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.

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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 exploration examines the Cattaneo–Christov double diffusions theory in magneto-Cross nanomaterial flow conveying gyrotactic microorganisms over an extending horizontal cylinder/plate under the aspects of velocity slippage, and activation energy with chemically reacting features. The phenomena of thermophoresis, Brownian movement, and thermal radiation are also incorporated. Utilization of the adopted similarity transformations makes it convenient to transform our governing nonlinear higher-order coupled PDEs into ODEs which are further solved numerically by adopting well-known MATLAB function bvp4c. The quantitative outcomes of emerging thermo-physical and geometrical parameters on the associated non-dimensional profiles of interest are anatomized via requisite graphs and numerically erected tabular forms. It is detected that fluid velocity components decline due to upgraded magnetic field and velocity slippage parameter. When thermal time relaxation parameter varies from 0.0 to 0.9, Nusselt number augments about $$22.02\%$$
 for cylindrical surface and about $$23.61\%$$
 for plate surface. Likewise, with the same variations in thermal time relaxation parameter Sherwood number increases about $$17.32\%$$
 for cylindrical surface and about $$18.24\%$$
 for plate surface. Moreover, comparative exploration of the emerging flow features over a flat plate, and cylindrical surface is reported. It is visualized that flat plate offers less temperature than cylindrical surface when flow occurs. The results would offer primary guidance for many industrial, biological, medical and ecological challenges, for instance, bio-fuel, bio-diesel, ethanol, biological tissues, bio-fertilizers, bio-micro-systems, reproduction, infection, and marine life ecosystems, etc.

Investigation of Cattaneo–Christov Double Diffusions Theory in Bioconvective Slip Flow of Radiated Magneto-Cross-Nanomaterial Over Stretching Cylinder/Plate with Activation Energy

This paper aims to delineate the heat transfer enhancement and entropy generation of a magnetohydrodynamic (MHD) flow of a viscous incompressible electrically conducting non-Newtonian Casson hybrid nanofluid between two infinite parallel non-conducting plates channel in a rotating frame. Copper and aluminium oxide nanoparticles are dispersed in ethylene glycol (EG) as a base fluid. Casson model is deployed here to describe the constitutive behaviour of non-Newtonian fluids. The thermal radiation, viscous dissipation and Joule heating (Ohmic dissipation) effects are included in this model. Closed-form solutions are obtained for constitutive equations. Graphs and tables are presented and illustrated to disclose the impact of significant flow parameters on the flow system. The shear stresses and the rate of heat transfer are discussed numerically, and their numerical values for pertinent physical parameters are tabulated. The total entropy generation rate and Bejan number are also discussed and their interpretations with the physical parameters are conferred via graphs. The results obtained from the parametric analysis manifest that the temperature field is boosted up due to the high intensity of magnetic field as well as Coriolis force. The intensification of magnetic parameter contributes to an increase in the rate of heat transfer at the channel walls. The entropy generation can be minimized by improving Casson parameter. Moreover, a comparison between the flows of Casson hybrid nanofluid (Cu-Al2O3/EG) and Casson nanofluid (Cu-EG) is reported. Minimization in entropy generation is achieved for Casson hybrid nanofluid in comparison with Casson nanofluid.

Feature of Entropy Generation in Cu-Al2O3/Ethylene Glycol Hybrid Nanofluid Flow Through a Rotating Channel

In modern era, thermo-migration of microorganisms is an appealing research topic in bio-nanotechnology, bio engineering, and biomedical. In this context, a mathematical model describing thermo-bioconvection of Sutterby nanofluid flow including motile gyrotactic microorganisms near a perforated Riga plate under the physical impacts of heat radiation, and Arrhenius kinetics associated with binary chemical reaction is formulated and simulated here. The Darcy-Forchheimer (DF) law is applied to determine the porosity of porous media. The Grinberg term is taken for the Lorentz force owing to the parallel Riga plate wall. Appropriate translations are discharged to turn the constitutive partial differential equations (PDEs) into ordinary differential equations (ODEs), that are numerically computed by opting the Runge–Kutta-Fehlberg method (RKF-45) along with shooting strategy. The physical insights of various controlling variables on the transport profiles, Sherwood number, Nusselt number, and microorganisms density number are exemplified through requisite graphs and tables. It must be admitted that with enlarging Darcy number, the nanofluid velocity declines, while Forchheimer number has opposite consequence on it. The motile microorganisms density sharply decreases for improving values of activation parameter. The present modeling would provide preliminary guidances in a variety of biotechnological and industrial applications. 

Themo-bioconvection of gyrotactic microorganisms in a polymer solution near a perforated Riga plate immersed in a DF medium involving heat radiation, and Arrhenius kinetics

The current work seeks to investigate the thermal bio-convection impact of gyrotactic microorganisms in a Cross nano liquid flow through a slippery horizontal cylinder with Arrhenius activation energy involvement. This nanofluid model incorporates magnetic field, chemical reaction, Brownian motion, thermophoresis, and gravitation. The set of nonlinear formulating PDEs is converted to a set of ODEs by utilising requisite similarity transformations. The numerical computation of the altered ODEs is performed using the fourth-order Runge-Kutta-Fehlberg approach plus shooting strategy. The physical consequences of significant physical factors on non-dimensional profiles of interest are displayed in the form of figures and tables. The outcomes revealed that raising the activation energy and chemical reaction parameters significantly increases nanoparticle concentration. However, the microorganism's concentration difference parameter may be used to control the process of microorganism intensity. Using Response-Surface-Methodology (RSM), the statistical analysis (SA) of Nusselt and Sherwood numbers is performed to investigate the effectiveness of activation energy, thermophoresis, and Brownian motion parameters. Activation energy and thermophoresis parameters are both favourably sensitive to the Nusselt number. The study’s new findings may impact the biotechnology and automotive industries. 

Magneto-thermo-bioconvection of a chemically sensitive Cross nanofluid with an infusion of gyrotactic microorganisms over a lubricious cylindrical surface: Statistical analysis

Entropy Generation Analysis of MHD Slip Flow of Non-Newtonian Cu-Casson Nanofluid in a Porous Microchannel Filled with Saturated Porous Medium Considering Thermal Radiation

The purpose of this article is to analyze the heat and mass transfer with entropy generation during magnetohydrodynamics (MHD) flow of non-Newtonian Sisko nanofluid over a linearly stretching cylinder under the influence of velocity slip, chemical reaction and thermal radiation. The Brownian motion, thermophoresis and activation energy are assimilated in this nanofluid model. Convective boundary conditions on heat and mass transfer are considered. The physical model may have diverse applications in several areas of technology underlying thermohydrodynamics including supercritical fluid extraction, refrigeration, ink-jet printing and so on.,The dimensional governing equations are nondimensionalized by using appropriate similarity variables. The resulting boundary value problem is converted into initial value problem using the method of superposition and numerically computed by employing well-known fourth-order Runge–Kutta–Fehlberg approach along with shooting technique (RKF4SM). The quantitative impacts of emerging physical parameters on the velocity, temperature, concentration, skin friction coefficient, Nusselt number, Sherwood number, entropy generation rate and Bejan number are presented graphically and in tabular form, and the salient features are comprehensively discussed.,From graphical outcomes, it is concluded that the slip parameters greatly influence the flow characteristics. Fluid temperature is elevated with rising radiation parameter and thermal Biot number. Nanoparticle concentration is reported in decreasing form with activation energy parameter. Entropy is found to be an increasing function of magnetic field, Brownian motion and material parameters. The entropy is less generated for shear-thinning fluid compared to shear-thickening as well as Newtonian fluids in the system.,Till now no study has been documented to explore the impact of binary chemical reaction with Arrhenius activation energy on entropy generation in an MHD boundary layer flow of non-Newtonian Sisko nanofluid over a linear stretching cylinder with velocity slip and convective boundary conditions.

Activation energy impact on radiated magneto-Sisko nanofluid flow over a stretching and slipping cylinder: entropy analysis

Entropy Generation Minimization of Magnetohydrodynamic Slip Flow of Casson H2O + Cu Nanofluid in a Porous Microchannel

\nPurpose\nTo amend the efficiency of engineering processes and electronic devices, it is very urgent to assess the irreversibility in the term entropy generation (EG). The efficiency of energy transportation in a system can be improved by minimization of the rate of EG. In this context, the aim of the present study is to estimate irreversible losses of an unsteady magnetohydrodynamic (MHD) flow of a viscous incompressible electrically conducting non-Newtonian molybdenum disulfide-polyethylene glycol Casson nanofluid past a moving vertical plate with slip condition under the influence of Hall current, thermal radiation, internal heat generation/absorption and first-order chemical reaction. Molybdenum disulfide (MoS2) nanoparticles are dispersed in the base fluid polyethylene glycol (PEG) to make Casson nanofluid. Casson fluid model is considered to characterize the rheology of the non-Newtonian fluid, whereas Rosseland approximation is adopted to simulate the thermal radiative heat flux in the energy equation.\n\n\nDesign/methodology/approach\nThe closed-form solutions are obtained for the model equations by using the Laplace transform method (LTM). Graphs and tables are prepared to examine the impact of pertinent flow parameters on the pertinent flow characteristics. The energy efficiency of the system via the Bejan number is studied extensively.\n\n\nFindings\nAnalysis reveals that Hall current has diminishing behavior on entropy production of the thermal system. Strengthening of the magnetic field declines the velocity components and prop-ups the rate of EG. Adding nanoparticles into the base fluid reduces the EG, whereas there are an optimum volume fraction of nanoparticles for which the EG is minimized. Further, the rate of decay of EG is prominent in molybdenum disulfide-polyethylene glycol in comparison to PEG.\n\n\nPractical implications\nThe results of this study would benefit the industrial sector in achieving the maximum heat transfer at the cost of minimum irreversibilities with an optimal choice of embedded thermophysical parameters. In view of this agenda, this study would be adjuvant in powder technology, polymer dynamics, metallurgical process, manufacturing dynamics of nano-polymers, petroleum industries, chemical industries, magnetic field control of material processing, synthesis of smart polymers, etc.\n\n\nOriginality/value\nThe novelty of this study is to encompass the analytical solution by using the LTM. Such an exact solution of non-Newtonian fluid flow is rare in the literature. Limited research articles are available in the field of EG analysis during the flow of non-Newtonian nanoliquid subject to a strong magnetic field.\n

S. Das

Papers

Investigation of Cattaneo–Christov Double Diffusions Theory in Bioconvective Slip Flow of Radiated Magneto-Cross-Nanomaterial Over Stretching Cylinder/Plate with Activation Energy

Entropy Generation Analysis of MHD Slip Flow of Non-Newtonian Cu-Casson Nanofluid in a Porous Microchannel Filled with Saturated Porous Medium Considering Thermal Radiation

Activation energy impact on radiated magneto-Sisko nanofluid flow over a stretching and slipping cylinder: entropy analysis

Entropy Generation Minimization of Magnetohydrodynamic Slip Flow of Casson H2O + Cu Nanofluid in a Porous Microchannel

Assessment of irreversible losses of non-Newtonian nanofluid flow underlying Hall current, chemical reaction and thermal radiation