Significance of Stefan Blowing and Convective Heat Transfer in Nanofluid Flow Over a Curved Stretching Sheet with Chemical Reaction

The applications of fluid flow with Newtonian heating effect include conjugate heat conveyance around fins, petroleum industry, and heat exchangers designing. Motivated from these applications, an attempt has been made to analyze the stream of viscous nanomaterial subjected to a curved stretching sheet. Also, heat and mass transport mechanism due to a chemical reaction, Brownian and thermophoresis motion are discussed. The equations of the mathematical model are formulated by considering the Newtonian heating and Stefan blowing conditions at the boundary. These modelled equations are then changed to a system of nonlinear equation involving ordinary derivatives of a function by means of suitable similarity transformations. Further, shooting technique with Runge-Kutta-Fehlberg-45 process is utilized to solve the reduced equations. Outcomes disclose that, the gain in Stefan blowing parameter escalates the liquid velocity. The intensification in chemical reaction rate parameter deteriorates the concentration gradient. The rise in Schmidt number and thermophoresis parameter drops the mass transfer rate. The increased values of Newtonian heating parameter with respect to thermophoresis parameter decays the heat transport rate.

Buoyancy Effect on MHD Slip Flow and Heat Transfer of a Nanofluid Flow Over a Vertical Porous Plate

This study investigated the boundary layer flow and heat transfer aspects of a nanofluid over a porous plate with thermal radiation.Using suitable similarity transformations,partial differential equations were converted into ordinary differential equations and then solved numerically with the help of the Runge-Kutta scheme. The effects of various parameters were analyzed such as Prandtl number 𝑃𝑟, Lewis number 𝐿𝑒, Thermophoresis 𝑁𝑡, Mixed convection parameter λ,Brownianmotion 𝑁𝑏, Magnetic parameter M, and Suction/Blowing parameter S. The results were depicted with the help of graphs.

Series solutions for the flow in the vicinity of the equator of an MHD boundary-layer over a porous rotating sphere with heat transfer

In this paper, an analytical method (DTM-Pad?) is employed to solve the flow and heat transfer near the equator of an MHD boundary-layer over a porous rotating sphere. This method is used to give solutions of nonlinear ordinary differential equations with boundary conditions at infinity. The velocity components in all directions (meridional, rotational and radial) and temperature fields are derived. The obtained results are verified with the results of numerical solution. A very good agreement can be observed between them. The effect of involved parameters such as magnetic strength parameter, rotation number, suction/blowing parameter and Prandtl number on the all-different types of velocity components, temperature field and surface shear stresses in meridional and rotational directions, infinite radial velocity and rate of heat transfer is checked and discussed.

Numerical Study of Laminar Flow and Mass Transfer for In-Line Spacer-Filled Passages

Performance calculations for laminar fluid flow and mass transfer are presented for a passage containing cylindrical spacers configured in an inline-square arrangement, typical of those employed in the process industries. Numerical calculations are performed for fully-developed flow, based on stream-wise periodic conditions for a unit cell and compared with those obtained for developing regime in a row of ten such units. The method is validated for an empty passage, i.e., a plane duct. Results are presented for the normalized mass transfer coefficient and driving force, as a function of mean flow Reynolds number, and also the wall mass flux, or blowing parameter. Both constant and variable wall velocities were considered, the latter being typical of those found in many practical membrane modules.

Numerical Study of Laminar Flow and Mass Transfer for In-Line Spacer-Filled Passages

Performance calculations for laminar fluid flow and mass transfer are presented for a spacer-filled passage containing cylindrical spacers configured in an inline-square arrangement, typical of those employed in the process industries. Numerical calculations are performed for fully-developed flow, based on stream-wise periodic conditions for a ‘unit cell’ and compared with those obtained for developing regime in a row of 10 such units. The method is validated for an empty passage (i.e. a plane duct). Results are presented for the normalized mass transfer coefficient and driving force, as function of mean flow Reynolds number, and also the wall mass flux, or blowing parameter. Both constant and variable wall velocities were considered, the latter being typical of those found in many practical membrane assemblies.

Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

Prediction of mass transfer effects is a key element in fuel cell design. In this paper, the results of a generalized analysis appropriate to a wide range of designs and flow conditions are presented. Mass transfer in a rectangular gas passage, diffusion layer, and the combination of the two is considered. Fully developed viscous flow is presumed to occur within the passage, while the incompressible form of Darcy’s law is prescribed for the diffusion layer. The mathematical foundations for a simple mass transfer analysis are presented. Detailed calculations are then performed by means of a computational fluid dynamics code. These results are then correlated according to the analytical methodology in terms of nondimensional numbers appropriate to mass transfer analysis; namely, the overall mass transfer driving force as a function of the blowing parameter. Parametric studies are performed for a range of geometries, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may readily be obtained from the two individual solutions for the conjugate mass transfer problem. This solution is quite general in its nature, and may readily be used to predict concentration polarization effects for a variety of fuel cells.

Transpired Turbulent Boundary Layers Subject to Forced Convection and External Pressure Gradients

The problem of forced convection transpired turbulent boundary layers with external pressure gradient has been studied by using different scalings proposed by various researchers. Three major results were obtained: First, for adverse pressure gradient boundary layers with suction, the mean deficit profiles collapse with the free stream velocity, U∞, but into different curves depending on the strength of the blowing parameter and the upstream conditions. Second, the dependencies on the blowing parameter, the Reynolds number, and the strength of pressure gradient are removed from the outer flow when the mean deficit profiles are normalized by the Zagarola/Smits [Zagarola, M. V., and Smits, A. J., 1998, “Mean-Flow Scaling of Turbulent Pipe Flow,” J. Fluid Mech., 373, 33–79] scaling, U∞δ*/δ. Third, the temperature profiles collapse into a single curve using the new inner and outer scalings proposed by Wang and Castillo [Wang, X., and Castillo, L., 2003, “Asymptotic Solutions in Forced Convection Turbulent Boundary Layers,” J. Turbulence, 4(006)], which produce the true asymptotic profiles even at finite Pe´clet number.

Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

An analysis is performed for mass transfer in a rectangular gas passage, porous diffusion layer, and the combination of the two. The results of detailed calculations are presented and correlated in terms of the mass transfer driving force as a function of the blowing parameter and geometry, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may be obtained for the conjugate mass transfer problem. This solution is quite general in its nature. The mathematical foundations are presented together with the details of the computational procedure used to obtain the results.

Non-Newtonian Flow Over a Wedge With Injection or Suction

A pseudo-similarity solution is obtained for the flow of an incompressible fluid of second grade past a wedge with suction or blowing at the surface. The non-linear differential equation is solved using quasi-linearization and orthonormalization. The numerical method developed for this purpose enables computation of the flow characteristics for any value of the parameters K, a, and b, where K is the dimensionless normal stress modulus of the fluid, a is related to the wedge angle, and b is the suction or blowing parameter. A significant effect of suction or blowing on the wall shear stress is observed. The present results match exactly with those from an earlier perturbation analysis for Kx2a ≤ 0.01 but differ significantly as Kx2a increases.