Linear Function Of Temperature Research Articles

Thermosolutal convection in a Brinkman–Darcy–Kelvin–Voigt fluid with a bidisperse porous medium

A model for thermosolutal convection of a category of viscoelastic fluids in a bidisperse porous medium is comprehensively investigated. The Brinkman model is employed in macropores, whereas the Darcy model is utilized in micropores. In the momentum equations, the densities are considered a linear function of temperature and concentration. The concentration of solutes at equilibrium is assumed to be a linear function of temperature. There are two situations considered, where we have study systems that are heated below and salted above and heated and salted below. The fluids are of the Kelvin–Voigt type. The critical Rayleigh numbers for linear instability and nonlinear stability are computed.

Aspects of chemical reaction and mixed convection in ternary hybrid nanofluid with Marangoni convection and heat source

The proposed study examines the effect of inclined magnetic field on a ternary hybrid nanofluid flow that is axisymmetric thermo-solutal Marangoni convective over an infinite disc. Some well-known uses of Marangoni convection include semiconductor production, atomic reactors, crystal growth, fine art mechanisms, melting, thin-film stretching and welding processes. The non-uniform heat generation and viscous dissipation are taken into account. The thermal conductivity and diffusivity coefficient are presumed to vary inversely with linear function of temperature and concentration. The ternary hybrid nanofluid, which consists of silicon dioxide ([Formula: see text]), iron oxide ([Formula: see text]), molybdenum disulfide ([Formula: see text]) and ethylene glycol as base liquid, undergoes an energy transition to improve heat transfer. The system of PDEs is transformed into nonlinear ordinary differential equations (ODEs) by using the appropriate transformations. Using the BVP4C method, this problem is numerically solved. The heat and mass phenomena rates on flow behavior are investigated using tables and graphs to address the impact of several physical and flow parameters on velocity, concentration, and thermal profiles. By increasing the Marangoni convection parameter, the surface tension gradient gets stronger, leading to more efficient heat and mass transfer inside the liquid as well as stronger induced flows. As the temperature and concentration profiles decrease, the outcome is a more consistent dispersion of these properties throughout the liquid.

Developing computational methods of heat flow using bioheat equation enhancing skin thermal modeling efficiency

PurposeThe main objective of this paper is to investigate the response of human skin to an intense temperature drop at the surface. In addition, this paper aims to evaluate the efficiency of finite difference and finite volume methods in solving the highly nonlinear form of Pennes’ bioheat equation.Design/methodology/approachOne-dimensional linear and nonlinear forms of Pennes’ bioheat equation with uniform grids were used to study the behavior of human skin. The specific heat capacity, thermal conductivity and blood perfusion rate were assumed to be linear functions of temperature. The nonlinear form of the bioheat equation was solved using the Newton linearization method for the finite difference method and the Picard linearization method for the finite volume method. The algorithms were validated by comparing the results from both methods.FindingsThe study demonstrated the capacity of both finite difference and finite volume methods to solve the one-dimensional and highly nonlinear form of the bioheat equation. The investigation of human skin’s thermal behavior indicated that thermal conductivity and blood perfusion rate are the most effective properties in mitigating a surface temperature drop, while specific heat capacity has a lesser impact and can be considered constant.Originality/valueThis paper modeled the transient heat distribution within human skin in a one-dimensional manner, using temperate-dependent physical properties. The nonlinear equation was solved with two numerical methods to ensure the validity of the results, despite the complexity of the formulation. The findings of this study can help in understanding the behavior of human skin under extreme temperature conditions, which can be beneficial in various fields, including medical and engineering.

Numerical study for bioconvection in Marangoni convective flow of Cross nanofluid with convective boundary conditions

The current study investigates incompressible, MHD flow of Cross nanofluid containing of gyrotactic microorganisms and thermophoretic particle deposition over a sheet with activation energy and variable thermal conductivity. The variable characteristic of thermal conductivity is considered as a linear function of temperature. The present study’s insights can optimize the design of nanofluid-based systems, enhance drug delivery methods, improve environmental monitoring, refine materials engineering, advance microfluidics for diagnostics, boost renewable energy technologies, and upgrade electronics cooling solutions. Moreover, this study contribution to scientific understanding will catalyze further research across disciplines, fostering innovation and progress. Cross nanofluid containing iron oxide [Formula: see text] nanoparticles, and based fluid ethylene glycol ([Formula: see text] is used. In the current study, distributions of concentration, temperature, mass, microorganisms, and flow are examined in the presence of nanofluid while also accounting for thermophoretic particle deposition and a heat source. The proposed flow equations are transmuted into ODEs by employing the suitable similarity variables. RKF-45th approach is used to evaluate the reduced equations. Graphs are used to determine the effects of important factors on thermal, microorganism, concentration, and flow profiles. With a rise in the Marangoni ratio parameter, the velocity distribution is enhanced, whereas the temperature distribution exhibit inverse behavior.

Significance of binary chemical reaction with activation energy in magneto-bioconvection flow of a Powell Eyring nanofluid past an inclined stretching sheet by considering temperature-dependent viscosity and thermal conductivity

ABSTRACT In this paper, an unsteady magneto-bioconvection flow of Powell Eyring nanofluid over an inclined stretching sheet in the presence of variable viscosity and thermal conductivity with multiple slip effects has been investigated numerically. The binary chemical reaction with activation energy, viscous dissipation and nonlinear thermal radiation effects are included in this study. The fluid viscosity and the thermal conductivity are assumed to be a linear function of temperature. The basic governing equations are solved numerically by the Runge-Kutta Felhberg method after using similarity transformation. The impact of bioconvection and important physical parameters on profiles of velocity and temperature of nanofluid and nanoparticles concentration, the density of motile microorganisms are analyzed graphically. Findings reveal that the velocity profile decreased by increasing the Powell Eyring fluid parameter values, whereas the temperature distribution depicts the opposite trend. The temperature profile increased with an increment of thermal conductivity parameter, whereas the opposite trends are found for Eckert number. The trend of the graph of temperature profile and nanoparticle concentration profile declined with an increment of the temperature slip parameter. Also, the nanoparticle concentration profile and density of microorganism profile decreased with an increment of activation energy parameter and chemical reaction parameter. The scope of the present investigation can be related to the advanced nanomechanical bioconvection energy conversion devices and bio-nanocoolant systems, among other relevant things.

Photo-thermoelastic wave propagation with changing thermal conductivity on excited pulsed laser nanoscale microelongated semiconductor material

Indroduction: The novel model of a non-local elastic semiconductor material that is microelongated is created. The process of photothermal transfer is responsible for the stimulation of the material. Photo-thermoelastic theories are used when the thermal conductivity is changed for the non-local medium. Under the influence of laser pulses, the effective framework describes the nanoscale microelongation instance as well as the interference between the photo-thermoelastic propagation waves in the non-local medium. It is possible to think of thermal conductivity as a linear function of temperature when electronic and thermoelastic deformation mechanisms are described. Two-dimensional deformation (2D) is used to extract the main fields, which obtained in non-dimension.Methods: Harmonic wave analysis, which is described by the normal mode, has been used to convert the basic equations into non-homogeneous higher-order ordinary differential equations. Applying a small subset of the possible non-local semiconductor surface conditions leads to exhaustive solutions.Result and Discussion: The outcomes of numerical simulations for silicon (Si) are graphically shown. There are comparisons made and explanations given for the investigated physical factors like their thermal conductivity, laser pulses and microelongation parameters.

Vieta-Lucas Collocation Technique for Examination of the Flow of Casson Fluid over a Slippery Stretching Sheet Which Is Impacted by Thermal Slip, Ohmic Dissipation, and Variable Thermal Conductivity

This work aimed to present the influence of the magnetic field and Ohmic dissipation on the non-Newtonian Casson fluid on a vertical stretched sheet to numerically solve the problem. Here, the variable thermal conductivity is taken as a linear function of temperature. Electric fields, thermal slip, and viscous dissipation effects are taken into consideration. A collection of physical conditions on the sheet’s enclosing wall and the momentum and heat transport processes are expressed as partial differential equations (PDEs). Some of the similarity transformations are used to convert the collection of PDE into a system of ordinary differential equations. This system is numerically treated by implementing the Vieta-Lucas spectral collocation method. Some observations are made for the investigation of method convergence. The effect of some different parameters on the velocity and temperature profiles is graphically represented. Additionally, this area of study has significant practical applications in a variety of industries, including paper production, thermal power generation, nuclear reactors, cooling of metallic sheets, glass fiber, and lubrication.

The effect of temperature and vulcanisation time on the thermal and mechanical properties of rubber used in tires

ABSTRACT The thermal and mechanical properties of rubber used in tires were measured experimentally. The effect of temperature on the thermal properties and the effect of vulcanisation time on the mechanical properties are analyzed. The specific heat capacity and thermal conductivity both increase with increasing temperature, and the specific heat capacity and thermal conductivity are approximated as linear functions of temperature. The tensile strength, elongation at break and abrasion properties of vulcanizate are significantly affected by the vulcanisation time. As the vulcanisation time increases, the tensile strength first increases and then decreases, and the elongation at break changes with the vulcanisation time on the contrary. The wear volume of tread rubber first decreases and then increases with the increase of vulcanisation time. At the positive vulcanisation time, the tensile strength of the vulcanizate reached the maximum value, while the elongation at break and wear volume reached the minimum value.

Microtemperature photothermal excitation of semiconductor material influenced by electromagnetic Hall current and variable thermal conductivity

The effects of fluctuating thermal conductivity and Hall current in an elastic semiconductor material is studied. When the thermal conductivity is assumed to be a linear function of temperature, the medium is exposed to a very high magnetic field. It is investigated how the elastic medium's microstructure and the external magnetic field interact. The photothermal excitation mechanisms are the setting in which the microtemperature effect is produced. For a semiconductor rod, the overlapping of elastic, magnetic, plasma, and thermal waves is addressed in one dimension (1D). The governing equations of the microtemperature field are solved using the Laplace transform and a specific map in 1D. Analytically and in the physical time domain, the principal physical quantities in this phenomenon have their exact solutions. In the framework of the recombination plasma process, some mechanical boundary conditions with thermal shock are applied at the free surface of the elastic medium. To acquire the complete solutions of the major physical quantities, the Laplace transform is inverted and employed as a numerical method. Under the influence of fluctuating thermal conductivity in Hall current and the microtemperature effect, certain comparisons are done for the physical values that are shown graphically and theoretically addressed.

THERMOSOLUTAL CONVECTION IN A BIDISPERSE POROUS MEDIUM WITH CHEMICAL REACTION EFFECT AND RELATIVELY LARGE MACROPORES

The model of double diffusive convection in a bidisperse porous medium was examined. Brinkman effects and slip were allowed to be used in macropores. In the micropores, only the Darcy effects are held. In equilibrium, the concentration of solutes is thought to be a linear function of temperature. We performed both a linear and a nonlinear stability analysis, with a particular emphasis on the impact of slip boundary conditions on the system's instability and stability. After deciding when the instability started, we determined the critical Rayleigh number as a function of the slip coefficient. Numerical findings for stability/instability thresholds were also presented.

Graded Longitudinal Fins Having Spatially Varying Temperature-Dependent Thermophysical Properties

This paper reports transient responses of graded longitudinal fins subject to step change in base temperature and base heat flux wherein the graded fin materials are theorized to have spatial- and temperature-dependent thermal conductivity. Microstructure variations in graded materials (GMs) are addressed by axially varying the thermal conductivity; because GMs are potentially high-temperature application materials, consequently, thermal conductivity and heat generation are, respectively, assumed as polynomial and linear functions of temperature. Additionally, most of the applicable pragmatic fluid regimes are accounted for using the power law convection coefficient. The numerical solution of a typical nonlinear governing differential equation is obtained by using a particle tracking-based method called the lattice Boltzmann method (LBM). The LBM is a mesoscopic-based simulation method centered around the principles of kinetic theory and statistical mechanics. The LBM formulation accompanied with the in-house MATLAB code of the aforesaid problem with varying parameters is reported; also, it is validated with a previously available solution. The foregoing analysis is carried out to enhance the performance of a fin by using the superior thermomechanical property of graded materials. Furthermore, the inclusion of temperature-dependent thermophysical properties and heat generation will provide more accurate design data. The reported graph reveals that, even though a linear GM fin tip possesses thermal conductivity that is 25% less in magnitude in comparison to the Type-II homogeneous material (HM-2), the GM fin always yields a higher fin tip temperature because of grading. In addition, the tip temperature deficits between GMs and HM-2 proportionally increase from 0.4 to 2.1% for values of increasing from 0.1 to 2.0, respectively, for step changes in temperature; whereas in the case of the step change base flux, the deficits increase from 8.72 to 12.1% for values of decreasing from 3.0 to 1.0, respectively.

Numerical investigation on steady natural convective flow past a perpendicular wavy surface with heat absorption/generation

The controlling of heat transport procedures through external energy source effects is one of the mainly significant problems in modern applied physical sciences. Major strong research in thermal sciences, mechanical engineering and including energy modeling, planning and energy supervisions, energy conservations, energy efficiencies, biomass and bio-energy, renewable energy, energy storage, energy in buildings. In the current existing paper, the consequences of thermal conductivity on temperature, this is inversely proportionally by the linear function of temperature on free convective movement of an incompressible viscous fluid through the heated uniform and vertical wavy surface is examined. Associated with boundary conditions, the governing boundary layer equations be translated into the non-dimensional structure for phenomenon by utilizing an appropriate transformation. In the domain of vertical plate that is flat, the resulting method of nonlinear partial differentiated equations are mapped and then numerically by applying the implicit finite difference technique with Keller-box technique. The rate of heat transfer, the skin friction coefficient, the isotherms and streamlines throughout the boundary layer are exhibited graphically.

Analysis of Reciprocal Thermal Conductivity on Free Convection Flow along a Wavy Vertical Surface

The effects of thermal conductivity which depend on temperature are conversely proportional with the linear function of temperature on free convective flow where the fluid is viscous and incompressible along a heated uniform and the vertical wavy surface has been examined in this study. The boundary layer equations with the associated boundary conditions that govern the flow are converted into a nondimensional form by using an appropriate transformation. In the domain of a vertical plate that is flat, the resulting method of nonlinear PDEs is mapped and then worked out numerically by applying the implicit central finite difference technique with Newton’s quasilinearization method, and the block Thomas algorithm is well known as the Keller-box method. The outputs are obtained in the terms of the heat transferring rate, the frictional coefficient of skin, the isotherms, and streamlines. The outcomes showed that the local heat transferring rate, the local skin friction coefficient, the temperature, and the velocity all are decreasing, and both the thermal layer of boundary and velocity become narrower with the rising values of reciprocal variation of temperature-dependent thermal conductivity. On the other hand, the friction coefficient of skin, the velocity, and the temperature decrease where the friction coefficient of skin and velocity decrease by 43% and 64%, respectively, but the heat transfer rate increases by 61% approximately, and both the boundary layer thermal and velocity become thinner when the Prandtl number increases.

Density and viscosity of Ni–Ti melts measured by an electrostatic levitation technique

Density and viscosity of Ni–Ti melts were measured under high-vacuum conditions using an electrostatic levitation technique. The density of Ni–Ti melts can be expressed as a linear function of temperature. The variation of viscosity of Ni–Ti melts with temperature can be reproduced by an Arrhenius function. The excess volume was obtained from the density results and is discussed using the thermodynamic functions of enthalpy of mixing and excess Gibbs energy. Viscosity shows a positive deviation from linear additivity. From comparison with theoretical models, the viscosity is roughly reproduced by Kozlov's model. The viscosity of Ni–Ti melts is possibly influenced by formation of clusters, which form based on congruently melting compounds.

BIO-MAGNETIC FLOW OF HEAT TRANSFER OVER MOVING HORIZONTAL PLATE BY THE PRESENCE OF VARIABLE VISCOSITY AND TEMPERATURE

This work aims at the investigation of 2D, steady, laminar, viscous, incompressible boundary layer and heat transfer flow of a biomagnetic fluid over a convectively heated moving horizontal plate in the presence of a magnetic dipole. It is assumed that the fluid viscosity is the inverse linear function of temperature and the temperature at the wall varies as power law function. The governing equations involve a system of coupled PDEs (momentum and energy equations) which are converted into a system of nonlinear ODEs by utilizing similarity transformations. The transformed ODEs along with the boundary conditions are then solved numerically by adopting a finite difference algorithm. The physical effects of the governing parameters (i.e., ferrohydrodynamic interaction parameter, buoyancy force parameter, viscosity-temperature parameter, wall parameter) on the flow fields along with the skin friction and heat transfer rate are presented. Verification of this work has been done by comparing former published results and acceptable agreement is found. It has been analyzed theoretically by using suitable transformations, that the ferrohydrodynamic interaction parameter, has a great enhancement effect on biomagnetic fluid rather than that on a regular fluid. It has been discovered that the inclusion of certain intensity of magnetic field along with the consideration of the variable viscosity and temperature, has significant effects on the flow and heat transfer mechanism. These outcomes could be of interest in medical as well as bioengineering implementations, like magnetic drug delivering in blood cells, separating RBCs (Red Blood Cells), controlling the flow of blood during surgeries and treating cancer by producing magnetic hyperthermia.

Effects of humidity and temperature on the non-linear elasticity of rocks

SUMMARY Small velocity changes, associated with the non-linear response of rocks within the Earth, have been measured from dense arrays of seismometers to observe crustal deformation, the influence of solar heating and in situ pore pressure changes. Characterization of the non-linear elastic response of rocks provides new insight into rock microstructure and possibly new ways to determine the presence and type of fluid in the pore space. We conducted a long-term experiment to understand the influence of humidity and temperature on the non-linear elastic properties (NEPs) of rocks. The relative velocity change (dv/v), a NEP, is computed from the time of flight delay caused by the presence of a superposed high amplitude ultrasonic signal in a sandstone sample within a controlled environmental chamber. Our phenomenological model for diffusion of humidity into the pore space fits the dv/v data exceptionally well, showing the dv/v is a linear function of humidity. We subtract the dv/v predicted by the humidity diffusion model from the measured dv/v to get a residual dv/v. This residual dv/v can be well fit by a temperature diffusion model in which the dv/v is a linear function of temperature. We suggest that dv/v is a sensitive indicator of moisture in pore spaces of rock and the temperature of the rock.

Effect Of Electric Field Modulation On Electroconvection In A Dielectric Fluid-Saturated Porous Medium

<p>The stability of a horizontal sparsely packed porous layer of a dielectric fluid heated from below is examined when the fluid layer is subjected to time-dependent electric field modulation. The dielectric constant is assumed to be a linear function of temperature. The regular perturbation method is used to find the critical Rayleigh number and the corresponding wavenumber for small amplitude electric field modulation. The stability of the system characterized by a correction Rayleigh number is computed as a function of thermal, electric, and porous parameters, and the frequency of electric field modulation. It is found that the onset of electro-convection can be delayed or advanced by the presence of these parameters. The effect of various parameters is found to be significant for moderate values of the frequency of electric field modulation. Some of the known results are recovered as special cases of the present study. The findings of the present study have possible implications in the control of electro-convection with a time-varying electric field.</p>

Thermal Response of a Thick Circular Plate With Internal Heat Sources in Time Fractional Frame

Present paper investigated the thermoelastic response of an axisymmetric two-dimensional time fractional thermoelastic problem. The order of the problem is 0   2 which occupy the space D{(x, y,z)R3 : 0r b, h z h}. Further, convection type boundaries with heating ( ) ( ) 1 0 Q t  r  r and ( ) ( ) 2 0 Q  t  r  r are applied on the both surfaces respectively, whereas plate is subjected to the action of internal heat is the linear function of temperature. Next, integral transformation techniques are used to calculate temperature, displacement and thermal stresses. The graphical method is used to analyze the properties of Aluminum.

Influence of variable thermal conductivity on thermal-plasma-elastic waves of excited microelongated semiconductor

A novel model is formulated of a microelongated semiconductor material. The material is excited in the context of photothermal transport processes. The photo-thermoelasticity theories are applied when the thermal conductivity of the microelongated semiconductor medium is changed. The novel model describes the microelongation case and the interference between the different propagation waves in the elastic medium. Thermal conductivity can be taken as a linear function of temperature during electronic and thermoelastic deformation processes. The dimensionless main fields are taken in a two-dimensional (2D) with maps converter. The harmonic wave method according to the normal mode analysis has been applied to convert the main equations to higher-order ordinary differential equations (ODE). Complete solutions are obtained by applying some conditions that are taken on the semiconductor surface. The results obtained for silicon (Si) are numerically simulated, with illustrations showing this. The comparisons are made and discussed for the main fields during the variable thermal conductivity and microelongation.

Heat and mass transfer study of ferrofluid flow between co-rotating stretchable disks with geothermal viscosity: HAM analysis

The investigation of ferrofluid flow in rotating disk systems has been increased due to the many engineering applications in rotating objects. Ferrofluids are greatly significant in sealing of rotating shafts in hard disk drives. For this reason, the ferrohydrodynamics flow, heat, and mass transfer characteristics of a fluorocarbon-based magnetic nanofluid (FC-72) between two coaxial rotating stretchable disks have been examined. Both lower and upper disks are stretchable, and the viscosity of magnetic nanofluid (MNF) is directly proportional to the linear function of depth and inversely proportional to the linear function of temperature. Moreover, the heat transfer process is carried out with the viscous dissipation effect. An approach of similarity transformation is used to convert the obtained fundamental equations into a non-dimensional system of equations. The semi-analytic homotopy analysis method is executed to obtain the convergent series solution of a non-dimensional system of equations. Mathematica package BVPh 2.0 based on HAM is applied to plot the solution of dimensionless differential equations. The behavior of influential parameters, namely, viscosity variation, rotation, ferrohydrodynamic interaction, radiation, Prandtl number, Eckert number, and Reynolds number, on the flow regimes are shown graphically. It is obtained that the magnitude of horizontal velocity reduced in the vicinity of lower disk for increasing value of viscosity parameter γ1. Fluid temperature magnitude and nanoparticle concentration are increasing functions of Reynolds number.