Presence Of Thermal Radiation Effects Research Articles

Pulsatile Darcy flow of water‐based thermally radiative carbon nanotubes between two concentric cylinders

AbstractIt is perceived that the addition of nanoparticles has increased the heat transfer capabilities of ordinary fluids significantly for both turbulent and laminar flow regimes. The current investigation analyzes the effects of carbon nanotubes (CNTs) on the pulsatile flow and heat transfer characteristics of viscous fluid between two concentric cylinders in the presence of thermal radiation effects. The flow of Magneto‐hydrodynamic (MHD) viscous fluid in a Darcy type porous medium is driven by the pressure gradient, assumed as a periodic function of time. The fluid is taken as optically thick and radiations can travel only a short distance within the fluid. The magnetic field is applied perpendicular to the direction of flow and the induced magnetic field is considered negligible. The conventional governing equations are based upon partial differential equations affected by the viscosity of the base fluid, effective thermal conductivity, and thermophysical characteristics of CNTs nanoparticles. The exact solutions are obtained in the form of the modified Bessel functions of the first and second kind. The effect of the flow control parameters like thermal radiation parameter , nanoparticles volume fraction , and Darcy number are illustrated through graphs. Based on a comprehensive analysis, it is concluded that the addition of single‐walled carbon nanotubes provides higher velocity and temperature distribution of nanofluid when compared with the multi‐walled carbon nanotubes.

Dual solutions for MHD flow of a water-based TiO2-Cu hybrid nanofluid over a continuously moving thin needle in presence of thermal radiation

In this analysis, the flow and heat transfer characteristics of an aqueous hybrid nanofluid with TiO2 and Cu as the nanoparticles past a horizontal slim needle in the presence of thermal radiation effect is investigated. We hope that the present research is applicable in fiber technology, polymer ejection, blood flow, etc. The Prandtl number of the base fluid is kept constant at 6.2. The needle is considered thin when its thickness does not exceed that of the boundary layer over it. Using the similarity transformation method, the governing PDEs are transformed to a set of non-linear ODEs. Then, the converted ODEs are numerically solved with help of bvp4c routine from MATLAB. Results indicate that the dual similarity solutions are obtained only when the slim needle moves in the opposite direction of the free stream. In addition, the first solutions are stable and physically realizable. Besides, the second nanoparticle's mass and also the magnetic parameter lead to decrease the range of the velocity ratio parameter for which the solution exists.

MHD graphene-polydimethylsiloxane Maxwell nanofluid flow in a squeezing channel with thermal radiation effects

The magnetohydrodynamic (MHD) graphene-polydimethylsiloxane (PDMS) nanofluid flow between two squeezing parallel plates in the presence of thermal radiation effects is investigated. The energy efficiency of the system via the Bejan number is studied extensively. The governing partial differential equations are converted by using the similarity transformations into a set of coupled ordinary differential equations. The set of these converted equations is solved by using the differential transform method (DTM). The entropy generation in terms of the Bejan number, the coefficient of skin-friction, and the heat transfer rate is furthermore investigated under the effects of various physical parameters of interest. The present study shows that the Bejan number, the velocity and thermal profiles, and the rate of heat transfer decrease with a rise in the Deborah number De while the skin-friction coefficient increases. It is also observed that the entropy generation due to frictional forces is higher than that due to thermal effects. Thus, the study bears the potential application in powder technology as well as in biomedical engineering.

Concentration-dependent viscosity and thermal radiation effects on MHD peristaltic motion of Synovial Nanofluid: Applications to rheumatoid arthritis treatment

Background and ObjectiveThe biomedical fluid which fills the Synovial joint cavity is called Synovial fluid which behaves as in the fluid classifications to Non-Newtonian fluids. Also it's described as a several micrometers thick layer among the interstitial cartilages with very low friction coefficient. Consequently, the present paper opts to investigate the influence of the concentration-dependent viscosity on Magnetohydrodynamic peristaltic flow of Synovial Nanofluid in an asymmetric channel in presence of thermal radiation effect. MethodOur problem is solved for two models, in the first model which referred as Model-(I), viscosity is considered exponentially dependent on the concentration. Model-(2), Shear thinning index is considered as a function of concentration. Those models are introduced for the first time in peristaltic or Nanofluid flows literature. The governing problem is reformulated under the assumption of low Reynolds number and long wavelength. The resulting system of equations is solved numerically with the aid of Parametric ND Solve. ResultsDetailed comparisons have been made between Model-(I) and Model-(2) and found unrealistic results between them. Results for velocity, temperature and nanoparticle concentration distributions as well as pressure gradient and pressure rise are offered graphically for different values of various physical parameters. ConclusionsSuch models are applicable to rheumatoid arthritis (RA) treatment. Rheumatoid arthritis patients can be treated by applying the magnetic field on an electrically conducting fluid, due to the movement of the ions within the cell which accelerates the metabolism of fluids.

Analysis of Heat Transfer of Cu-Water Nanofluid Flow Past a Moving Wedge

In this paper, heat transfer of a steady, two-dimensional, incompressible Cu-water nanofluid flow over a moving wedge in the presence of thermal radiation effect are investigated. Gyarmati's variational principle developed on the thermodynamic theory of irreversible processes is employed to solve the problem numerically. The governing boundary layer equations are approximated as simple polynomial functions, and the functional of the variational principle is constructed. The Euler-Langrange equations are reduced to simple polynomial equations in terms of boundary layer thicknesses. The velocity and temperature profiles as well as skin friction and heat transfer are analyzed for various parameters. The obtained numerical solutions are compared with the previously published results and are found to be in good agreement.

Thermal radiation effect on MHD Flow and heat transfer analysis of Williamson nanofluid past over a stretching sheet with constant wall temperature

In this paper, the boundary layer flow of Williamson nanofluids past over a stretching sheet in the presence of thermal radiation effect is analyzed. Using similarity transformations, the governing equations are reduced to a set of nonlinear ordinary differential equations (ODEs). These equations are solved numerically by with shooting method. The effects of Williamson parameter, magnetic parameter, radiation parameter, Prandtl number on velocity, temperature and concentration fields are shown graphically and discussed. It is found that the rate of heat transfer is higher for Williamson nanofluid compared to the classical viscous fluid. Also, the comparisons with existing results are provided in the literature.

Investigation of MHD Go-water nanofluid flow and heat transfer in a porous channel in the presence of thermal radiation effect

In this paper, flow and heat transfer of MHD Go-water nanofluid between two parallel flat plates in the presence of thermal radiation are studied. One of plates is externally heated and cooled by coolant injection through the other plate, which also expands or contracts with time. A similarity transformation is used to transmute the governing momentum and energy equations into non-linear ordinary differential equations with the appropriate boundary conditions. The obtained non-linear ordinary differential equations are solved by Duan–Rach Approach (DRA). This method allows us to find a solution without using numerical methods to evaluate the undetermined coefficients. This method modifies the standard Adomian Decomposition Method by evaluating the inverse operators at the boundary conditions directly. The impacts of various parameters such as the Reynolds number, the expansion ratio, the magnetic parameter, the power law index, the solid volume fraction and the radiation parameter are investigated on the velocity and temperature. Furthermore, the value of the Nusselt number is calculated and presented through figures. The results indicate that the temperature profile and the Nusselt number have a direct relationship with the solid volume fraction and have an inverse relationship with the radiation parameter. In addition, the limiting cases are gained and found to be in an excellent agreement with the previous works.

Convective heat transfer in a nanofluid-saturated porous cavity with the effects of various aspect ratios and thermal radiation

ABSTRACTThis article reports a fundamental numerical study made to understand the effects of aspect ratio and thermal radiation in a porous cavity filled with nanofluid. The vertical walls of the cavity are insulated while the bottom and top horizontal walls are maintained at constant but different temperatures. The governing equations are solved by using a finite volume method (FVM) on a uniformly staggered grid system. The effects of the pertinent parameters, namely, Richardson number, aspect ratio, radiation parameter, Darcy number, and solid volume fraction are investigated in detail. The computational results are presented in the form of isotherm, streamline, midplane velocity, and Nusselt numbers. The effects of solid volume fraction and thermal radiation are not significant for and 0.5. In general, the results indicate that the convective mechanism is suppressed by radiation, which causes a reduction in the overall heat transfer rate. It is also found that the overall heat transfer rate increases with an increase of Darcy number and solid volume fraction in the presence of thermal radiation effect.

Unsteady MHD double diffusive convection in the stagnation region of an impulsively rotating sphere in the presence of thermal radiation effect

This paper discusses the magnetohydrodynamic rotating flow, heat and mass transfer of a laminar incompressible viscous electrically conducting fluid in the stagnation region of an impulsively rotating sphere in the presence of thermal radiation effect. Non-similar solution is presented and fourth order Runge–Kutta–Fehlberg method is used to solve the resulting non-similar equations. The results of the problem are presented in terms of velocity profiles in the x-direction, temperature distributions and concentration distributions as well as surface shear stresses in both x-and y-directions, heat transfer rate and mass transfer rate. It is found that the temperature distributions increases as the radiation parameter increases while the increase in the buoyancy ratio reduce the temperature distributions. Also, the rotation parameter has a positive effect on the flow, heat and mass transfer rates. Further, the increase in the buoyancy parameter causes an increase in the velocity profiles in velocity profiles in x-direction as well as the surface shear stress in the x-direction and rate of heat transfer.

Local Non-similarity Solution for MHD Mixed Convection Flow of a Nanofluid Past a Permeable Vertical Plate in the Presence of Thermal Radiation Effects

Combined heat and mass transfer on mixed convection non-similar flow of electrically conducting nanofluid along a permeable vertical plate in the presence of thermal radiation is investigated. The governing partial differential equations of the problem are transformed into a system of non linear ordinary differential equations by applying the Sparrow–Quack–Boerner local non-similarity method (LNM). Furthermore, the obtained equations are solved numerically by employing the Fourth or fifth order Runge Kutta Fehlberg method with conjunction to shooting technique. The profiles of flow and heat transfer are verified by using five types of nanofluids of which metallic or nonmetallic nanoparticles, namely Copper (Cu), Alumina (Al2O3), Copper oxide (CuO), silver (Ag) and Titanium (TiO2) with a water-based fluid. Rosseland approximation model on black body is used to represent the radiative heat transfer. Effects of thermal radiation, buoyancy force parameters and volume fraction of nanofluid on the velocity and temperature profiles in the presence of suction/injection are depicted graphically. Comparisons with previously published works are performed, and excellent agreement between the results is obtained. The conclusion is that the flow fields is affected by these parameters.

Numerical/Laplace transform analysis for MHD radiating heat/mass transport in a Darcian porous regime bounded by an oscillating vertical surface

Analytical and numerical solutions of a non-linear MHD flow with heat and mass transfer characteristics of an incompressible, viscous, electrically conducting and Boussinesq’s fluid over a vertical oscillating plate embedded in a Darcian porous medium in the presence of thermal radiation effect have been presented. The fluid considered here is gray, absorbing/emitting radiating, but non-scattering medium. At time t>0, the plate temperature and concentration near the plate raised linearly with time t. The dimensionless governing coupled, non-linear boundary layer partial differential equations are solved by an efficient, accurate, extensively validated and unconditionally stable finite difference scheme of the Crank–Nicolson type as well as by the Laplace Transform technique. An increase in porosity parameter (K) is found to depress fluid velocities and shear stress in the regime. Also it has been found that, when the conduction-radiation (R) increased, the fluid velocity and the temperature profiles decreased. Applications of the study arise in materials processing and solar energy collector systems.

Thermal radiation effects on MHD forced convection flow adjacent to a non-isothermal wedge in the presence of a heat source or sink

This work is focused on the steady-state, hydromagnetic forced convective boundary-layer flow of an incompressible Newtonian, electrically-conducting and heat-generating/absorbing fluid over a non-isothermal wedge in the presence of thermal radiation effects. The wedge surface is assumed permeable so as to allow for possible wall suction or injection. Also included in the model are the effects of viscous dissipation, Joule heating and stress work. The governing partial differential equations for this investigation are derived and transformed using a non-similarity transformation. In deriving the governing equations, a temperature-dependent heat source or sink term is employed and the Rossland approximation for the thermal radiation term is assumed to be valid. The obtained non-similar equations are solved numerically by an implicit, iterative, tri-diagonal finite-difference method. Comparisons with previously published work on various special cases of the problem are performed and the results are found to be in excellent agreement. Numerical results for the velocity and temperature profiles for a prescribed magnetic parameter as well as the development of the local skin-friction coefficient and local Nusselt number with the magnetic parameter are presented graphically and discussed. This is done in order to elucidate the influence of the various parameters involved in the problem on the solution.