Effects of Heat Generation/Absorption on Magnetohydrodynamics Flow Over a Vertical Plate with Convective Boundary Condition

Heat generation effect in a steady two-dimensional magnetohydrodynamics (MHD) flow over a moving vertical plate with a medium porosity has been studied. By similarity transformation variables, the coupled non-linear ordinary differential equations describing the model are obtained. The resulting equation is then solved, using Galerkin Weighted Residual Method (GWRM), where the effect of heat generation, Magnetic Parameter as well as other physical parameters encountered were examined and discussed. Some of the major findings were that increase in heat generation and convective heat parameter enhances the plate surface temperature as well as temperature field which allows the thermal effect to penetrate deeper into the quiescent fluid.

The vibration of thermoelastic silicon nitride Nanobeam based on green-naghdi theorem type-II subjected to mechanical damage and ramp-type heat

In this work, an analysis for thermoelastic homogeneous isotropic nanobeams under damage mechanics consideration was built. Under easily supported boundary conditions with fixed side ratios, the Green-Naghdi model type-II, an extended thermoelasticity theory model, has been utilized. For the governing differential equations, the Laplace transforms technique was used on the time variable. The answers were found in the domain of the Laplace transform. Tzou’s approximation approach based on an iteration formula was used to calculate the Laplace transform inversions numerically. The numerical findings for a rectangular silicon nitride thermoelastic nanobeam have been obtained and validated. As a case study, we assumed that the beam is thermally loaded with ramp-type heat and that its two edges are simply supported. Figures representing different scenarios have been used to display the numerical results. Mechanical damage value, ramp-time heat parameter and beam thickness are all reported to have a substantial influence on all of the examined functions.

Cross Diffusion Effect on Linear and Nonlinear Double Diffusive Convection in a Viscoelastic Fluid Saturated Porous Layer with Internal Heat Source

Double diffusive convection in a binary viscoelastic fluid saturated porous layer in the presence of a cross diffusion effect and an internal heat source is studied analytically using linear and nonlinear stability analysis. The linear stability theory is based on the normal mode technique, while the nonlinear theory is based on a minimal representation of truncated double Fourier series. The modified Darcy law for the viscoelastic fluid of the Oldroyd type is considered to model the momentum equation. The onset criterion for stationary and oscillatory convection and steady heat and mass transfer have been obtained analytically using linear and nonlinear theory, respectively. The combined effect of an internal heat source and cross diffusion is investigated. The effects of Dufour, Soret, internal heat, relaxation and retardation time, Lewis number and concentration Rayleigh number on stationary, oscillatory, and heat and mass transport are depicted graphically. Heat and mass transfer are presented graphically in terms of Nusselt and Sherwood numbers, respectively. It is reported that the stationary and oscillatory convection are significantly influenced with variation of Soret and Defour parameters. An increment of the internal heat parameter has a destabilizing effect as well as enhancing the heat transfer process. On the other hand, an increment of internal heat parameter has a variable effect on mass transfer. It is found that there is a critical value for the thermal Rayleigh number, below which increasing internal heat decreases the Sherwood number, while above it increasing the internal heat increases the Sherwood number.

Effect of Chemical Reaction and Thermo-Diffusion in an Electrically Conducting Walters’ B Fluid over a Vertical Stretching Surface

In this article, the significance of chemical reaction and thermo-diffusion in Walters’ B fluid is examined with medium porosity under the influence of non-uniform heat generation\absorption. The nonlinear ordinary differential equations describing the flow are obtained via similarity variables and tackled by Homotopy Analysis Method. The results show among others that involvement of chemical reaction contributes to the shrinking of concentration buoyancy effect while dimensionless temperature overshoot with large values of convective heat parameter and heat generation\absorption which enable thermal potency to gain entrance to the quiescent-fluid, indicating that the two parameters can be used for drying of the components.

Experimental investigation of linear low density polyethylene composites based on coir for rotational molding process

Rotational Molding is a plastic manufacturing process mainly implemented to produce stress free hollow products. Linear Low Density Polyethylene (LLDPE) is widely preferred as base resin for molding roto molded product, but it displays moderate value in some critical applications where strength is the major criteria. Additives can fill the gap in sustaining the necessary strength needed. In the present work, an attempt has been made to analyze the optimum percentage of coir reinforced with LLDPE for rotational molding technique to provide requisite processability for rotational molding process. Coir in its powder form is mixed at concentrations varying in the range of 3% to 20% with respect to LLDPE. In order to justify the prerequisite of processability for rotational molding, various experiments namely FTIR, MFI, rheology and thermal analysis were conducted. FTIR suggested the range of 5% to 15% wherein the significance of LLDPE and coir peaks can be observed. MFI test supported FTIR result which ended in considering 3% to 12% by weight ratio suitable in terms of flow ability. Rheological and thermal analysis subjecting to shear and heat parameter respectively, confirmed the range of 10 weight percentage of coir or below is suitable in terms of material processability. From the experimental results, it is concluded that 10% or less concentration of coir fiber in LLDPE as an optimum range of blend yielding better processability for rotational molding process.

Magnetohydrodynamic (MHD) stagnation point flow of Casson fluid over a stretched surface with homogeneous–heterogeneous reactions

This article communicates the study of magnetohydrodynamic (MHD) stagnation point flow of Casson liquid towards a stretched surface. Chemical reaction model involving both heat and mass transfer is established. Effects of viscous dissipation and Joule heating are also considered. Appropriate transformations yield strong nonlinear ordinary differential system. The obtained nonlinear systems have been solved through built-in shooting method. Velocity field shows decreasing behavior for higher estimation of magnetic parameter while temperature field shows increasing behavior for larger homogeneous heat parameter. Graphical behaviors of velocity, temperature and concentration are analyzed comprehensively corresponding to various pertinent parameters.

Effects of Heat Transfer and an Endoscope on Peristaltic Flow of a Fractional Maxwell Fluid in a Vertical Tube

We investigate the unsteady peristaltic transport of a viscoelastic fluid with fractional Maxwell model through two coaxial vertical tubes. This analysis has been carried under low Reynolds number and long wavelength approximations. Analytical solution of the problem is obtained by using a fractional calculus approach. The effects of Grashof number, heat parameter, relaxation time, fractional time derivative parameter, amplitude ratio, and the radius ratio on the pressure gradient, pressure rise, and the friction forces on the inner and outer tubes are graphically presented and discussed.

CFD Optimization of Design for IGBT Air-Cooled Heat Sink

Power dissipation problems for Insulated Gate Bipolar Transistor (IGBT) are requiring increasingly complex design solutions. While designs that are more efficient make thermal management possible, current systems still require CFD methods for dissipating heat. Parameter optimization of the air-cooled heat sink is carried out to cool a three-chip, 2400w IGBT plate. The parameters are compared using maximum junction temperature and fan efficiency.