Irreversibility minimization analysis of ferromagnetic Oldroyd-B nanofluid flow under the influence of a magnetic dipole

© 2021, The Author(s). Studies highlighting nanoparticles suspensions and flow attributes in the context of their application are the subject of current research. In particular, the utilization of these materials in biomedical rheological models has gained great attention. Magneto nanoparticles have a decisive role in the ferrofluid flows to regulate their viscoelastic physiognomies. Having such substantial interest in the flow of ferrofluids our objective is to elaborate the melting heat transfer impact in a stretched Oldroyd-B flow owing to a magnetic dipole in the presence of entropy generation optimization. Buongiorno nanofluid model expounding thermophoretic and Brownian features are considered. Moreover, activation energy with chemical reaction is also considered. The Cattaneo–Christov heat flux model is affianced instead of conventional Fourier law. The renowned bvp4c function of MATLAB is utilized to handle the nonlinearity of the system. Impacts of miscellaneous parameters are portrayed through graphical fallouts and numeric statistics. Results divulge that the velocity and temperature profiles show the opposite trend for growing estimates of the ferromagnetic parameter. It is also noticed that the temperature ratio parameter diminishes the entropy profile. Moreover, it is seen that the concentration profile displays a dwindling trend for the Brownian motion parameter and the opposite trend is witnessed for the thermophoretic parameter

Impact of Newtonian heating and Fourier and Fick’s laws on a magnetohydrodynamic dusty Casson nanofluid flow with variable heat source/sink over a stretching cylinder

The present investigation aims to deliberate the magnetohydrodynamic (MHD) dusty Casson nanofluid with variable heat source/sink and modified Fourier’s and Fick’s laws over a stretching cylinder. The novelty of the flow model is enhanced with additional effects of the Newtonian heating, activation energy, and an exothermic chemical reaction. In an exothermic chemical reaction, the energy of the reactants is higher than the end products. The solution to the formulated problem is attained numerically by employing the MATLAB software function bvp4c. The behavior of flow parameters versus involved profiles is discussed graphically at length. For large values of momentum dust particles, the velocity field for the fluid flow declines, whereas an opposite trend is perceived for the dust phase. An escalation is noticed for the Newtonian heating in the temperature profile for both the fluid and dust-particle phase. A comparison is also added with an already published work to check the validity of the envisioned problem

The Impact of Non-Uniform Heat Source/Sink on Chemically Reacting MHD Flow Over An Expanding Sheet

The impact of uneven heat source/sink on the magnetohydrodynamic liquid film flow of Casson fluid in the presence of chemical reaction is investigated theoretically. The transformed governing boundary layer equations are solved numerically by adopting the bvp4c Matlab package. The impact of pertinent parameters, namely, Casson parameter, non-uniform heat source/sink parameters, chemical reaction parameter, magnetic field parameter, unsteadiness parameter and film thickness parameter on the flow, thermal and concentration fields are discussed with the help of graphs. Numerical illustrations of local Nusselt and Sherwood numbers are presented and discussed with the help of tables. Keywords: Chemical reaction, MHD, film flow, non-uniform heat source/sink

Liquid coating with variable thermal conductivity on a pipe under influence of thermal radiation and heat generation

Flow over a pipe or an elongated cylinder is widely applied in many engineering processes like wire coating and pipe coating. This encourages the present study to examine the fluid flow and heat transfer over a horizontal stretching cylinder with the impact of temperature-reliant thermal conductivity and thermal radiation. The influence of heat generation is also considered. The Carreau rheology model is applied to represent the liquid coating. The similarity technique is used to simplify the developed governing equations and then solved by the homotopy analysis method. The effects of the pertinent parameters such as the thermal conductivity parameter and Weissenberg number on the fluid field and heat transfer are studied by applying the calculated series of analytical solutions, which are scrutinized through graphs and tables. The Nusselt number has a negative function with the radiation and thermal conductivity parameters. Furthermore, the Weissenberg number affects the velocity and temperature profiles differently in conditions n < 1 and n ≥ 1, respectively. The present results are essential in optimizing the pipe coating process

ADM solution for Cu/CuO –water viscoplastic nanofluid transient slip flow from a porous stretching sheet with entropy generation, convective wall temperature and radiative effects

A mathematical modelis presented for entropy generation in transient hydromagnetic flow of an electroconductive magnetic Casson (non-Newtonian) nanofluid over a porous stretching sheet in a permeable medium. The Cattaneo-Christov heat flux model is employed to simulate non-Fourier (thermal relaxation) effects. A Rosseland flux model is implemented to model radiative heat transfer. The Darcy model is employed for the porous media bulk drag effect. Momentum slip is also included to simulate non-adherence of the nanofluid at the wall. The transformed, dimensionless governing equations and boundary conditions (featuring velocity slip and convective temperature) characterizing the flow are solved with the Adomian Decomposition Method (ADM). Bejan’s entropy minimization generation method is employed. Cu-water and CuO-water nanofluids are considered. Extensive visualization of velocity, temperature and entropy generation number profiles is presented for variation in magnetic field parameter, unsteadiness parameter, Casson parameter, nanofluid volume fraction, permeability parameter, suction/injection parameter, radiative parameter, Biot number, relaxation time parameter, velocity slip parameter, Brinkman number (dissipation parameter), temperature ratio and Prandtl number. The evolution of skin friction and local Nusselt number (wall heat transfer rate) are also studied. The ADM computations are validated with simpler models from the literature. The solutions show that with elevation in volume fraction of nanoparticle and Brinkman number, the entropy generation magnitudes are increased. An increase in Darcy number also increases the skin friction and local Nusselt number. Increasing magnetic field, volume fraction, unsteadiness, thermal radiation, velocity slip, Casson parameters, Darcy and Biot numbers are all observed to boost temperatures. However, temperatures are reduced with increasing non-Fourier (thermal relaxation) parameter. Greater flow acceleration is achieved for CuO-water nanofluid compared with Cu-water nanofluid although the contrary response is computed in temperature distributions. The simulations are relevant to the high temperature manufacturing fluid dynamics of magnetic nanoliquids, smart coating systems etc

Effect logs of double diffusion on MHD Prandtl nano fluid adjacent to stretching surface by way of numerical approach

AbstractThe current communication is carried to contemplate the unique and novel characteristics of nanofluids by constructing formulation of Prandtl fluid model. The fascinating aspects of thermo diffusion effects are also accounted in this communication. Mathematical modelling is performed by employing boundary layer approach. Afterwards, similarity variables are selected to convert dimensional non-linear system into dimensionless expressions. The solution of governing dimensionless problem is executed by shooting method (SM). Graphical evaluation is displayed to depict the intrinsic behavior of embedded parameters on dimensionless velocity, temperature, solutal concentration and nanoparticle concentration profiles. Furthermore, the numerical variation for skin friction coefficient, local Nusselt number, Sherwood number and nano Sherwood number is scrutinized through tables. The assurance of current analysis is affirmed by developing comparison with previous findings available in literature, which sets a benchmark for implementation of computational approach. It is inferred from the computation that concentration profile increases whereas Sherwood number decreases for progressive values of Dufour solutal number

Differential transform solution for hall and ion slip effects on radiative-convective casson flow from a stretching sheet with convective heating

Magnetohydrodynamic (MHD) materials processing is becoming increasingly popular in the 21st century since it offers significant advantages over conventional systems including improved manipulation of working fluids, reduction in wear and enhanced sustainability. Motivated by these developments, the present work develops a mathematical model for Hall and Ion slip effects on non-Newtonian Casson fluid dynamics and heat transfer towards a stretching sheet with a convective heating boundary condition under a transverse magnetic field. The governing conservation equations for mass, linear momentum and thermal (energy) are simplified with the aid of similarity variables and Ohm’s law. The emerging nonlinear coupled ordinary differential equations are solved with an analytical technique known as the differential transform method (DTM). The impact of different emerging parameters is presented and discussed with the help of graphs and tables. Generally aqueous electro-conductive polymers are considered for which a Prandtl number of 6.2 is employed. With increasing Hall parameter and ion slip parameter the flow is accelerated whereas it is decelerated with greater magnetic parameter and rheological (Casson) fluid parameter. Skin friction is also decreased with greater magnetic field effect whereas it is increased with stronger Hall parameter and ion slip parameter values