Mixed Convection Effects Research Articles

Entropy generation in a ciliary flow of an Eyring-Powell ternary hybrid nanofluid through a channel with electroosmosis and mixed convection.

Drug delivery systems, where the nanofluid flow with electroosmosis and mixed convection can help in efficient and targeted drug delivery to specific cells or organs, could benefit from understanding the behavior of nanofluids in biological systems. In current work, authors have studied the theoretical model of two-dimensional ciliary flow of blood-based (Eyring-Powell) nanofluid model with the insertion of ternary hybrid nanoparticles along with the effects of electroosmosis, magnetohydrodynamics, thermal radiations, and mixed convection. Moreover, the features of entropy generation are also taken into consideration. The system is modeled in a wave frame with the approximations of large wave number and neglecting turbulence effects. The problem is solved numerically by using the shooting method with the assistance of computational software "Mathematica" for solving the governing equation. According to the temperature curves, the temperature will increase as the Hartman number, fluid factor, ohmic heating, and cilia length increase. It is also disclosed that ternary hybrid nanoparticles result in a change in flow rate when other problem parameters are varied, and the same is true for temperature graphs. Engineers and scientists can make better use of nanofluid-based cooling systems in electronics, automobiles, and industrial processes with the aid of the study's findings.

A theoretical stability of mixed convection 3D Sutterby nanofluid flow due to bidirectional stretching surface

Host (base) fluids are unable to deliver efficient heating and cooling processes in industrial applications due to their limited heat transfer rates. Nanofluids, owing to their distinctive and adaptable thermo-physical characteristics, find a widespread range of practical applications in various disciplines of nanotechnology and heat transfer equipment. The novel effect of this study is to determine the effects of mixed convection, and activation energy on 3D Sutterby nanofluid across a bi-directional extended surface under the impact of thermophoresis diffusion and convective heat dissipation. The flow equations are simplified in terms of partial differential equations (PDEs) and altered to non-dimensional ODEs by implementing classical scaling invariants. Numerical results have been obtained via the bvp4c approach. The physical insights of crucial and relevant parameters on flow and energy profiles are analysed through plotted visuals. Some factors have multiple solutions due to shrinking sheets. So stability analysis has been adapted to analyses stable solutions. Graphical representations demonstrate the reliability and accuracy of the numerical algorithm across a variety of pertinent parameters and conditions. A comparison between existing results and previously published data shows a high degree of compatibility between the two datasets. The present study extensively explored a multitude of practical applications across a diverse spectrum of fields, including but not limited to gas turbine technology, power generation, glass manufacturing, polymer production, wire coating, chemical production, heat exchangers, geothermal engineering, and food processing.

Multi-step differential transform method for both Hall currents and mixed convection effects on MHD flow of non-Newtonian fluid with Al2 O3 nanoparticles

Multi-step differential transform method for both Hall currents and mixed convection effects on MHD flow of non-Newtonian fluid with Al2 O3 nanoparticles

Numerical Study of Mixed Convection of Buoyant Twin Jet

Abstract The effect of mixed convection of twin vertical jets is investigated numerically in this paper. The results are presented specifically for flows affected by buoyancy for two parallel jets of same velocities ranging between 0.25 m/s and 5.0 m/s and temperatures between 295 K and 320 K. Both jets generate a slow flow with a temperature difference (with the ambient flow) less or equal to 32 °C (305 K). Predictions of dynamical and thermal parameters are obtained for the merging and combining regions. This study reveals that the trajectory of the two jets is strongly influenced by the ratio of buoyancy to inertial forces. Results indicate that, relative to isotherm jets, the location along the vertical symmetry plane at which the two jets merge (merging point) decreases with increasing jet inlet temperature. It was also found that the location of the merging point is shifted toward the confining wall as the velocity of the jets increases. The behavior law (linear regression), relating to the expansion of the jet, is not verified in the developed region for each value of the inlet velocity and temperature. This is explained by the fact that natural convection is more predominant than forced convection. The results show that the self-similarity of the cross profiles of the mean velocity and the behavior law relating to the expansion of the jet are obtained throughout the developed region.

The computational model of nanofluid considering heat transfer and entropy generation across a curved and flat surface

The entropy generation analysis for the nanofluid flowing over a stretching/shrinking curved region is performed in the existence of the cross-diffusion effect. The surface is also subjected to second-order velocity slip under the effect of mixed convection. The Joule heating that contributes significantly to the heat transfer properties of nanofluid is incorporated along with the heat source/sink. Furthermore, the flow is assumed to be governed by an exterior magnetic field that aids in gaining control over the flow speed. With these frameworks, the mathematical model that describes the flow with such characteristics and assumptions is framed using partial differential equations (PDEs). The bvp4c solver is used to numerically solve the system of non-linear ordinary differential equations (ODEs) that are created from these equations. The solutions of obtained through this technique are verified with the available articles and the comparison is tabulated. Meanwhile, the interpretation of the results of this study is delivered through graphs. The findings showed that the Bejan number was decreased by increasing Brinkman number values whereas it enhanced the entropy generation. Also, as the curvature parameter goes higher, the speed of the nanofluid flow diminishes. Furthermore, the increase in the Soret and Dufour effects have enhanced the thermal conduction and the mass transfer of the nanofluid.

High-Fidelity Simulations of Shield Assembly Mixed-Convection Flows with Applications Toward Reduced-Resolution Modeling

Flow circulation and heat removal through shield and reflector assemblies can have major impacts on safety in long transients for sodium fast reactors (SFRs). These transients are typically categorized by reduced flow rates and large-scale organized flow patterns, including potential intra-assembly circulation. Such low-flow cases can provide challenges for experiments because of complications in measuring the flow rates and temperatures with high accuracy in different areas. This consequently also raises the uncertainty of many modeling approaches for these phenomena. In an effort to address some of these issues, high-fidelity large eddy simulations are performed using the highly parallel solver NekRS. A 19-pin configuration of a tight-lattice wire-wrapped hexagonal bundle (pitch-to-diameter ratio = 1.07), representing a prototypical internal configuration of a shield assembly, was investigated. The sodium flow was set at a bundle Reynolds number of 2000, with simulations being performed for modified Richardson numbers of 0.0 (i.e., no buoyancy), 0.01, and 0.04, where mixed-convection effects are anticipated. The flow and temperature fields for these cases are discussed in detail. The high-fidelity data should prove useful as reference data for expanding and improving on various reduced-resolution approaches. A basic framework for combining subchannel and computational fluid dynamics methodologies in SFRs is also presented, with preliminary results from simulations of light water reactor bundles and a discussion of changes that need to be made for potential application to SFRs.

Homotopic simulation of MHD bioconvective flow of water-based hybrid nanofluid over a thermal convective exponential stretching surface

PurposeWhilst a modest number of investigations have been undertaken concerning nanofluids (NFs), the exploration of fluid flow under exponentially stretching velocities using NFs remains comparatively uncharted territory. This work presents a distinctive contribution through the comprehensive examination of heat and mass transfer phenomena in the NF ND–Cu/H2O under the influence of an exponentially stretching velocity. Moreover, the investigation delves into the intriguing interplay of gyrotactic microorganisms and convective boundary conditions within the system.Design/methodology/approachSimilarity transformations have been used on PDEs to convert them into dimensionless ODEs. The solution is derived by using the homotopy analysis method (HAM). The pictorial notations have been prepared for sundry flow parameters. Furthermore, some engineering quantities are calculated in terms of the density of motile microbes, Nusselt and Sherwood numbers and skin friction, which are presented in tabular form.FindingsThe mixed convection effect associated with the combined effect of the buoyancy ratio, bioconvection Rayleigh constant and the resistivity due to the magnetization property gives rise to attenuating the velocity distribution significantly in the case of hybrid nanoliquid. The parameters involved in the profile of motile microorganisms attenuate the profile significantly.Practical implicationsThe current simulations have uncovered fascinating discoveries about how metallic NFs behave near a stretched surface. These insights give us valuable information about the characteristics of the boundary layer close to the surface under exponential stretching.Originality/valueThe novelty of the current investigation is the analysis of NF ND–Cu/H2O along with an exponentially stretching velocity in a system with gyrotactic microorganisms. The investigation of fluid flow at an exponentially stretching velocity using NFs is still relatively unexplored.

A transient numerical approach for phase change material effect on mixed convection in an open cavity

The effects of heated wall locations on mixed convection flow in a 2-D rectangular open cavity are investigated numerically using ANSYS-Fluent software. The flow is supposed to be a two-dimensional laminar and is regulated by parameters such as Reynolds, Re (100 and 200), and Richardson numbers, Ri (1, 5, 10, 15 and 20). One of the walls is heated uniformly, while the others are adiabatic. The heated wall might be vertical on the inflow and outflow sides or horizontal on the bottom of the cavity. The flow is stable at all Re and Ri values except at Ri = 20 and Re = 100 for bottom heated wall. It is found that using phase change material (PCM) reduces flow variations in the cavity. Further, the mixed convection effects are developed with increased Richardson number. This pushes the recirculating zone upstream and creates an unstable flow behavior. According to the results, the condition that minimized the fluctuations in the flow direction was the application of PCM to the bottom heated wall case. Therefore, thermal control of the flow is most efficient in this condition. The PCM melting rate is quite high for the Re = 200 condition as there is higher convective heat transfer in all cases than the Re = 100. Dimensionless wall temperature values with PCM case are lower than without PCM case for all conditions. The decrease of this parameter in bottom heated case is about 18.8% while 43.1% and 56.3% for left and right heated case, respectively. Additionally, the highest average Nusselt number is found for the bottom heated case for the same Re, with and without PCM cases.

Impacts of entropy generation for nonlinear radiative peristaltic transport of Powell-Eyring nanofluid: A numerical study

The importance of mathematical simulation in studying biological fluids extends to various medical disciplines. The peristaltic process is crucial for comprehending different biological flows. Additionally, nanoparticles serve essential functions in a range of engineering and industrial applications, such as heat exchangers, boilers, cooling systems, and chemical engineering. This current study addresses the numerical investigation of entropy optimization for (magnetohydrodynamic) MHD peristaltic activity of Eyring-Powel nanoliquid. Here channel boundaries are flexible in nature. Effects of mixed convection and hall current were also considered. Slip conditions are imposed on channel walls. Viscous dissipation and nonlinear thermal radiation are also present in thermal transport. Brownian movement and thermophoresis aspects are considered in the nanoliquid model. Chemical reaction of order first is also present the mass transport. Simplification of transport expressions is done by operating lubrication approach. The resulting system of nonlinear equations is numerically tackled. Both numerical techniques for heat transfer rate are validated by comparing them to numerical results computed by MATLAB using bvp4c and NDSolve. Graphical analysis is carried out for different flow parameters by plotting velocity, temperature, concentration, and entropy.

Soret and Dufour effects on dissipative Jeffrey nanofluid flow over a curved surface with nonlinear slip, activation energy and entropy generation

Nanofluids have potential abilities and thermal features and provide more efficient results of heat transfer when compared with common liquid. Therefore, the major novel aspect of the current analysis is to analyze the entropy production and thermal feature of the system in the presence of cross-diffusion, nonlinear radiation, endothermic/exothermic reaction, activation energy and dissipation effects. Slip factor is additionally considered to slowing down the nanomaterial velocity. Furthermore, the effects of Lorentz force and nonlinear mixed convection are accounted. The governing differential equations for considered nanofluids are first converted into dimensionless ODEs utilizing proper variables. The obtained system is then computed using NDsolve technique. The approximated results for different distributions are shown through curves and tables. The impact of dimensionless parameters is visualized on fluid velocity, temperature, concentration, Nusselt number, skin friction and entropy generation. It has been observed that velocity steps up with curvature, ratio of buoyancy, solutal mixed convection and thermal convection parameters but declines for upgrading slip parameter. The temperature step down by upgrading exothermic/endothermic parameter, Dufour number and Brownian diffusion parameter, thermophoretic parameter and radiation parameter. It is also noticed that the concentration of the nanofluid upsurges for increasing activation energy and soret number, but concentration minimizes for growing the temperature difference parameter. Numerical results show that the Nusselt number decays for rising Soret number, Dufour number, thermophoretic parameter and Brownian diffusion parameter but a reverse trend is seen for radiation parameter and activation energy. Also, skin friction coefficient declines by enhancing thermal convection parameter, solutal mixed convection parameter and slip parameter but upgrades for boosting buoyancy parameter.

Mixed Convection in a Casson Fluid Flow towards a Heated Shrinking Surface

In this paper, an extensive analysis of mixed convection effects on steady two-dimensional stagnation point flow of a Casson fluid over a heated horizontal sheet has been numerically investigated. The governing Navier-Stokes equations of the present problem are transformed into nonlinear ordinary differential equations by applying a similarity transformation. A numerical solution of the problem has been obtained by employing the linearization technique along with the finite difference discretization. The impact of the Casson fluid parameter, the thermo-radiative parameter, the mixed convection parameter, the slip parameter, and the Prandtl number on the fluid motion and temperature is studied through graphical data. The convection parameter, the slip parameter and the Casson fluid parameter tends to accelerate the flow. The temperature distribution is however reduced by the convection parameter, slip parameter, thermal radiation and the Prandtl number. This work is based on [25] in which micropolar fluid flow over a heated surface was investigated by using the homotopy analysis method. We have extended the problem by considering the combined impact of mixed convection and thermal radiation on the Casson fluid flow towards a heated shrinking sheet, by using a numerical method.

Coaxially swirled porous disks flow simultaneously induced by mixed convection with morphological effect of metallic/metallic oxide nanoparticles

This study focuses on the numerical modeling of coaxially swirling porous disk flow subject to the combined effects of mixed convection and chemical reactions. We conducted numerical investigations to analyze the morphologies of aluminum oxide (Al2O3) and copper (Cu) nanoparticles under the influence of magnetohydrodynamics. For the flow of hybrid nanofluids, we developed a model that considers the aggregate nanoparticle volume fraction based on single-phase simulation, along with the energy and mass transfer equations. The high-order, nonlinear, ordinary differential equations are obtained from the governing system of nonlinear partial differential equations via similarity transformation. The resulting system of ordinary differential equations is solved numerically by the Runge–Kutta technique and the shooting method. This is one of the most widely used numerical algorithms for solving differential equations in various fields, including physics, engineering, and computer science. This study investigated the impact of various nanoparticle shape factors (spherical, platelet and laminar) subject to relevant physical quantities and their corresponding distributions. Our findings indicate that aluminum oxide and copper (Al2O3-Cu/H2O) hybrid nanofluids exhibit significant improvements in heat transfer compared to other shape factors, particularly in laminar flow. Additionally, the injection/suction factor influences the contraction/expansion phenomenon, leading to noteworthy results concerning skin friction and the Nusselt number in the field of engineering. Moreover, the chemical reaction parameter demonstrates a remarkable influence on Sherwood’s number. The insights gained from this work hold potential benefits for the field of lubricant technology, as they contribute valuable knowledge regarding the behavior of hybrid nanofluids and their associated characteristics.

Non-similar solution of mixed convection flow of viscous fluid over curved stretching surface with viscous dissipation and entropy generation

The non-similar solution of a viscous fluid caused by a curved stretching surface with a convective boundary condition is considered in this article. The momentum equation is modified by considering the effects of MHD and mixed convection. The energy equation is modeled as subjected to joule heating and thermal radiation effects. The independent variable "s" is present in the Eckert and Grashof numbers, which is incompatible with dimensionless parameters. In this regard, a non-similar technique is used to tackle the problem. The non-similar approach has not been tried on a curved stretching surface. Moreover, the entropy rate is discussed under these observations. The non-similarity transformation is used to convert the modeled governing equations into dimensionless PDEs. A local non-similarity method is employed for the conversion of PDE’s into ODE’s, and the numerical solution of the resulting equations is obtained via bvp4c. The novelty of the problem is that when the thermal radiation, Hartman number, and Brinkman number increase, the entropy generation increases. The Bejan number increases with the Hartman number and thermal radiation, while the Brinkman number shows the opposite behavior in boundary layer. The nonlinear radiation parameter increases the thermal profile while reverse tends noticed for the entropy generation and Bejan number. The behaviors of velocity and temperature profiles are discussed graphically for the different parameters. Physical quantities like heat transfer rate and drag force are presented in tabular form.

Numerical investigation of chemically reacting jet flow of hybrid nanofluid under the significances of bio-active mixers and chemical reaction

Jet flows are employed in a variety of applications. It can be found in daily life as well as in agriculture, for example, jet flow assists with irrigation and harvest protection. The current problem is related to the study of energy and mass transference on the hybrid nanoliquid flow with mixed convection effect due to the vertical stretching surface conveying the cobalt ferrite CoFe2O4 and titanium dioxide TiO2 nanoparticles (NPs) with the base fluid water H2O. Further, the role of the chemical reaction, heat source/sink, and activation energy are investigated. By exploiting the idea of the modified Buongiorno model, the thermophoretic and Brownian diffusivity effects have discoursed on the existing flow behavior. The existing mathematical problem is framed with the application of the nonlinear higher-order PDEs. Higher-order PDEs of the mathematical model are changed into highly nonlinear ODEs by using the concepts of suitable similarity transformations. The modified higher-order nonlinear ODEs are cracked by manipulating the bvp4c technique in MATLAB. The impacts of the numerous physical flow parameters on the velocity, energy, and concentration are computed in graphical forms. Key findings from the present problem revealed that the velocity of the nanoliquid and hybrid nanofluid decreased due to greater nanoparticles volume fraction. Furthermore, the heat transportation is greater for mixed convection and thermophoresis parameter.

Mixed convection and thermal radiation effects on non-Newtonian nanofluid flow with peristalsis and Ohmic heating

Introduction: This investigation explores the heat and mass transfer properties of a non-Newtonian nanofluid containing graphene nano-powder and ethylene glycol during peristalsis. The rheological characteristics of the nanofluid are determined using the Carreau-Yasuda model, and various factors such as viscous dissipation, Lorentz force, Ohmic heating, and Hall effects are taken into account. Mixed convection and thermal radiation effects are also considered in the analysis, and the problem is mathematically described using the long wavelength and low Reynolds number approximations.Methods: The resulting nonlinear system is solved using numerical methods to obtain the solutions. The dominant effects of mixed convection and thermal radiation are given particular attention, while the influences of other parameters are discussed in relation to these dominant effects.Results and Discussion: The results demonstrate that increasing the Brinkman number, heat source, and thermal slip parameter leads to higher nanofluid temperatures. However, the heat transfer rate decreases with a higher Hall parameter. The velocity near the center of the channel increases for higher values of the concentration Grashof and Hall parameters. Furthermore, an increase in the Hall and Brownian motion parameters results in a higher concentration of nanoparticles. These findings have practical implications in various fields, including materials science, chemical engineering, and biomedical engineering.

Effects of thermophoresis and mixed convection on Carreau fluid flow with gold nanoparticles

Effects of thermophoresis and mixed convection on Carreau fluid flow with gold nanoparticles

Analysis of nonlinear radiative peristaltic transport of hyperbolic tangent nanomaterial with chemical reaction

In this research, we examine the mixed convection effects for peristaltic motion of tangent hyperbolic nanoliquid. On flexible channel walls, partial slip characteristics are applied. Influences of Ohmic heating and viscous dissipation are analyzed in the modeling. We evaluated the transportation of heat under nonlinear thermal radiation. The governing problem is first reduced into dimensionless form by using suitable transformations and then numerical technique is employed for the solution after utilizing small Reynolds number and large wavelength assumption. The problem is simulated employing the so-called Buongiorno’s formulation which includes the features of thermophoresis and random motion. In addition, a mass transport scheme is developed with first-order chemical reactions. The roles of sundry variables on velocity, coefficient of heat transfer, temperature and concentration are examined graphically. Velocity and temperature show similar behavior against thermal Grashof parameter. Concentration decreases for larger thermophoresis parameter. Heat transfer coefficient and temperature have decreasing effects against radiation parameter.

Variable thermo-physical properties of fluid flow along with exponential stretching; A chemical reaction study

Heat and mass transfer having variable fluid properties has wide range of applications in industrial and engineering processes.The transference of species arises in several processes like oil transport phenomenon, food processing and diffusion of assured medicines in blood (drug delivery). Current research deals with the mixed convection and radiation effects on flow of a non-Newtonian tangent hyperbolic fluid with variable thermo-physical properties and activation energy. Arrhenius kind of chemical reaction is taken along an exponentially stretchable surface. The main focus of the current exploration is to execute shear thinning tangent hyperbolic fluid past an exponentially stretchable surface under the influence of variable viscosity, mixed convection, thermal radiation and activation energy. Transformation approach is opted to attain the non-linear ODE's based on standard conservation laws of mass, linear momentum and energy. Numerical solutions of the governing problem are computed via the shooting technique. Characteristics of the parameters appearing in modeling like radiation parameter, variable viscosity parameter, mixed convection parameter, Williamson parameter, variable conductivity and diffusivity are comprehensively analyzed through graphical behavior.

Mixed convective-quadratic radiative MoS 2–SiO 2/H 2 O hybrid nanofluid flow over an exponentially shrinking permeable Riga surface with slip velocity and convective boundary conditions: Entropy and stability analysis

In this work, the flow of a hybrid Mo S 2 − Si O 2 /water nanofluid across a porous exponentially diminishing Riga surface with the effects of quadratic heat radiation is taken into account. We also considered the effects of mixed convection, slip velocity, and convective thermal boundary conditions. Before numerically solving the governing partial differential equations, the MATLAB function bvp4c was used to get a comprehensive description of all relevant flow characteristics. The ramifications of physical characteristics concerning fluid flow and thermal profile are investigated using graphs and tables. The primary objective of this study is to investigate the Nusselt number, skin friction coefficient, and entropy production. Using the second law of thermodynamics, the irreversibility factor is computed. For a given value of the mass suction parameter, the findings also indicate the occurrence of dual-nature solutions in the shrinking sheet area, with a stable upper solution branch and unstable bottom solution branch. In addition, the first solution produces a positive minimum eigenvalue, whereas the second solution produces a negative eigenvalue, showing the stability of the first solution. For heat transfer enhancement, the existence of quadratic thermal radiative parameter impacts is more advantageous. With a larger value for the modified Hartman number, the velocity field has expanded. Also, recent research demonstrates that raising the thermal Biot number enhances the thermal gradient. Increases in nanoparticle volume fraction and thermal radiation parameters lead to a commensurate rise in entropy production. Because of these findings, we can better regulate the temperature of various environments by controlling the flow of heat.

A numerical approach to the modeling of Thompson and Troian slip on magnetized flow of Al2O3–PAO nanolubricant over an inclined rotating disk

In automotive fluids, hydraulic, gear, and bearing oils, as well as in applications operating in extremely high or cold temperatures, PAO is widely employed. In present work, we have made an attempt to develop a mathematical model to discuss the flow of magnetized [Formula: see text] nanolubricant over an inclined rotating disk in Darcy-Forchheimer porous medium with Thompson and Troian slip at the boundary. The effects of mixed convection, nonlinear heat radiation, viscous dissipation, Joule heating, and non-uniform heat source/sink are also included in the modeling. We have solved the proposed model numerically with the help of MATLAB built-in bvp-4c method after metamorphosing the PDEs to ODEs. The enhancing values of inertial parameter and velocity slip parameter decrease the tangential and radial velocities of the nanolubricant. The temperature of the nanolubricant [Formula: see text] enhance significantly by strengthening the magnetic field, whereas radial and tangential velocities get retarded. The non-uniform heat source/sink parameters play a vital role in controlling heat transmission phenomenon. The increasing values of Eckert number, radiation parameter, and non-uniform heat generation parameters tend to increase the value of Nusselt number. The value of Nusselt number drops with rising values of Biot number and non-uniform heat sink parameters.