Purpose




The purpose of this paper is to examine the combined effects of thermal radiation and magnetic field of molybdenum disulfide nanofluid in a channel with changing walls. Water is considered as a Newtonian fluid and treated as a base fluid and MoS2 as nanoparticles with different shapes (spherical, cylindrical and laminar). The main structures of partial differential equations are taken in the form of continuity, momentum and energy equations.




Design/methodology/approach




The governing partial differential equations are converted into a set of nonlinear ordinary differential equations by applying a suitable similarity transformation and then solved numerically via a three-stage Lobatto III-A formula.




Findings




All obtained unknown functions are discussed in detail after plotting the numerical results against different arising physical parameters. The validations of numerical results have been taken into account with other works reported in literature and are found to be in an excellent agreement. The study reveals that the Nusselt number increases by increasing the solid volume fraction for different shapes of nanoparticles, and an increase in the values of wall expansion ratio α increases the velocity profile f′(η) from lower wall to the center of the channel and decreases afterwards.




Originality/value




In this paper, a numerical method was utilized to investigate the influence of molybdenum disulfide (MoS2) nanoparticles shapes on MHD flow of nanofluid in a channel. The validity of the literature review cited above ensures that the current study has never been reported before and it is quite new; therefore, in case of validity of the results, a three-stage Lobattoo III-A formula is implemented in Matlab 15 by built in routine “bvp4c,” and it is found to be in an excellent agreement with the literature published before.

Magnetohydrodynamic flow of molybdenum disulfide nanofluid in a channel with shape effects

The irreversibility in convective nanofluid flow in the occurrence of a magnetic field (MHD) in a cavity with chamfers is calculated by numerical approach. The nanofluid flow is considered under the impacts of magnetic field and thermal gradient. The continuity, motion and energy equations are solved by applying COMSOL Multiphysics computer package. The impacts of $$({\text{Ha}})$$
 Hartmann number, $$(\gamma )$$
 elevation of magnetic field, nanoparticle volume fraction, heat transmission and entropy analysis on the flow of nanofluid are discussed. Results reveal that, the impacts of volume fraction and the magnetic force on different irreversibility are significant. Moreover, results indicate the existence of a critical $$({\text{Ha}}_{{\text{c}}} )$$
 Hartmann number this represents the frontier between the domains where the magnetic field dominates via its intrinsic effect and its extrinsic effect.

Entropy generation on magneto-convective flow of copper–water nanofluid in a cavity with chamfers

The aim of this study is to present a critical review of the impact of nanofluids on the performance enhancement of PV/T systems. The review has analyzed the effects of nanoparticle type, size, volume fraction and concentration ratio on the performance of PV/T systems. Furthermore, the type of base-fluid, flow channels, and flow types have also been studied comprehensively in relation to nanofluids characteristics and properties. Results have shown that the inclusion of nanofluid enhances the overall efficiency of the PV/T systems. It has been concluded that the organic fluids are better base fluids than water, and nanofluids with better thermal conductivity enhance the maximum efficiency once optimum size, volume fraction and correct concentration ratio of nanofluid are selected. Moreover, straight microchannel and the addition of Fe3O4, SiC and TiO2 nanofluids with low concentration ratio provides better efficiency and flexibility. The motive beyond that is the micro-channels turbulent flow occurs at low Reynolds number. Accordingly, maximum efficiency can be obtained at higher velocity laminar flows. Increasing the velocity to higher ranges of turbulent flow does not allow proper time for heat transfer and can cause clustering of nanoparticles. The observations of this review are proposed to PV/T systems and it is helpful for the thermal system design practitioners towards achieving high efficiency in any thermal system.

Applications of nanofluids in photovoltaic thermal systems: A review of recent advances

The steady two-dimensional flow of an incompressible non-Newtonian Molybdenum Disulfide nanofluid in the presence of source or sink between two stretchable or shrinkable walls under the influence of thermal radiation is investigated numerically. A generalized transformation is applied to convert the constructed set of partial differential equations (PDEs) into the system of non-linear coupled ordinary differential equations (ODEs). The obtained system of ODEs are solved by using Runge-Kutta 4th and 5th order. The influence of physical parameters, shrinking/ stretching parameter, Casson parameter, Hartmann number, Reynolds number, solid volume fraction, opening angle of the channel and radiation parameter on the velocity and temperature distribution are observed for converging and diverging channels. It is noticed that thermal boundary layer thickness is diminished for increased thermal radiation resulting in gradual temperature fall. The results also reveal that velocity and temperature profile both are elevated on raising the stretching parameter and Hartmann number. A comparative analysis is made out to validate the present results.

MHD Flow of Non-Newtonian Molybdenum Disulfide Nanofluid in a Converging/Diverging Channel with Rosseland Radiation

An exertion is executed to explicate thermophysical aspects of viscoelastic fluid flow produced by a nonlinearized stretched surface. Here, viscoelasticity is characterized by Casson fluid model and expressed rheologically in momentum equation. Flow attributes of Casson fluid are thoroughly investigated under transversal magnetized field and along with provision of suction/injection to surface. Flow medium is also considered to be porous. Convective heating is supplied to the surface to depict heat transfer change within the flow domain. Nanosized particles are hanged into the Casson fluid to understand the effectiveness of Brownian motion and thermophoretic forces on the diffusion of particles. Generative chemical reactions are also considered to measure mass transport. Initially, flow narrating differential equations for concerning a problem are attained in differential equations and later on transforming into ordinary differential coupled system via similarity approach. Variations in flow associated distributions against involved parameters are divulged through graphical structures. Wall drag, thermal and mass fluxes are also calculated. Credibility of computing results is tested with the aid of comparison with previously published data in limiting sense.

MHD Casson nanofluid flow over nonlinearly heated porous medium in presence of extending surface effect with suction/injection

In this paper, rheology of laminar incompressible Copper-Kerosene nanofluid in a channel with stretching walls under the influence of transverse magnetic field is investigated. The main structure of the partial differential equations was taken from the law of conservation of mass, momentum and energy equations. Governing boundary layer equations are transformed into nonlinear ordinary differential equations by using similarity variables and then solved with 3-stage Lobatto IIIA formula. Numerical results were compared with another numerical method (Runge-Kutta-Fehlberg) and found excellent agreement. The influence of physical parameters Reynolds number, magnetic number, solid volume fraction, momentum and thermal slip parameters on velocity and temperature profile considered. Numerical results revealed that solid volume fraction decreases the velocity of nanofluid particles near the lower wall of the channel and increase the thermal boundary layer thickness in the channel.

Jawad Reza

Papers

MHD Slip Flow of Cu-Kerosene Nanofluid in a Channel with Stretching Walls Using 3-Stage Lobatto IIIA Formula