Numerical analysis of magnetic field effects on the heat transfer enhancement in ferrofluids for a parabolic trough solar collector

Khosravi, Ali; Malekan, Mohammad; Assad, Mamdouh El Haj

doi:10.1016/j.renene.2018.11.015

Cited by 93 publications

(26 citation statements)

References 49 publications

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“…The results showed that when using nanofluid in the system, the collector efficiency achieves a maximum value of approximately 7%. Khosravi et al [77] analyzed the heat transfer parameter with the nanofluid used under a certain magnetic field and made calculations using the CFD law.…”

Section: Parabolic Trough Solar Collectors and Nanofluid Usage In Thementioning

confidence: 99%

“…[76] 2015 MCNT-mineral oil When using MCNT / mineral oil nanofluid, efficiency increased 4-5% at 0.2% and 5-7% at 0.3%. [77] 2018 Fe3O4-Therminol 66 It is determined that the magnetic field parameter could change various properties of the collector. productivity and exit temperature of the system can be increased with this parameter.…”

Section: Parabolic Trough Solar Collectors and Nanofluid Usage In Thementioning

confidence: 99%

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Güneş Kolektörlerinde Nanoakışkanların Kullanılmasının Etkileri

Ünvar

Menlik

2021

Politeknik Dergisi

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The importance of using solar energy, one of the renewable energy sources, has started to be understood more recently. The negative environmental effects and limited amounts of fossil fuels have led to increased demand for renewable energy sources worldwide and the production of various models and devices has accelerated to take advantage of solar energy, which is the basis of all energy sources. Using solar collectors as a way to benefit from solar energy has been used for many years. Although solar collectors are generally divided into 4 types as flat plate (FPSC), evacuated tube (ETSC), parabolic (PSC) and heat pipe (HPSC), these types can also be divided into separate types with many different features. The most commonly used solar collector type in the world is Flat Plate Solar Collector. The most important reasons for this are being cheap, easily produced and applied in various ways. Yet, the thermal productivity of FPSCs decreases below 40% in non-ideal climate conditions with low surrounding temperature. The existence of such disadvantages of FPSCs led to the production of Evacuated Tube Solar Collectors. With the advancing technology, the utilization of heat pipes in collectors has come to the agenda and as a result of the studies conducted, it has been determined that the use of heat pipe improves efficiency. In addition, the use of nanofluids in solar collectors and heat pipes has become quite common, and many studies have been carried out especially on this subject recently. The primary objective is always to improve the performance of the system and achieve efficiency. In this way, solar energy will be used in the most effective way and world energy supply demand will be met by using renewable resources.

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Section: Parabolic Trough Solar Collectors and Nanofluid Usage In Thementioning

confidence: 99%

Section: Parabolic Trough Solar Collectors and Nanofluid Usage In Thementioning

confidence: 99%

Güneş Kolektörlerinde Nanoakışkanların Kullanılmasının Etkileri

Ünvar

Menlik

2021

Politeknik Dergisi

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“…They showed that heat transfer rate depends on the applied magnetic field direction. The impact of a magnetic field on the heat transfer augmentation of ferrofluid flow in the pipe of parabolic solar collector was analyzed by Khosravi et al [30]. Their results revealed that thermal performance can be enhanced by increasing particle volume fraction and magnetic field strength.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of magnetic field effect on the ferrofluid forced convection and entropy generation in a curved pipe

Soltanipour

Gharegöz

Oskooee

2020

J Braz. Soc. Mech. Sci. Eng.

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This paper presents the effect of a magnetic field on the ferrofluid flow pattern, heat transfer and entropy generation in a curved pipe. A non-uniform magnetic field is applied to ferrofluid (water + 2% vol. Fe 3 O 4 nanoparticles) flow and under the constant heat flux boundary condition. Governing equations are solved by the finite volume method and based on the SIMPLE algorithm. The major objective of this work is to illustrate the effects of circumferential angle (0 • ≤ ≤ 180 •) and strengths of a magnetic field 0 ≤ Mn ≤ 3 × 10 6 on the hydro-thermal behavior and entropy production rate. It is found that circumferential angle of the magnetic source plays an important role in hydro-thermal performance of a curved pipe. At low magnetic numbers, the optimal circumferential location of the magnetic source is opt = 180 • which leads to the maximum heat transfer enhancement and hydro-thermal performance and the minimal entropy generation rate. For high magnetic numbers, the optimal operating condition occurs at = 0 • and = 60 • depending on the magnetic number. Second law analysis reveals that the major source of entropy generation comes from heat transfer irreversibility which reduces significantly by applying a magnetic field. In the range of studied parameters, the maximum heat transfer enhancement is about 29% which occurs at = 0 • and Mn = 3 × 10 6. Keywords Curved pipe • Entropy generation • Ferrofluid • Heat transfer enhancement • Magnetic field List of symbols C Specific heat at constant pressure (Jkg −1 K −1) d p Particle diameter (m) Ec Eckert number (−) H Magnetic field intensity (Am −1) I Electric current (A) K Thermal conductivity (Wm −1 K −1) k B Boltzmann constant (1.380648 × 10 −23 J K −1) Ms Saturation magnetization (Am −1) Mn Magnetic number (−) m p Magnetic moment of nanoparticles (Am 2) Nu Nusselt number(−) P Pressure (Pa) Pr Prandtl number (−) q′′ Heat flux (Wm −2) q* Non-dimensional heat flux (−) r Radial coordinate (m) R c Radius of curvature (m) Re Reynolds number (−) S f Volumetric entropy generation rate due to friction (Wm −3 K −1) S gen Total volumetric entropy generation rate (Wm −3 K −1) S T Volumetric entropy generation rate due to heat transfer (Wm −3 K −1) T Temperature (K) u, v, w Velocity components (ms −1) x, y, z Cartesian coordinates (m) Greek symbols α Particle volume fraction (−) μ Dynamic viscosity (Pa s −1) μ B Bohr magneton (9.274 × 10 −24 Am 2) μ o Vacuum permeability (Tm A −1) ξ Langevin parameter (−) ρ Density (kg m −3) ϕ v Viscous dissipation function (s −1

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“…Hariri et al [32] and Mokhtari et al [33] were analyzed the effects of magnetic field on ferrofluid performance in tubes without and with twisted tapes. Khosravi et al [34], [35] have investigated the ferrofluid characteristics and its heat transfer properties in the presence of magnetic field for in tube for different industrial applications. And more recently, Sheikholeslami et al [36] evaluated the influence of non-uniform magnetic field on heat transfer enhancement of ferrofluid in a 90° elbow channel.…”

Section: Introductionmentioning

confidence: 99%

The influence of magnetic field on heat transfer of magnetic nanofluid in a double pipe heat exchanger proposed in a small-scale CAES system

Malekan

Khosravi

Zhao

2019

Applied Thermal Engineering

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Globally, the integration of renewable energy (which has an intermittent nature) into the power system requires the system operators to improve the system performance to be able to effectively handle the variations of the power production in order to balance the supply and demand. This problem is seen as a major obstacle to the expansion of renewable energy if it is not handled in a suitable way. Efficient electricity storage technology is one of the feasible solutions. The current study proposes Fe3O4/water nanofluid under magnetic field as the secondary fluid in the proposed double pipe heat exchanger before the cavern. The heat of compressed air is absorbed by the secondary fluid and it is stored in an isolation tank. This stored fluid is used to warm up the air that leaves the cavern for expanding in the turbine. The results demonstrated that increasing the mass flow rate of secondary fluid decreases the cavern temperature. Also, the value of convective heat transfer of ferrofluid increases when the volume fraction of nanoparticle as well as magnetic field increases. Furthermore, increasing the volume fraction and magnetic field increases the pressure drop and friction factor of ferrofluid.

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Numerical analysis of magnetic field effects on the heat transfer enhancement in ferrofluids for a parabolic trough solar collector

Cited by 93 publications

References 49 publications

Güneş Kolektörlerinde Nanoakışkanların Kullanılmasının Etkileri

Güneş Kolektörlerinde Nanoakışkanların Kullanılmasının Etkileri

Numerical study of magnetic field effect on the ferrofluid forced convection and entropy generation in a curved pipe

The influence of magnetic field on heat transfer of magnetic nanofluid in a double pipe heat exchanger proposed in a small-scale CAES system

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