Convective Heat Conditions Research Articles

Variable density and heat generation impact on chemically reactive carreau nanofluid heat-mass transfer over stretching sheet with convective heat condition

The present study focuses on the physical significance of heat generation and chemical reaction on Carreau nanofluid with convective heat conditions. Heat transfer is characterized using convective boundary conditions. The governing partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) by using well define stream functions and similarity transformations. Using a shooting methodology, the Keller-box method with Newton Raphson scheme is used to elaborate the numerical solutions of physical phenomena. Utilizing a similar technique to find the impact of physical parameter such as the production of heat δ, the rate of reaction Λ, Biot numbers γ, Brownian motion variable Nb, the thermophoresis parameters Nt, the Weissenberg quantity We, Prandtl number Pr, and Lewis number Le on velocity profile, temperature profile and mass transmission profile are determined graphically. The skin-friction coefficient −f″(0), local Nusselt −θ′(0), and Sherwood numbers −ϕ′(0) are analyzed numerically. Increment in fluid velocity and slip temperature are depicted with high Biot number. Maximum magnitude of fluid temperature and fluid concentration function are depicted at high value of temperature dependent density. The magnitude of heat and mass transportation enhanced with maximum choice of Brownian motion.

Numerical simulation of a partially ionized Oldroyd-B nanofluid flow driven by two homocentric rotating disks with motile microorganisms

Nanofluids are assumed to be an excellent source of enhanced heat transfer with advanced thermophysical characteristics. Nanofluids are the backbone of the heating and cooling in the industrial processes. This research delves into the dynamics of a partially ionized Oldroyd-B nanofluid flowing between stretchable rotating disks. The study investigates heat transfer mechanisms incorporating a modified Fourier law and convective heat conditions. The viscoelastic fluid model presented here allows for the examination of relaxation and retardation times. Furthermore, the heat and mass transport of the Oldroyd-B nanofluid is characterized using a Buongiorno model, which considers thermophoresis and Brownian diffusion effects. Additionally, the study explores the impact of gyrotactic microorganisms in nanofluids, potentially enhancing environmental management strategies. The governing equations transform into dimensionless forms using Von Karman similarity variables. Numerical investigation of the anticipated model is conducted using the bvp4c scheme in MATLAB. The variation of different parameters in the dimensionless equations is illustrated through graphs and in tabulated format. The results indicate that increasing thermophoresis and Lewis numbers lead to a decrease in fluid concentration. Moreover, the temperature of the fluid rises at the lower disk and declines at the upper disk relative to the Biot number. The proposed model is validated through comparison with closely related published work.

Nonlinear convective transport of nanofluid over an inclined plate situated in a Darcy–Forchheimer porous medium with viscous dissipation and varying thermo-physical features

This article presents a theoretical analysis of the effects of varying thermo-physical properties, chemical reactions, and activation energy on the quadratic convective transport of nanofluids. The flow is created through an inclined plate in a Darcy–Forchheimer porous medium. The nanofluid model includes thermophoresis and Brownian motion to account for nanoparticle movement. The original flow equations are transformed using similarity transformations, and the resulting dimensionless equations are solved with a multi-domain spectral collocation approach. The effects of physical parameters on flow variables, heat and mass transfer coefficients are discussed. Comparisons between vertical and inclined plates reveal that inclination improves thermal performance but decreases velocity and engineering-related quantities. Fluctuating viscosity and nonlinear convection speed up fluid flow, whereas temperature rises with variable thermal conductivity and Biot number. Variable fluid properties, nonlinear convection, and convective heat conditions enhance heat transport coefficients. Activation energy boosts nanoparticle volume fraction profiles but decreases mass transport rates.

Impacts of nanoscaled metallic particles on the dynamics of ternary Newtonian nanofluid laminar flow through convectively heated and radiated surface

Heat transfer study influenced by various physical effects like thermal radiations, convective heat condition and thermal slip is one of the influential research domain specifically in applied thermal and chemical engineering. Therefore, the key purpose of this is to develop and discuss the heat performance of ternary nanofluid model including the effects of above mentioned parameters. The model is developed for laminar flow of ternary nanofluid about stagnation point over a cylinder's surface. Use of similarity transforms, properties of ternary nanofluids and ternary particles are exercised to obtain final model. Then, the RK-scheme is implemented for demonstration of the physical results and provided a detailed discussion. It is noticed that for λ=0.1,0.2,0.3,0.4, the ternary nanoliquid movement boosted and for λ=−0.1,−0.2,−0.3,−0.4 control the motion and MBLT (Momentum Boundary Layer Thickness) diminishes for saddle point case. Increasing the transient effects A1=0.05,0.10,0.15,0.20 causes quite rapid movement of the fluid molecules. Further, it is observed that thermal slip (α1=0.1,0.2,0.3,0.4), surface convection Bi=0.1,0.2,0.3,0.4 and thermal radiations are good physical aspects to enhance the heat transfer. Also, decrease in thermal boundary layer is observed. For composite φ=2.0%, density increases as 105 %(nano), 129 %(hybrid), 145 %(ternary), dynamic viscosity 105.18 %(nano), 113.503 %(hybrid), 122.483 %(ternary), thermal conductivity 106 %(nano), 115.5 %(hybrid), 131.71 %(ternary) and heat capacity diminishes.

Primitive and gravity modulation of periodical heat transfer along magnetic-driven porous cone with thermal conductivity and surface heat flux

The significant goal of present problem is to evaluate oscillating frequency and amplitude in heat and magnetic flux with thermal conductivity and heat flux effects across magnetized porous cone under lower gravitational region. To maintain heat transport efficiency, the thermal conductivity of conducting fluid is assumed as temperature dependent. The magnetic-driven cone is placed in lower gravitational region. To improve the heating rate across the magnetic-driven porous cone, the convective heating conditions are applied. The implications of thermal conductivity, surface heat flux, and reduced gravity on the periodic behavior of convective heat transfer characteristics of conducting fluid across porous gravity-driven cone is the novelty of this research. Using the appropriate non-dimensional variables, the model's nonlinear governing partial differential has been converted into a dimensionless form. The proposed model is solved later with the help of finite difference approach. The dimensionless form of the equations is reduced to the convenient form for numerical algorithm. The influence of adjusting parameters, such as thermal conductivity parameter ζ, reduced gravity parameter Rg, Biot number Bi, Prandtl number Pr, mixed convection parameter λ, porosity parameter Ω, magnetic prandtl number γ and some others stationary parameters has been highlighted. By using FORTRAN tool, the numerical outcomes are explored in graphs and tabular form. It is depicted that magnetic field enhances as Biot number decreases because magnetic field insulates the excessive heating across the magnetic-driven porous cone. It is noticed that significant amplitude in fluid velocity is noticed with prominent changes as reduced gravity increases. It is concluded that fluctuations in heat transport increases as parameter γ decreases under thermal conductivity because magnetic material insulates the extreme heat across the porous cone. The recent thermal conductivity and lowered gravity problem is significant in the fields of radioactive waste, cooling electronic components, storing nuclear, catalysts, heat exchangers, the underground storage of radioactive or nonnuclear materials, aircrafts and space vehicles.

Triple-Diffusive Bioconvection Flow of Sutterby Nanofluid Over an Oscillatory Stretchable Surface Immersed in a Darcy-Forchheimer Porous Medium

To respond to the demands of modern technological processes, the employment of nanofluids to maximize energy efficiency has been a topic of interest to many scientists. The stability of such nanofluids can be appropriately enhanced with the use of gyrotactic microorganisms. In the current framework, we inspect the triple-diffusive bioconvection flow of electro-magnetized Sutterby nanofluid via an oscillatory stretchable surface with Brownian diffusion of both nanoparticles and microorganisms, thermophoresis, buoyancy, and inertial forces. With the utilization of acceptable dimensionless variables, the governed flow equations are first metamorphosed into non-dimensional form, and solutions of the resulting equations are computed using the overlapping grid spectral collocation scheme. The rationale for choosing this numerical approach is provided by computing residual errors and condition numbers. The significance of physical parameters on the quantities of engineering interest and flow profiles is discussed. The main results include that reduced surface shear stress and minimal oscillatory nature of velocity are achieved with the inclusion of porous media, inertial forces, bioconvection, and nanofluid buoyancy forces. Temperature and rate of heat transfer are upsurged with the existence of variable thermal conductivity, nonlinear radiation, and convective heat conditions, which advocate that such features promote superior heat transport within the Sutterby working fluid. Growth in solutal Dufour Lewis number increases solutal concentration while reducing solutal-mass transfer rate. Improvement in microbial Brownian diffusion parameter causes enhancement in the rate of motile microorganisms transfer and reduction in the concentration of gyrotactic microorganisms. This implies that the random motion of motile microorganisms plays a prominent role in the dynamics of microorganisms.

Numerical heat featuring in Blasius/Sakiadis flow of advanced nanofluid under dissipation and convective heat condition effects

AbstractThe study of advanced nanofluids termed as Tetra nanofluid is of potential interest now a days. These fluids are upgraded generation of conventional nano to ternary hybrid nanofluids with outstanding characteristics. Applications of this class frequently occur in applied thermal engineering, nano‐lubrication, chemo‐therapy, chemical engineering, oil paint industry, coolant of nuclear plant and many other applied research areas. This study concerns with the development of innovative thermophysical rules for Tetra Hybrid nanofluid and their utilization in advanced heat transfer model. The governing laws updated through addition of thermal condition, dissipation effects, thermal radiations and upgraded nanofluid properties. Finally, the Blasius and Sakiadis model achieved and analyzed the heat transfer trends through numerical technique. Keen analysis of the drawn results show that Blasius model has much ability to transfer the heat than Sakiadis model. Induction of thermal radiations, dissipation effects and thermal convective condition is like a catalysis in the study of advanced tetra nanofluid model and boosts the temperature.

Microwave Inhibition of the Hydrogenation of CO2 for Methane Formation

The complex equilibria associated with the hydrogenation of CO2 to form valuable products are of considerable interest for the remediation of CO2. Due to the potential usefulness of these reactions, alternative methods of driving them more favorably using alternative energy sources, such as microwave radiation, are also of interest. We report here a study of the methanation reaction that yields CH4, which was studied under microwave and conventional convective heating conditions. An essential part of the science that arises from such studies is characterizing the microwave-specific effects on the reaction. From the determined equilibrium constants, we found that microwave radiation strongly inhibited the formation of CH4. The effective thermodynamic parameters obtained from a van’t Hoff plot reflect this inhibition. The enthalpy under microwave conditions is −38.63 kJ/mol, compared to −180.02 kJ/mol under conventional heating methods. Similarly, the free energy across the temperature range is less negative, suggesting a decrease in spontaneity under microwave conditions. We also observed a significant difference in the entropy, with entropy of −52 J/mol under microwave conditions and −206 J/mol under conventional conditions. This is consistent with prior observations that microwaves do not accelerate exothermic reactions. As discussed, this difference may arise from the microwave-driven dissociation of the reactant before CH4 bonds are made. Analysis of this system is of interest in understanding how the microwave inhibits the formation of the products of exothermic reactions. These results are of significance for understanding the broad area of microwave driven heterogeneous catalysis.

Corrigendum to “Thermal Transport in Radiative Nanofluids by Considering the Influence of Convective Heat Condition”

Corrigendum to “Thermal Transport in Radiative Nanofluids by Considering the Influence of Convective Heat Condition”

Thermal Circuit Models of Microstrip Lines Based on Precise Heat Spreading Angles and Convection Boundary Conditions

In this paper, the equivalent thermal circuits of microstrip lines are proposed based on the equivalent heat spreading angle (ESA) model and convection boundary conditions. Unlike the conventional constant-angle assumption, the ESAs corresponding to the situations of conductor and dielectric losses of microstrip lines are determined precisely by means of the modified parallel-plate model, which are associated with the geometry and material of the microstrip lines. Further, different kinds of boundary conditions are considered in the thermal circuit models, especially the impact of heat convection condition which matters in realistic situations. In addition, the thermal circuit models are extended to the case of coupled microstrip lines. The calculated results of the proposed model agree well with those simulated by the multiphysics solver.

Analysis of heat transfer phenomenon in hydromagnetic micropolar nanoliquid over a vertical stretching material featuring convective and isothermal heating conditions

This article evaluates the heat transfer mechanism in an incompressible hydromagnetic micropolar nanofluid enclosed in a two-dimensional vertically stretchable material surface in a porous device. In the current study, the developed model features the significant contributions of nonlinear radiative flux, viscous dissipation, Brownian movement together with thermophoresis effects in the transport region. An approach of similarity transformations is employed to transmute the transport equations from partial into ordinary differential equations. The translated equations are then integrated numerically via Runge–Kutta Fehlberg scheme plus shooting technique. From the analysis, it is found that there is an improvement in the mechanism of heat transfer for large magnitude of temperature ratio and radiation parameters due to the application of Convective Heating Condition (CHC) whereas the case of Isothermal Wall Condition (IWC) reveals an opposite direction for these parameters. Besides, an improvement in the magnitudes of the material micropolar term, Eckert number together with thermophoresis and Brownian movement parameters creates a decline in the surface heat transfer for both heating conditions.

Neural network method for quadratic radiation and quadratic convection unsteady flow of Sutterby nanofluid past a rotating sphere

In this study, the heat relocation properties of quadratic thermal radiation and quadratic convective unsteady stagnation point flow of electro-magnetic Sutterby nanofluid past a spinning sphere under zero mass flux and convective heating conditions are investigated. The governing equations are developed and expressed as partial differential equations, which are afterwards transformed into ordinary differential equations by applying similarity conversion. In the investigation, the JAX library in Python is employed with the numerical approach to artificial neural networks. It is investigated to what extent physical characteristics affect primary and secondary velocity, temperature, and concentration fields. The results demonstrate that due to increasing unsteadiness, Sutterby fluid, and magnetic field parameters, the flow of Sutterby nanofluid in the flow zone accelerates in the primary (x-direction) and slows down in the rotational (z-direction). The outcome also shows that an increase in the quadratic radiation parameter, the magnetic field constraint, and the electric field constraint induce increases in the temperature distribution of the Sutterby nanofluid. The study also shows that the concentration of nanoparticles decreases with increasing Lewis numbers and unsteadiness parameter values. Additionally, a graph illustrating the mean square error is investigated and provided.

Importance of exponentially falling variability in heat generation on chemically reactive von kármán nanofluid flows subjected to a radial magnetic field and controlled locally by zero mass flux and convective heating conditions: A differential quadrature analysis

Owing to the various physical aspects of nanofluids as thermally enhanced working fluids and the significance of swirling flows in rheological devices as well as in the spin coating and lubrication applications, the current comprehensive examination aimed to explore the important features of spinning flows of chemically reactive Newtonian nanofluids over a uniformly revolving disk in the existence of a radially applied magnetic field along with an exponentially decaying space-dependent heat source, in the case where the disk surface is heated convectively and unaffected by the vertical nanoparticles’ mass flux. Based on feasible boundary layer approximations and Buongiorno’s nanofluid formulation, the leading coupled differential equations are stated properly in the sense of Arrhenius’s and Von Kármán’s approaches. By employing an advanced generalized differential quadrature algorithm, the obtained boundary layer equations are handled numerically with a higher order of accuracy to generate adequate graphical and tabular illustrations for the different values of the influencing flow parameters. As findings, the graphical results confirm that the nanofluid motion decelerates meaningfully thanks to the resistive magnetic influence. A significant thermal amelioration can be achieved by strengthening the magnetic impact, the generation of heat, the thermal convective process, and the thermophoresis mechanism. Moreover, it is found that the thermo-migration of nanoparticles can be reinforced more via the intensification in the convective process, the thermo-migration of nanoparticles, and the activation energy.

Hydrothermal and mass impacts of azimuthal and transverse components of Lorentz forces on reacting Von Kármán nanofluid flows considering zero mass flux and convective heating conditions

An inclusive examination has been carried out numerically to explore the multiple physical prominences of steady MHD Von Kármán's flows of chemically reacting nanofluids that can be occurred over a rotating disk in the presence of a radially applied magnetic field, in the case where the disk surface is impermeable and heated convectively, in which the vertical nanoparticles’ mass flux has vanished practically. By applying the revised Buongiorno's formulation and Von Kármán's approach, the foremost conservation equations are derived properly in the context of the boundary layer theory. By applying an efficient differential quadrature algorithm, the boundary layer equations are treated numerically to generate accurate outcomes. As upshots, it is found that the nanofluid flow slows down meaningfully with the increase in the magnetic parameter. Significant enrichment in the temperature distribution and wall nanoparticles’ molar concentration can be achieved by mounting the magnetic parameter, the Schmidt number, and the chemical reaction parameter, whereas, the Prandtl number shows a reverse trend. It bears mentioning here that the convective heating reinforces the occurrence of the thermophoresis process.

Heat transfer inspection in [(ZnO-MWCNTs)/water-EG(50:50)]hnf with thermal radiation ray and convective condition over a Riga surface

The composition of hybrid nanoparticles in the base solvent is a way to improve the thermal efficiency of regular liquids which makes them more effective to cope with the heat transport problems faced by the modern technological world. Enhanced heat transfer in hybrid nanofluids opened the barrier towards applied thermal engineering, mechanical and chemical engineering regarding heat transfer. Therefore, this research is conducted to examine the improved thermal efficiency of [(ZnO-MWCNTs)/water-EG (50:50)]hnf and [(ZnO)/water-EG (50:50)]nf over a Riga surface; similarity transforms and hybrid nanoliquid correlations exercised to achieve the model. The constitutive model was modified by inducing thermal radiation effects and convective heat conditions. A numerical scheme is utilized as a mathematical tool and furnished the results for velocity gradient, thermal behavior and shear stresses under the physical constraints that appeared during the research. The results exposed that induction of novel thermal radiations (Rd) is a prime source to improve heat capability of [(ZnO-MWCNTs)/water-EG(50:50)]hnf. Further, an outstanding improvement in the temperature of [(ZnO-MWCNTs)/water-EG(50:50)]hnf was achieved due to convective heat conditions. As Bi number (due to the convectively heated surface) involves thermal conductivity of the surface materials, extra heat transferred from the surface material to the fluid which significantly contributed to the heat transfer mechanism of [(ZnO-MWCNTs)/water-EG(50:50)]hnf.

Study of Baffles Arrangement Influence on the Natural Convection into a Heated Square Channel

The present experimental paper is officiated to study the heat characteristics and performance of air flow through a square cross-sectional heated channel under natural heat convection conditions. The influence of baffles arrangement and perforated baffles on the rate of heat transfer through a channel are studied. Four cases of a heated channels are studied, one is a plain channel and other three channels with a baffle namely, three inline baffles, three staggered baffles and three staggered perforated baffles arrangements. The outer tested channels surfaces are electrically heated with a constant surface heat flux condition. All tested channels are fabricated by cold forming with constant dimensions using aluminum plate has thickness of 1.0 mm. The heat performance is assessed for all tested channels. The results of present paper are approved than the available data in the previous paper and a good convergence are noticed. Obtained experimental results appear that a three staggered perforated baffles arrangement is a best selection as it improves heat transfer rate in expression of Nusselt number, it higher about 22% to 27% than that the plain channel for same conditions.

Investigation of comparative 3D nonlinear radiative heat transfer in [(MnZnFe2O4–NiZnFe2O4)/C8H18]hnf and C8H18 under the surface permeability with modified slip effects

The progress in new inventions in the modern technological world demands outstanding heat transport. Unfortunately, common solvents are unable to produce such desired amount of heat which compelled the scientists and researchers towards the development of new heat transfer fluids (Nanofluids). Therefore, the study of C8H[Formula: see text] with hybridization of [(MnZnFe2O4–NiZnFe2O[Formula: see text]][Formula: see text] under novel effects of thermal radiations and convective heat conditions over a slippery permeable surface is organized. The modified thermophysical correlations for hybrid nanofluids were used and successfully achieved the modified heat transfer model. After numerical investigation, the results were plotted under varying parameters and provided for comprehensive discussion. The results revealed faster fluid motion and [Formula: see text] is dominant. The velocities drop significantly due to the permeability of the surface. Further, thermal radiations potentially boost heat transfer by providing extra energy to fluid particles. The temperature coefficient [Formula: see text] due to nonlinear thermal radiations also indicated faster heat transport.

Thermal efficiency in hybrid (Al2O3-CuO/H2O) and ternary hybrid nanofluids (Al2O3-CuO-Cu/H2O) by considering the novel effects of imposed magnetic field and convective heat condition

Comparative heat transfer analysis in conventional (Al2O3-CuO/H2O)hnf and modified hybrid nanofluid known as ternary hybrid nanofluid (Al2O3-CuO-Cu/H2O)mhnf is one of the potential topics of interest and is the demand of modern technological world to cope with the heat transfer problems faced by the industrialists and engineers. Therefore, the study is organized for hybrid and tri-hybrid nanofluids for their thermal storage. To improve thermal energy storage in the above-mentioned fluids, novel effects of a uniform magnetic field, convective heat transfer mode, and newly developed empirical correlations are used to synthesize tri-hybrid nanofluids. The comparative analysis under various physical constraints reveals that tri-hybrid nanoliquids have ultra-high thermal efficiency than conventional nanoliquids. Therefore, these fluids are very beneficial for industrial uses more specifically for purification purposes or where ultra-high heat transfer is required to accomplish the process.

Characterization of Cross nanofluid based on infinite shear rate viscosity with inclination of magnetic dipole over a three‐dimensional bidirectional stretching sheet

AbstractFluid viscosity manages several engineering processes and keeps its leading role in lubrication models, biological models, polymer processes, melt solutions, colloidal suspensions, and mayonnaise. The cross viscosity model is the most appropriate model, which interprets the key features of non‐Newtonian fluids in the region of shear‐thinning/thickening when very high and very low shear rates are applied. This article focuses on the mathematical model of three‐dimensional Cross nanofluid and interprets its aspect of infinite shear rate of viscosity over the expanding sheet. Velocity is studied through placing inclined magnetic dipole effect, transportation phenomenon is brought by considering the radiation effects, heat generation and chemical process is engaged for concentration of nanoparticles. The geometry of this mathematical model is expanding the stretching sheet with velocity slip, and convective heat conditions are associated. Similarity variables are being utilized for conversion dimensional mathematical model into nondimensional one. For the pursuit of numerical solution of the system of nondimensional mathematical model, the numerical technique Bvp4c is utilized. Furthermore, Matlab graphs and statistical analysis for all physical parameters and physical quantities are shown in the result and debate section. Due to inclination of angle Lorentz force producing in increasing manner, hence flow is opposed, and velocity of fluid is dropped for () and () and for increasing value of n index, the velocity of fluid flow is decreasing.

Numerical thermal featuring in γAl2O3-C2H6O2 nanofluid under the influence of thermal radiation and convective heat condition by inducing novel effects of effective Prandtl number model (EPNM)

The investigation of thermal transport in the nanofluid attained much interest of the researchers due to their extensive applications in automobile, mechanical engineering, radiators, aerodynamics, and many other industries. Therefore, a nanofluid model is developed for γAl2O3-C2H6O2 by incorporating the novel effects of Effective Prandtl Number Model (EPNM), thermal radiations, and convective heat condition. The model discussed numerically and furnished the results against the governing flow quantities. It is examined that the nanofluid velocity alters significantly due to combined convection and stretching parameter. Induction of thermal radiation in the model significantly contributed in the temperature of nanofluids and high temperature is observed by strengthen thermal radiation (Rd) parameter. Further, convection from the surface (convective heat condition) provided extra energy to the fluid particles which boosts the temperature of γAl2O3-C2H6O2. The comparison of nanofluid (γAl2O3-C2H6O2) temperature with base fluid (C2H6O2) revealed that γAl2O3-C2H6O2 has high temperature and would be fruitful for future industrial applications. Moreover, the study is validated with previously reported literature and found reliability of the study.