Presence Of Heat Transfer Research Articles

Exploring Unsteady Three-Dimensional Casson Fluid Flow through a Stretching Surface with Heat Source/Sink: A Numerical Investigation

This research aims to examine the effects of a heat source or sink and viscous dissipation on an MHD unsteady three-dimensional Casson fluid flow across a stretched sheet. Using similarity transformations, the governing partial differential equations are transformed into coupled ordinary differential equations, which are then solved numerically in Matlab. The numerical findings for several physical parameters that impact velocity and temperature profiles are described in tables and graphs. The interesting finding are recorded as follows: When the Magnetic parameter increases, the skin friction coefficient increases along x and z directions, but when the Casson parameter lowers, it decreases. The Nusselt number increases with the enhancement of viscous dissipation parameter and heat source or sink parameter. Understanding the behavior of non-Newtonian fluids in the presence of heat transfer is crucial in a number of domains, including chemical engineering, biomechanics, and material processing. These applications might benefit from this kind of study.

Peristaltic transport of diethylene glycol-based magnesium aluminate nanofluid under the effects of viscous dissipation and Hall current

ABSTRACT The fundamental importance of peristaltic phenomena in numerous biological systems, including dialysis, heart-lung machines, urine transportation, invertebrate locomotion, and the passage of gallbladder bile into the intestines, persuaded scientists to investigate the different aspects of it over the past few years. In addition, peristaltic pumping is an important consideration in industrial processes including, roller pumps used for the transport of sanitary materials, finger pumps, cell separation, and endoscopes. Keeping such inspirational applications in mind, the present investigation is dedicated to exploring the peristaltic transport of a Cross-magneto nanofluid through a curved geometry in the presence of heat transfer. The inspection of the heat transfer is conducted by utilizing variable viscosity and ohmic heating aspects. This study also retains the characteristics of viscous dissipation, heat generation/absorption, and thermal conductivity of nanofluids. Modeling of the 2D, incompressible Cross nanofluid with peristaltic movement is carried out using a curvilinear coordinate system. The basic equations of the problem are mPodeled in the light of physical laws and then simplified by adopting the lubrication theory. The solutions of the resulting nonlinear system are computed numerically. The outcomes of the related flow parameters on the nanofluid’s temperature, pressure gradient, velocity distribution, heat transfer, streamlines pattern, and stresses at the wall are discussed through graphs. The graphical results depict that the rates of heat transfer are augmented by increasing the curvature parameter, Hartmann number, and nanoparticles’ volume fraction while decreasing the Hall parameter and temperature-dependent viscosity parameter. Moreover, the nanofluid’s temperature increases by improving the values of the heat generation parameter, whereas it decreases for the Hall parameter. Furthermore, a reduction in the axial velocity occurs near the center of the channel, when Hartmann number attains higher values.

Magneto-hydrodynamic peristaltic flow of a Jeffery fluid in the presence of heat transfer through a porous medium in an asymmetric channel

In the present paper, the effects of magnetic field and heat transfer on the peristaltic flow of a Jeffery fluid through a porous medium in an asymmetric channel have been studied. The governing non-linear partial differential equations representing the flow model are transmuted into linear ones by employing the appropriate non-dimensional parameters under the assumption of long wavelength and low Reynolds number. Exact solutions are presented for the stream function, pressure gradient, and temperature. The frictional force and pressure rise are both computed using numerical integration. Using MATLAB R2023a software, a parametric analysis is performed, and the resulting data is represented graphically. For all physical quantities considered, numerical calculations were made and represented graphically. Trapping phenomena are discussed graphically. The obtained results can be applied to enhance pumping systems in engineering and gastrointestinal functions. This analysis permits body fluids such as blood and lymph to easily move inside the arteries and veins, allowing oxygen supply, waste elimination, and other necessary elements.

Visco-Elastic Oscillatory Flow in a Porous Channel with Heat Transfer in Presence of Magnetic Field

Visco-Elastic Oscillatory Flow in a Porous Channel with Heat Transfer in Presence of Magnetic Field

Effect of heat transfer on peristaltic flow of Newtonian fluid through eccentric cylinders

Heat transfer effect on peristaltic Newtonian flow in an annular region of eccentric cylinders is considered. An approximate solution for temperature and velocity is obtained using perturbation technique. For constant flow rate, the variation of pressure gradient and velocity with respect to several non-dimensional parameters is studied using graphical representation. It is seen in these graphs that velocity, pressure gradient and temperature enhance with raise in eccentricity and amplitude ratio. Heat diffuses with faster rate with depletion in area of cross section eccentric annulus through parameter inner cylinder radius. Also, velocity rises with increase in heat transfer parameters such as Grashof number and heat transfer co-efficient. Thus velocity of peristaltic flow in eccentric annulus enhances rapidly in presence of heat transfer compared to absence of heat transfer. A study of peristaltic flow in concentric annulus in presence of heat transfer is obtained analytically and compared with present study at eccentricity equal to zero, to validate the approximate solution. It is seen that flow rate increases more in case of eccentric annulus compared to concentric in presence of heat transfer. Present study has application in endoscope, which is important to diagnose problems in internal organs. Also, the variation of pressure gradient helps to maintain flow rate which is essential during insertion of catheter into artery.

A finite volume numerical approach for predicting heat transfer in presence of thermal contact resistance

A finite volume numerical approach for predicting heat transfer in presence of thermal contact resistance

A mathematical model for radiative peristaltic flow of Jeffrey fluid in curved channel with Joule heating and different walls: Shooting technique analysis

The peristaltic phenomenon has intended the researcher’s attention due to its extensive applications in bio-mechanics, industries and biological sciences. The applications of peristaltic transport problems are observed in the transportation of cilia, food mixing in digestive tract, small blood vessels vasomtion, urine transportation etc. Following to such motivating applications in minds, this theoretical analysis presents the peristaltic flow of magnetized Jeffery fluid through accounted by curved channel in presence of heat transfer. The assumed flow is confined by different wave frames. The heat transfer inspection has been performed by utilizing the non-linear thermal radiation and joule heating features. The curvilinear coordinate system is used to model the two dimensional, laminar and incompressible Jeffrey fluid with peristaltic phenomenon. The partial differential equations are transformed into ordinary differential equations in view of appropriate quantities. The implementation of wave length with long magnitude and the assumptions of smaller Reynolds assumptions, the governing system of ordinary system is solved numerically by using shooting technique. The dynamic of involved quantities and physical variables is observed carefully. A declining observation in the temperature in all forms of waves has been noticed for increasing the viscoelastic parameter. The heat transfer coefficient for all waves enhanced for the radius of curvature. Moreover, the velocity of the fluid declines in the lower half of the channel and rises near upper wall of the curved channel due to magnetic parameter.

Interfacial thermal resistance between nanoconfined water and silicon: Impact of temperature and silicon phase

Molecular dynamics simulations are used to investigate the interfacial thermal resistance (Kapitza resistance) between crystalline or amorphous silicon and nanoconfined water at nanoscale. The simulations are performed under various conditions such as: different silicon phases (crystalline or amorphous), various water slab thicknesses, average system temperature and temperature difference between the thermostats. The results indicate that the Kapitza resistance is larger between crystalline silicon slabs and water (≈1.2 10−8 K m2 W−1) than between amorphous silicon slabs and water (≈0.7 10−8 K m2 W−1), which can be interpreted as a density effect using the acoustic mismatch model. We have not observed significant size effects related to the water slab thickness on the Kapitza resistance nor on the thermal conductivity of the nanoconfined water. Furthermore, the interfacial thermal resistance is linearly impacted by temperature unless the temperature difference between the thermostats is larger than 50 K. The presented results provide new insights in nano heat transfer in presence of a solid/liquid interface.

Modelling Radiative and Convective Thermal Exchanges over a European City Center and Their Effects on Atmospheric Dispersion

Micro-meteorological studies of urban flow and pollution dispersion often assume a neutral atmosphere and often the three-dimensional variation in temperature fields and flow around buildings is neglected in most building energy balance models. The aim of this work is to present the results of development and validation of a three-dimensional tool coupling thermal energy balance of the buildings and modelling of the atmospheric flow and dispersion in urban areas. To do so, a 3D microscale atmospheric radiative scheme has been developed in the atmospheric module of the computational fluid dynamics (CFD) code Code_Saturne adapted to detailed building geometries. The full coupling of the radiative transfer and fluid dynamics models has been validated with idealized cases. In this paper, our focus is to simulate and compare with measurements the diurnal evolution of the brightness surface temperatures and the momentum and energy fluxes for a neighborhood in the city center of Toulouse, in the southwest part of France. This is performed by taking into account the 3D effects of the flow around the buildings and all thermal exchanges, in real meteorological conditions, and compare them to aircraft infrared images and in situ measurements on a meteorological mast. The calculation mesh developed for the city center and the simulation conditions for the selected day of the field campaign are presented. The results are evaluated with the measurements from the Canopy and Aerosol Particles Interactions in TOulouse Urban Layer experiment (CAPITOUL). In addition, the second purpose of this work is to investigate a hypothetical release of passive pollutant dispersion in the same area of Toulouse under different thermal transfer conditions for the street and the buildings surfaces: neutral and 3D radiative transfer heating. The presence of heat transfer continually modifies the airflow field while the airflow in the neutral case reaches a stationary state. Compared to the neutral case, taking into account the thermal transfer enhances the turbulence kinetic energy and vertical velocity (especially at the roof level) due to buoyancy forces. The simulation results also show that the thermal effects considerably alter the plume shape.

Experimental studies on condensation of steam mixed with noncondensable gas inside the vertical tube in a pool filled with subcooled water

Abstract A passive containment cooling system with immersed condensers has been proposed as one of the alternatives for the Advanced Heavy Water Reactor (AHWR) being designed in India. The system removes residual/decay heat released into the containment through the immersed condensers kept in a pool of water following loss of coolant accident. An important aspect of the immersed condensers is the potential degradation of its performance due to the presence of noncondensable gases. Experiments are performed to obtain reliable data on condensation phenomena in presence of air. These experiments are conducted on full-scale tubes of condensers immersed in a pool of water maintaining similar conditions as in the prototype of AHWR. A method has been proposed for the determination of the local heat transfer rate using correlations given in literature. The parametric effects of air mass fraction, pressure, steam flow, etc. on condensation heat transfer in presence of noncondensable gas have been studied. The experimental results are compared with the correlations given in literature.

Numerical Study of Unsteady Boundary Layer Flow of a Biomagnetic Fluid over a Horizontal Stretching Sheet with Magnetic Dipole

This paper focuses on the theoretical and numerical investigation of the unsteady, viscous, incompressible, two-dimensional laminar boundary layer flow of a Newtonian biomagnetic fluid over a stretching sheet under the influence of an applied magnetic field in the presence of heat transfer. The magnetic field is induced by a magnetic dipole placed below the stretching sheet. The magnetic field intensity represents the magneto-thermo-mechanical coupling. This allows exclusion of the biofluid that is distant from the sheet at Curie temperature to avoid further magnetization. The unsteadiness of the flow is discernible in the fluid flow properties. The mathematical model of the problem conforms to the principles of Magnetohydrodynamics (MHD) and Ferrohydrodynamics (FHD). In this work, the study is performed on a specific biofluid, human blood. The modified Stokes principle is used to implement the model under the assumption that along with the three thermodynamic variables P, ρ, and T, the Biomagnetic Fluid Dynamics (BFD) fluid behavior can be characterized as a function of magnetization M. To describe the physical problem, a coupled non-linear system of ordinary differential equations subject to appropriate boundary conditions is derived from Navier-Stokes and thermal energy equations by performing non-dimensionalization of the considered variables. To solve these equations, the dsolve routine in the MAPLE software is used. Numerical results for flow profiles and the local skin friction coefficient (Cfx) and the local Nusselt number (Nux) are discussed for different values of unsteadiness parameter (A), biomagnetic interaction parameter (B) and a rational quantity (ϵ). The achieved results are compared with previously published work for steady state flow, and they seem to be in good agreement. It is found that MHD and FHD interaction parameters affect significantly on the velocity, temperature and pressure field. A successful completion will bring interesting results for better understanding of the biomagnetic fluid flow characteristics and can be beneficial to medical and bioengineering applications; particularly for estimating the characteristics of blood flow in stenosed arteries.

A Finite Volume Numerical Approach for Predicting Heat Transfer in Presence of Thermal Contact Resistance

A Finite Volume Numerical Approach for Predicting Heat Transfer in Presence of Thermal Contact Resistance

Divergent channel flow of Casson fluid and heat transfer with suction/blowing and viscous dissipation: Existence of boundary layer

The boundary layer existence in divergent porous channel of non-Newtonian Casson fluid with heat transfer in presence of suction/blowing and viscous dissipation is studied. Nonlinear coupled ODEs are obtained from governing PDEs and the conditions under which boundary layer structure for Casson fluid exists by controlling backflow are explored. Numerical solutions are also obtained using “bvp4c”, a MATLAB package. The study reveals that if mass suction exceeds a certain amount which is dependent on Casson parameter then only boundary layer flow is possible and as Casson parameter increases, the requirement of mass suction for boundary layer flow reduces. In addition, rheological characters of Casson fluid and viscous dissipation have a major impact on temperature distribution and due to these, the temperature falls lower than free stream temperature within the boundary layer region.

Numerical Solution for Unsteady Acceleration MHD Third-Grade Fluid Flow in a Rotating Frame Through Porous Medium Over Semi-Infinite Boundary Condition with a Presence of Heat Transfer

The aim of this work is to present a suitable numerical solution for unsteady non-Newtonian third-grade fluid which rotates at z -axis and pass through a porous medium. The fluid flows in magnetic field with constant acceleration and the semi-infinite boundary condition are highlighted. The fluid problem is also deal with heat transfer. The nonlinear partial differential equation is discretised using the finite difference method (FDM). The linear system obtained for three different domains (lengths). Consequently, the asymptotic interpolation method is merged to solve problems of large sizes. This hybrid method yielded results that satisfied the boundary condition that reaches zero as length grows to infinite length. For velocity profile and temperature distribution, a comparison of FDM and hybrid method is shown. It is discovered that the hybrid method produces better results than FDM for this infinitely large problem. Several analyses have been carried out to investigate the effect of various fluid parameter values. The findings reveal that as the porosity parameter increases, the velocity decreases. The Grashof and Prandtl numbers demonstrate the relationship to the temperature distributions. The effects of the magnetic field and the non-Newtonian parameters were also illustrated, as these parameters influence the velocity distribution of the fluid flow.

ANALYTICAL STUDY FOR THE BOUNDARY LAYER FLOW IN THE PRESENCE OF HEAT TRANSFER THROUGH A POROUS MEDIUM

In this paper we study a problem of the boundary layer flow through a porous media in the presence of heat transfer. Here we consider high porosity bounded by a semi-infinite horizontal plate. The main aim of this study is to point out local similarity transformations for the boundary layer flow, through a homogeneous porous medium. Here we applying finite difference schemes to find out the numerical solutions of the problem. The free stream velocity and the temperature far away from the plate are exponential function of variables.

Effect of Heat Transfer on Newtonian Flow Between Concentric Elliptical Regions

In the present study, the slow and steady flow of Newtonian fluid in the presence of heat transfer in annular region formed by two concentric ellipses is considered. The concentric ellipses in z-plane are mapped to concentric circles in ζ-plane using conformal transformation. Analytical solutions for velocity and temperature are obtained in ζ-plane and the same are graphically depicted. The effects of dimensionless parameter such as Grashof number Gr, heat flux β, initial temperature at wall of inner ellipse θ0 and area of cross section of concentric ellipses on velocity, rate of flow and temperature have been studied. The graphical representation shows that the velocity, temperature is enhanced with increase in Gr and area of cross section between ellipses, and decreases with increase in heat flux β.

Flow and heat transfer in eccentric annulus

Eccentric annular regions formed by two impermeable cylinders are considered. Flow of Newtonian fluid in the annular region in the presence of heat transfer is studied. The eccentric annulus is mapped to concentric annular region through conformal mapping. Analytical solution for both temperature and velocity is obtained and graphically depicted. An increase in eccentricity results in an increase in velocity but a decrease in temperature.

CPSM Simulation of the Variable Properties’ Role in MHD Non-Newtonian Micropolar Nanofluid Flow Over a Stretching Porous Sheet (Flow Filtration)

In this manuscript, to modify the fluid thermophysical properties, the alumina suspended nanoparticles were immersed in two different kinds of base fluids, ethylene glycol with Prandtl number (Pr = 204) and water with (Pr = 6.785). The combination between Powell–Eyring model and micropolar fluid was utilized to describe a 2D steady nanofluid flow along a stretching permeable sheet. An inconvenience through a porous material was illustrated by Darcy–Forchheimer (D–F) expression. As it is known, the nanofluid thermophysical properties are not constants especially in the presence of heat transfer; hence, the viscosity and thermal conductivity were employed as variable functions of the temperature and nanoparticle concentration. As well as in the present work, the microrotation and spin gradient viscosities, which were always constant in all the above studies, have been employed as variable functions of the temperature. The governing mathematical equations have been calculated numerically via the Chebyshev pseudospectral method/Mathematica code. A perfect agreement was obtained between some numerical outcomes and previous published data. Also, the present numerical outcomes for the distributions of temperature, concentration, velocities, skin friction, wall couple stress, Nusselt and Sherwood numbers are represented in tabular form and by drawing against different controlling parameters in the ranges $$ \phi (0 - 20\% ),A(0.01 - 1),\,n(0 - 5),\,\beta_{1} ,\,\beta_{1} ,\,\beta_{3} \,(0 - 0.7),\,$$ $$ {\text{Fr}},\,{\text{Da,}}\,K_{c} ,\,{\text{Sc}}\,(0.1 - 2),\,\Delta \,(0.1 - 10),S\,( - 1\, - \,1)$$ , and $$ M(0 - 20)$$ . In this article, it is confirmed that utilizing the nanofluid viscosity/thermal conductivity as a variable function of both the nanoparticle concentration and the temperature had a great importance and is a vital factor to reinforce the rate of heat transfer. Finally, a new result was gotten in this work; when the variable microrotation viscosity parameter rose, the angular velocity profile raised.

Nonlinear propagation and parameters excitation of ultrasound

The formula for the nonlinear propagation of harmonics is obtained by using the generalized Navier-Stokes equations and the modified equations of state, considering the presence of heat transfer and fluid viscidity. The quantitative relationship among the harmonic pressure, initial sound pressure amplitude, frequency and the media property is obtained by approximately solving the single-frequency acoustic equation. In this paper, the hamonics’ distributions and propagations in the radiation field of single- and double-frequency sound source with different driving pressures and frequencies are discussed. It is found that new harmonics constantly appear in the sound field, and each-order harmonic of excitation gradually increases and then weakens with the increase of distance. The amplitude of harmonic pressure increases with the increase of the driving acoustic pressure near the sound source, but decreases with the increase of the frequency. Compared with the single-frequency field, the dual-frequency field has a large propagation distance, a very uniform acoustic energy distribution, and a large harmonic content in the far-field when the input total sound energy is constant. The physical mechanism is that the higher driving frequency causes a faster acoustic loss, a slower harmonic accumulation, and a smaller sound propagation distance. The higher driving pressure causes the much fundamental sound energy to be transferred, the more harmonics to be generated, the fundamental wave to be attenuated faster, and the negative effect of sound pressure on far-field sound energy to be increased. Through the analysis, it is found that the multi-frequency sound source can increase the propagation distance of sound, and improve the uniformity of sound energy distribution.

Two-phase MHD Flow through Porous Medium with Heat Transfer in a Horizontal Channel

The present study deals with two layered MHD immiscible fluid flow through porous medium in presence of heat transfer through parallel plate channel. The fluids are incompressible, and flow is fully developed. The fluids are of different viscosities and thermal conductivities so flowing without mixing each other. Two different phases are accounted for study and are electrically conducting. Temperature of the walls of parallel plate channel is constant. Rheological properties of the immiscible fluids are constant in nature. The flow is governed by coupled partial differential equations which are converted to ordinary differential equations and exact solutions are obtained. The velocity profile and temperature distribution are evaluated and solved numerically for different heights and viscosity ratios for the two immiscible fluids. The effect of magnetic field parameter M and porosity parameter K is discussed for velocity profile and temperature distribution. Combined effects of porous medium and magnetic fields are accelerating the flow which, can be helpful in draining oil from oil wells.