Magnetic field effects on natural convection flow of a non-Newtonian fluid in an L-shaped enclosure

The effect of magnetic field on natural convection heat transfer in an L-shaped enclosure filled with a non-Newtonian fluid is investigated numerically. The governing equations are solved by finite-volume method using the SIMPLE algorithm. The power-law rheological model is used to characterize the non-Newtonian fluid behavior. It is revealed that heat transfer rate decreases for shear-thinning fluids (of power-law index, n?<?1) and increases for shear-thickening fluids (n?>?1) in comparison with the Newtonian ones. Thermal behavior of shear-thinning and shear-thickening fluids is similar to that of Newtonian fluids for the angle of enclosure α?<?60° and α?>?60°, respectively.     

Limit cycles in the presence of convection: a first-order analysis

We consider a diffusion model with limit cycle reaction functions. In an unbounded domain, diffusion spreads pattern outwards from the source. Convection adds instability to the reaction–diffusion system. We see the result of the instability in a readiness to create pattern. In the case of strong convection, we consider that the first-order approximation may be valid for some aspects of the solution behaviour. We employ the method of Riemann invariants and rescaling to transform the reduced system into one invariant under parameter change. We carry out numerical experiments to test our analysis. We find that most aspects of the solution do not comply with this, but we find one significant characteristic which is approximately first order. We consider the correspondence of the Partial Differential Equation with the Ordinary Differential Equation along rays from the initiation point in the transformed system. This yields an understanding of the behaviour.     

Exponential space-dependent heat generation impact on MHD convective flow of Casson fluid over a curved stretching sheet with chemical reaction

Journal of Thermal Analysis and Calorimetry - The present article focuses on the effect of exponential space-dependent heat source on magneto-hydrodynamic Casson fluid flow over a curved stretching...     

Exact solutions in MHD natural convection of a Bingham fluid: fully developed flow in a vertical channel

Journal of Thermal Analysis and Calorimetry - In nature, many fluid-like materials exhibit a yield stress below which they behave like a solid. The Bingham model aims to describe such materials....     

A study of heat and mass transfer of Non-Newtonian fluid with surface chemical reaction

Considering the significance of non-Newtonian fluid usage in manufacturing such as molten plastics, polymeric materials, pulps, and so on, significant efforts have been made to investigate the phenomenon of non-Newtonian fluids. In this article the influences of heat and mass transfer on non-Newtonian Walter's B fluid flow over uppermost catalytic surface of a paraboloid is encountered. An elasticity of the fluid layer is considered in the freestream together with heat source/sink and has the tendency to cause heat flow in the fluid saturated domain. The flow problem of two-dimensional Walter's B fluid is represented using Law of conservation of mass, momentum, heat, and concentration along with thermal and solutal chemical reactive boundary conditions. The governing equations are non-linear partial differential equation and are non-dimensionalized by employing stream function and similarity transformation. The final dimensionless equations yielded are coupled non-linear ordinary differential equations. Furthermore, shooting technique along with RK-4th order method is used to get the numerical results. Graphs and tables are modeled by using MATLAB software to check the effects of Walter's B parameter, Chemical reaction parameter and Thickness parameter on temperature, velocity, and concentration profiles. Tabular analysis shows the results of some physical parameters like skin friction coefficient, Nusselt number and Sherwood number due to the variation of Walter's B parameter, thickness parameter and chemical reactive parameter.     

MHD Williamson micropolar fluid flow pasting a non-linearly stretching sheet under the presence of non linear heat generation/ absorption

This work aims to study the MHD boundary layer flow of Williamson micropolar fluid pasting a non-linearly stretching sheet under the existence of nonlinear heat absorption/generation term, which arises in convection due to high temperature and is the novelty of the present work. The governing equations corresponding to the above physical configuration have been considered in view of the modified Darcy Law with appropriate boundary conditions. Thereafter making use of suitable similarity transformation by introducing stream function, the revised governing equations in the form of ODE with boundary conditions have been obtained. This boundary value problem have been solved numerically by using the shooting technique. The effect of various parameters on flow variables like velocity, temperature, and microrotation has been depicted through graphs. Also, the present analysis's results are compared with those obtained earlier to ensure the numerical validation of the present analysis. In particular, It is observed that the Hartmann number and Williamson parameter have the effect of increasing skin friction.     

A comparative study of heat transfer analysis on ethylene glycol or engine oil as base fluid with gold nanoparticle in presence of thermal radiation

Journal of Thermal Analysis and Calorimetry - The present work addresses to analyse the heat transfer enhancement of unsteady laminar incompressible MHD flow of couple stress nanofluid through a...     

Experimental and modeling study of Newtonian and non-Newtonian fluid flow in pore network micromodels

The in situ rheology of polymeric solutions has been studied experimentally in etched silicon micromodels which are idealizations of porous media. The rectangular channels in these etched networks have dimensions typical of pore sizes in sandstone rocks. Pressure drop/flow rate relations have been measured for water and non-Newtonian hydrolyzed-polyacrylamide (HPAM) solutions in both individual straight rectangular capillaries and in networks of such capillaries. Results from these experiments have been analyzed using pore-scale network modeling incorporating the non-Newtonian fluid mechanics of a Carreau fluid. Quantitative agreement is seen between the experiments and the network calculations in the Newtonian and shear-thinning flow regions demonstrating that the 'shift factor,'alpha, can be calculated a priori. Shear-thickening behavior was observed at higher flow rates in the micromodel experiments as a result of elastic effects becoming important and this remains to be incorporated in the network model.     

Chemical reaction and Soret effect on an unsteady MHD heat and mass transfer fluid flow along an infinite vertical plate with radiation and heat absorption

In the current investigation, it is anticipated to examine the influence of heat absorption and radiation on an unsteady transient MHD heat and mass transfer natural convective flow of an optically thin non-Grey Newtonian fluid through an abruptly started infinite vertical porous plate with ramped wall temperature and plate velocity in the presence of Soret and chemical reaction of the first order is solved precisely. Using the similarity variables, the governed PDE's are converted into dimensionless governing equations and they are solved numerically by employing the finite element technique. Numerical calculations and graphs are used to illustrate the important features of the solution on fluid flow velocity, heat, and mass transfer characteristics under different quantities of parametric circumstances entering into the problem. Moreover, we computed the physical variables such as the coefficient of drag force, rate of heat, and mass transfer. The findings indicate that when the thermal radiation parameter increases, the thermal boundary layer becomes thinner. To establish the veracity of our present results, we compared them to previously published research and found substantial concordance.     

Influence of heat transfer on MHD Carreau fluid flow due to motile cilia in a channel

Journal of Thermal Analysis and Calorimetry - Mucus transport mediated by motile cilia in the airway is an important defense mechanism for prevention of respiratory infections. Cilia motility can...     

Illustration of chemical reaction on the flow of viscous fluid in a deformable permeable layer: A numerical approach

In this article, analysis is carried out for the flow of viscous liquid in a deformable permeable layer. Influence of chemical reaction is considered that will affect the flow behavior. The governing equation describes the coupling between the solid deformation, fluid movement and concentration in the porous layer. However, these complex transformed designed problems are numerically examined retaining “Runge-Kutta fourth-order” in coordination with shooting method. Computational results for the numerous parameters on the flow phenomena such as solid displacement profiles are presented graphically. Moreover, the significant finding of the results is; increasing viscous drag retards the momentum within the permeable stratum whereas increasing particle concentration has opposite impact on the solid displacement within the domain.     

Magneto-hydrodynamical numerical simulation of heat transfer in MHD stagnation point flow of Cross fluid model towards a stretched surface

Here formulation and computations are presented to introduce the novel concept of activation energy in chemically reacting stagnation point flow towards a stretching sheet. Constitutive expression for Cross liquid is taken into account. Magnetic field is utilised in the transverse direction. Application of suitable variables generates the non-linear differential systems. Numerical solution by Runge–Kutta–Fehlberg approach is presented. Characteristics for the significant variables like Weissenberg number, Hartmann number, Schmidt number, activation energy chemical reaction parameter, velocity ratio parameter and Prandtl number on the physical quantities are addressed through graphs and tables. Our computations reveal that species concentration rises via larger activation energy parameter whereas it decays when Schmidt number is incremented. The Weissenberg number has opposite characteristics for local Nusselt and Sherwood numbers when compared with surface drag force.     

Natural convection of a non-Newtonian ferrofluid in a porous elliptical enclosure in the presence of a non-uniform magnetic field

Journal of Thermal Analysis and Calorimetry - In the present study, laminar natural convection of a non-Newtonian ferrofluid inside an elliptical porous cavity was numerically simulated in the...     

Thermodynamical analysis of heat transfer of gravity-driven fluid flow via fractional treatment: an analytical study

Journal of Thermal Analysis and Calorimetry - This paper presents that how the characteristics of thermal radiation depend on the temperature of unsteady gravity-driven thermal convection flow of...     

Numerical study on turbulent natural convection and radiation heat transfer of nanofluids in a differentially heated square enclosure

Journal of Thermal Analysis and Calorimetry - Due to the low performance observed during natural convection with fluids such as air and water, nanofluid research was carried out to analyse them for...     

Numerical analysis of mixed convection heat transfer and laminar flow in a rectangular inclined micro-channel totally filled with Water/Al2O3 Nano fluid

A numerical analysis was carried out of mixed convection heat transfer for a laminar flow in a rectangular inclined microchannel totally filled with a water/Al2O3 nanofluid. The governing conservation equations are translated into a dimensionless form using the thermal single relaxation time and they modify the lattice Boltzmann method with double distribution functions. The viscous dissipation effects are adapted to the energy equation. The effects of nanoparticle volume fractions ? (0?≤???≤?0.04) and inclination angles γ (0°?≤?γ?≤?60°) on the flow of the nanofluid and the heat transfer are investigated. The obtained results are presented in terms of streamlines, isotherms, slip velocity, wall temperature and Nusselt number. The results show that the higher values of the volume fraction of Al2O3 and the large values of inclination angles improve the heat transfer rate.

     

A comparative analysis of a heat pump application with grey wastewater source for domestic hot water preparation in hotels

Journal of Thermal Analysis and Calorimetry - System for domestic hot water (DHW) preparation generally represents a considerable portion of the energy and water consumption in hotels worldwide. As...     

Scaling group analysis of bioconvective micropolar fluid flow and heat transfer in a porous medium

Journal of Thermal Analysis and Calorimetry - The current and potential applications of bioconvection renewed drive for theoretical research on synthesis and process control in biofuel cells and...     

A computational study on mixed convection with surface radiation in a channel in presence of discrete heat sources and vortex generator based on RSM

Journal of Thermal Analysis and Calorimetry - Numerical simulation of mixed convection and surface radiation in a horizontal rectangular channel with five discrete heat sources protruded from the...     

Natural convection and radiation heat transfer of power-law fluid food in symmetrical open containers

Journal of Thermal Analysis and Calorimetry - In order to avoid insufficient sterilization caused by uneven heating and nutrition loss generated by excessive heating, researchers and scientists...