Numerical simulation of magnetic nanofluid (MNF) film boiling on cylindrical heated magnet using phase field method

Sedaghatkish, Amir; Sadeghiseraji, Jaber; Jamalabadi, Mohammad Yaghoub Abdollahzadeh

doi:10.1016/j.ijheatmasstransfer.2020.119546

Cited by 18 publications

(5 citation statements)

References 42 publications

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“…The velocity of the flow

was calculated by the Navier–Stokes equation expressed as

where

is the electric force acting on the liquids obtained by coupling the fluid physics with the electrostatics physics and

is the interfacial tension force between the liquids. The interface between the two liquids can be tracked by using a phase field or a level set equation [ 4 , 36 , 37 ]. In the current study, the interface was tracked by using a conservative form of the level set equation [ 38 , 39 ] given as

where

is the level set function and its value changes from ‘0’ (continuous phase) to ‘1’ (dispersed phase),

is the parameter that controls the thickness of the interface, χ is the stability parameter known as the re-initialization parameter and

is known as the artificial flux.…”

Section: Methodsmentioning

confidence: 99%

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

et al. 2020

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The electrohydrodynamic deformation of an emulsion droplet with a clean and particle-covered interface was explored. Here, the electrohydrodynamic deformation was numerically and experimentally demonstrated under the stimuli of moderate and strong electric fields. The numerical method involves the coupling of the Navier–Stokes equation with the level set equation of interface tracking and the governing equations of so-called leaky dielectric theory. The simulation model developed for a clean interface droplet was then extended to a capsule model for densely particle-covered droplets. The experiments were conducted using various combinations of immiscible oils and particle suspensions while the electric field strength ~105 V/m was generated using a high voltage supply. The experimental images obtained by the camera were post-processed using an in-house image processing code developed on the plat-form of MATLAB software. The results show that particle-free droplets can undergo prolate (deformation in the applied electric field direction) or oblate deformation (deformation that is perpendicular to the direction of the applied electric field) of the droplet interface, whereas the low-conductivity particles can be manipulated at the emulsion interface to form a ‘belt’, ‘helmet’ or ‘cup’ morphologies. A densely particle-covered droplet may not restore to its initial spherical shape due to ‘particle jamming’ at the interface, resulting in the formation of unique droplet shapes. Densely particle-covered droplets behave like droplets covered with a thin particle sheet, a capsule. The deformation of such droplets is explored using a simulation model under a range of electric capillary numbers (i.e., the ratio of the electric stresses to the capillary stresses acting at the droplet interface). The results obtained are then compared with the theory and experimental findings. It was shown that the proposed simulation model can serve as a tool to predict the deformation/distortion of both the particle-free and the densely particle-covered droplets within the small deformation limit. We believe that this study could provide new findings for the fabrication of complex-shaped species and colloidosomes.

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“…The velocity of the flow

was calculated by the Navier–Stokes equation expressed as

where

is the electric force acting on the liquids obtained by coupling the fluid physics with the electrostatics physics and

where

is the level set function and its value changes from ‘0’ (continuous phase) to ‘1’ (dispersed phase),

is the parameter that controls the thickness of the interface, χ is the stability parameter known as the re-initialization parameter and

is known as the artificial flux.…”

Section: Methodsmentioning

confidence: 99%

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

et al. 2020

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“…The initial vapour is located at the top of the liquid. The mathematical modelling of the problem is specified in following paragraphs which are obtained from Reference [1]. The governing equation of continuity is…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…The film boiling heat convection exists in a couple of structuring endeavors and engineering applications, for instance, the cooling of electronic contraptions, microchannel heat exchangers, inert cooling, geothermal science, energy storage in phase change material, sun controlled heat exchangers, and so forth [1][2][3][4]. Considering this wide extent of usage, the topic of two-phase flow is engaging for researchers and various assessments have been finished.…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann Simulation of Ferrofluids Film Boiling

Jamalabadi

2020

Processes

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In the present investigation, two phase film boiling of ferrofluids under an external field delivered around a two-dimensional square cross-section heater was investigated using the lattice Boltzmann technique. The purpose of this work is to find the effect of magnetic field magnitude and direction on the Nusselt number in single and double heater geometry. The improving thermal efficiency in the horizontal and vertical placement of heaters is also presented. The governing equations of mass conservation, momentum conservation, and energy conservation are solved by using a central-moments-based Lattice Boltzmann scheme. The air pocket generated around heater raised incorporating magnetic effects. The heat transfer through this advancement has been explored quantitatively and abstractly. The results shows that with the development in the volumetric applied force at the bubble-fluid interface, the bubble boundary layer thickness around the square heater lessened which cause the Nusselt number augmented. Through the parameter study it found that the Nusselt number can be essentially extended by altering the course of magnet shafts, and that film rising outwardly of the bubble. The improvement and advancement of vapour phase in various heater arrangement made two column of bubble rises at the same time, which rose above each heater and in the end changed into one column of bubble. A correlation considering magnitude and angle of the magnetic field on time-averaged Nusselt number is presented. Finally, the Nusselt number can be controlled with the help of the incorporation of other heaters.

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“…% concentration and 50 nm size of Al2O3 nanoparticles. Sedaghatkish et al [10] numerically studied the film boiling on a magnetic heated cylindrical boiling surface. Due to increase in magnetic force on phase, interface vapor layer thickness at the heated surface decreased and Nusselt number increased.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Nucleate Boiling Heat Transfer Performance using SiO₂/Water Nanofluid

Singh

Sharma

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Nucleate boiling regime is the most efficient regime that gives the maximum heat flux at the wall superheat range of 5 °C to 30 °C. In this current study, the nucleate pool boiling heat transfer performance of SiO2/water nanofluid are studied numerically. The effect of volume fraction (0.01 – 0.06 vol. %) of nanofluid on heat transfer coefficient and wall superheat are investigated. The variation in heat transfer coefficient (HTC) & wall superheat with different heat flux are investigated. Eulerian multiphase approach with RPI boiling model is used to carry out the simulation. The pool boiling heat transfer performance increased with rise in volume concentration of nanofluid up to an optimum concentration of 0.05 % and then it starts to decrease. A reduction in wall superheat of 6.7 %, 8.43 %, 11.27 % and 9.3 % are obtained for SiO2/water nanofluid with volumetric concentration of 0.01, 0.02, 0.05 and 0.06 vol. % respectively as compared to base fluid. Heat transfer coefficient enhanced by 3.55 %, 7.2 %, 23.87 % and 19.67 % for SiO2/water nanofluid with volumetric concentration of 0.01, 0.02, 0.05 and 0.06 vol. % respectively as compared to base fluid.

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Numerical simulation of magnetic nanofluid (MNF) film boiling on cylindrical heated magnet using phase field method

Cited by 18 publications

References 42 publications

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

Lattice Boltzmann Simulation of Ferrofluids Film Boiling

Numerical Simulation of Nucleate Boiling Heat Transfer Performance using SiO₂/Water Nanofluid

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Numerical simulation of magnetic nanofluid (MNF) film boiling on cylindrical heated magnet using phase field method

Cited by 18 publications

References 42 publications

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

Deformation of Emulsion Droplet with Clean and Particle-Covered Interface under an Electric Field

Lattice Boltzmann Simulation of Ferrofluids Film Boiling

Numerical Simulation of Nucleate Boiling Heat Transfer Performance using SiO2/Water Nanofluid

Contact Info

Product

Resources

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Numerical Simulation of Nucleate Boiling Heat Transfer Performance using SiO₂/Water Nanofluid