3mm, 4mm, 5mm) and round hole pitch-rows (l=5cm, 10cm, 15cm) of perforated turbulators on the thermo-hydraulic characteristics are researched.Meanwhile, the influences of Reynolds numbers (Re=400-8000) and nanoparticles mass fractions (D-I water, ω=0.1%, 0.3%, 0.5%) are also studied. These experimental results show that, under the same circumstance, the nanofluids in the triangular tube with ω=0.5% have the largest positive influence on the heat transfer enhancement ratio which is up to 16.73%. For a comprehensive study of the flow and heat transfer, thermal efficiency (comprehensive performance index) and exergy efficiency are adopted. It can be found that the larger the diameter and the smaller the pitch-row of the holes is, the greater the comprehensive evaluation index can be. In addition, all working conditions exhibit the superior exergy efficiency. The highest exergy efficiency can be got when Re=6000 and ω=0.5%.

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Section: Exergy Efficiency Evaluationmentioning

confidence: 99%

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confidence: 99%

Effects of turbulator with round hole on the thermo-hydraulic performance of nanofluids in a triangle tube

Fan

Pan

et al. 2020

International Journal of Heat and Mass Transfer

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“…On the other hand, Table 2 presents a comprehensive review of fluid flow and heat transfer in Taylor-Couette-Poiseuille flow, where the axial flow is encountered in such applications. The listed work is ordered from recent to early papers within three categories, namely fluid flow work, [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] forced convection heat transfer work for concentric, 1,[40][41][42][43][44][45][46][47][48] and eccentric [49][50][51][52][53][54][55][56][57][58] annuli. The fluid flow work, reported in Table 2, indicated that the topic receives a major consideration in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…Most of the reported work on forced convection heat transfer in eccentric annuli (Table 2) is conducted for stationary inner cylinder [51][52][53][54][55][56][57][58] under a wide range of eccentricity (0-1) and laminar and turbulent flow conditions. Only the work presented in 49,50 was performed under rotational conditions for a very narrow annulus with a radius ratio of 0.928 and an eccentricity of 0.928 49 or for a fixed annulus with a radius ratio of 0.333 and eccentricity ranges from 0 to 0.4.…”

Section: Introductionmentioning

confidence: 99%

Fluid flow and convection heat transfer in concentric and eccentric cylindrical annuli of different radii ratios for Taylor-Couette-Poiseuille flow

Abou-Ziyan

Ameen

Elsayed

2021

Advances in Mechanical Engineering

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This paper presents the results of fluid flow and convection heat transfer in concentric and eccentric annuli between two cylinders using a three-dimensional computational fluid dynamics model. Effects of rotational speed ( n = 0, 150, 300, and 400 rpm) and eccentricity (ε = 0, 0.15, 0.3, 0.45, and 0.6) on axial and tangential velocity distribution, pressure drop and forced convection heat transfer are investigated for radii ratios (η) of 0.2, 0.4, 0.6, and 0.8, Reynolds number 2.0 × 103–1.236 × 105, Taylor number 1.47 × 106–1.6 × 1010, and Prandtl number 3.71–6.94. The parameters cover many applications, including rotary heat exchangers, mixers, agitators, etc. Nusselt numbers and friction factors for stationary and rotated concentric and eccentric annuli are correlated with four dimensionless numbers. The results revealed that when the speed of the inner cylinder increases from 0 to 400 rpm, the friction factor increases by 7.7%–103% for concentric and 8.2%–148% for eccentric annuli, whereas Nusselt number enhances by 37%–333% for concentric and 44%–340% for eccentric annuli. The radius ratio has a substantial effect on the heat transfer and pressure drop in annuli. The eccentricity enhances the heat transfer up to 12%, whereas its effect on the friction factor is not monotonic as it depends on Reynolds number, radii ratios, and rotational speed.

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“…This study introduced new correlations of the Nusselt number as a function of Grashof number, Prandtl number and nanoparticle volume fraction. By using the finite volume method and SIMPLER algorithm, Teimouri et al (2017) dealt with the laminar mixed convection of nanofluid flow in an eccentric annulus in the cases of different parameters such as eccentricity, the volume fraction of nanoparticles. Izadi et al (2013a) numerically solved the laminar mixed convection of Al 2 O 3 -water nanofluid flow to investigate the influences of the Richardson number on the friction coefficient and the heat transfer coefficient in a concentric cylinder.…”

Section: Introductionmentioning

confidence: 99%

Entropy generation of mixed convection of SWCNT–water nanofluid filled an annulus with a rotating cylinder and porous lining under LTNE

Çiçek

Baytaş

2020

HFF

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Purpose The purpose of this study is to numerically analyze the mixed convection and entropy generation in an annulus with a rotating heated inner cylinder for single-wall carbon nanotube (SWCNT)–water nanofluid flow using local thermal nonequilibrium (LTNE) model. An examination of the system behavior is presented considering the heat-generating solid phase inside the porous layer partly filled at the inner surface of the outer cylinder. Design/methodology/approach The discretized governing equations for nanofluid and porous layer by means of the finite volume method are solved by using the SIMPLE algorithm. Findings It is found that the buoyancy force and rotational effect have an important impact on the change of the strength of streamlines and isotherms for nanofluid flow. The minimum average Nusselt number on the inner cylinder is obtained at Ra$_E$ = 10$^4$, and the minimum total entropy generation is found at Re = 400 for given parameters. The entropy generation minimization is determined in case of different nanoparticle volume fractions. It is observed that at the same external Rayleigh numbers, the LTNE condition obtained with internal heat generation is very different from that without heat generation. Originality/value To the best of the authors’ knowledge, there is no previous paper presenting mixed convection and entropy generation of SWCNT–water nanofluid in a porous annulus under LTNE condition. The addition of nanoparticles to based fluid leads to a decrease in the value of minimum total entropy generation. Thus, using nanofluid has a significant role in the thermal design and optimization of heat transfer applications.

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Mixed convection in a rotating eccentric annulus containing nanofluid using bi-orthogonal grid types: A finite volume simulation

Cited by 17 publications

References 41 publications

Effects of turbulator with round hole on the thermo-hydraulic performance of nanofluids in a triangle tube

Effects of turbulator with round hole on the thermo-hydraulic performance of nanofluids in a triangle tube

Fluid flow and convection heat transfer in concentric and eccentric cylindrical annuli of different radii ratios for Taylor-Couette-Poiseuille flow

Entropy generation of mixed convection of SWCNT–water nanofluid filled an annulus with a rotating cylinder and porous lining under LTNE

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