Search Results (6)

In the manufacturing sector, transport phenomena near the stagnation region are frequent, particularly in the polymer and extrusion processes, which require continuous improvement to raise the process’s quality standards. The aim of this study is to explore the improvement of heat and mass transmission using unsteady magnetohydrodynamic (MHD) hybrid nanofluid (HNF) flow over a stretching/shrinking cylinder with variable viscosity and Stefan blowing. The governed equations of heat and mass transfer processes are converted into ordinary differential equations (ODEs) using the appropriate transformations, and the resulting equations are then solved using the MATLAB package bvp4c. With an upsurge in the volume fraction of nanoparticles, the skin friction increases, but the reverse trend is detected with negative values for the unsteadiness constraint. The use of 2D graphs to show how important parameters affect the velocity, temperature, and concentration is thoroughly discussed. There is a discussion of the quantitative findings from the wall shear factor and the heat and mass transfer rates calculated for the stretching/shrinking cases. Full article

The discovery of hybrid carbon nanotubes shows the tendency toward the improvement of heat transfer performance in comparison to various classical fluids. This paper expands the novelty in utilizing the hybrid carbon nanotubes over vertical stretching/shrinking cylinder in presence of hydromagnetic and thermal radiation. It is essential to analyze the hydromagnetic due to its high potential capability especially in drug and gene release, hyperthermia effects as well as cell separation and manipulation in bio-medical field. The investigation on thermal radiation effect is added in this current study as it enhances the rate of heat transfer. To initiate this problem, partial differential equations (PDE) for the hybrid nanofluid flow with relevant boundary conditions (BCs) is set up and transformed into an ordinary differential equation (ODE). Adopting the similarity solutions and numerically solved using bvp4c (MATLAB). Findings on the variation of local Nusselt number, skin friction coefficient, shear stress and local heat flux having the effects of magnetic, $M,$curvature, ϒ, thermal radiation, Nr, mixed convection parameter, $\lambda$ as well as volume fraction of nanoparticles, $\phi$ are demonstrated and elaborated in detail. Moreover, the research reveals that duality of solutions occurs when the buoyance force is in opposing flow with respect to the fluid motion, $\lambda <0$, as well as shrinking area, $\epsilon <0$. The occurrence of magnetic reduces the heat transfer as well as skin friction coefficient. In addition, the skin friction coefficient and local Nusselt number tend to improve as volume fraction of nanoparticles and curvature are increased. In contrast, the low of thermal radiation enhance the heat transfer. Indeed, the consequences of using hybrid carbon nanotubes help intensify the skin friction coefficient and Nusselt number compared to SWCNT nanofluid and MWCNT nanofluid. These crucial findings may benefit the scientists and academicians hence giving an add-on value to their expertise. A stability analysis must be performed since there exists a non-unique solution throughout the computation. Full article

An investigation is conducted to study the flow and heat transfer on stagnation point over an exponentially stretching/shrinking cylinder filled with nanofluid in the presence of slip at the boundary. By using the appropriate exponential similarity transformation, the governing equations are converted into nonlinear ordinary differential equations and then solved computationally using bvp4c in Matlab software. The results of skin friction coefficient, heat transfer coefficient, velocity and temperature profiles on slip parameter, curvature parameter, nanoparticles as well as nanoparticle volume fraction parameter are presented graphically. The presence of slip and curvature parameters cause the region of dual solutions to expand and at once enhance the heat transfer rate at the surface but somehow the heat transfer rate at the surface decreases rapidly when cylinder is shrunk. The aim of this paper is to investigate the effect of slip parameter on nanofluid as well as on the stretching/shrinking surface. The new findings of the effects of skin friction and heat transfer coefficient on different nanoparticles and nanoparticle volume fraction were discussed. Since there are dual solutions in the flow characteristics, we carry out a stability analysis to verify which solution is in a stable state and can be realized physically. Full article

The study of biomagnetic fluid flow and heat transfer containing magnetic particles through an unsteady stretching/shrinking cylinder was numerically investigated in this manuscript. Biomagnetic fluid namely blood taken as base fluid and CoFe₂O₄ as magnetic particles. Where blood acts as an electrically conducting fluid along with magnetization/polarization. The main concentration is to study a time-dependent biomagnetic fluid flow with magnetic particles that passed through a two dimensional stretching/shrinking cylinder under the influence of thermal radiation, heat source and partial slip condition which has not been studied yet as far as best knowledge of authors. This model is consistent with the principles of magnetohydrodynamic and ferrohydrodynamic. The flow equations, such as momentum, energy which is described physically by a system of coupled, nonlinear partial differential equation with appropriate boundary conditions and converted into a nonlinear system of ordinary differential equations by using suitable similarity transformations. The resultant ODEs numerically solved by applying by applying an efficient numerical technique based on a common finite differencing method along with central differencing, tridiagonal matrix manipulation and an iterative procedure. The values assigned to the parameters are compatible with human body conditions. The numerous results concerning velocity, temperature and pressure field, as well as the skin friction and the rate of heat transfer, are presented for the parameters exhibiting physical significance, such as ferromagnetic interaction parameter, magnetic field parameter, volume fraction, unsteady parameter, curvature parameter, etc. The main numerical findings are that the fluid velocity is decreased as the ferromagnetic number is enhanced gradually in both stretching or shrinking cases whereas, the opposite behavior is found for the skin friction coefficient. The rate of heat transfer with ferromagnetic interaction parameter was also monitored and found that opposite behavior occurs for stretching and shrinking cases. Comparisons were made to check the accuracy of the present numerical results with published literature and found to be in excellent agreement. Hopefully, this proposed model will control the blood flow rate, as well as the rate of heat transfer, such as magnetic hyperthermia. Full article

The current analysis aims to exhibit the nanoparticles of Al₂O₃ + Cu-water hybrid nanofluid flow for Darcy–Forchheimer with heterogeneous–homogeneous chemical reactions and magnetic field aspects past a stretching or shrinking cylinder with Joule heating. This paper performed not only with the hybrid nanofluid but also the shape of Al₂O₃ and Cu nanoparticles. The model of single-phase hybrid nanofluid due to thermophysical features is utilized for the mathematical formulation. In the present exploration equal diffusions factors for reactants and auto catalyst are instituted. The system of governing equations has been simplified by invoking the similarity transformation. The numerical computations are invoked due to the function bvp4c of Matlab, with high non-linearity. Numerical outcomes illustrated that; sphere shape nanoparticles presented dramatic performance on heat transfer of hybrid nanofluid movement; an opposite behavior is noticed with lamina shape. The local Nusselt number strengthens as the transverse curvature factor becomes larger. In addition, the homogeneous–heterogeneous reactions factors lead to weaken concentration fluctuation. Full article

This numerical study was devoted to examining the occurrence of non-unique solutions in boundary layer flow due to deformable surfaces (cylinder and flat plate) with the imposition of prescribed surface heat flux. The hybrid Al${}_2$O${}_3$-Cu/water nanofluid was formulated using the single phase model with respective correlations of hybrid nanofluids. The governing model was simplified by adopting a similarity transformation. The transformed differential equations were then numerically computed using the efficient bvp4c solver with the ranges of the control parameters $0.5\%\le {\varphi }_1,{\varphi }_2\le 1.5\%$ (Al${}_2$O${}_3$ and Cu volumetric concentration), $0\le K\le 0.2$ (curvature parameter), $2.6<S\le 3.2$ (suction parameter) and $-2.5<\lambda \le 0.5$ (stretching/shrinking parameter). Dual steady solutions are presentable for both a cylinder $(K>0)$ and a flat plate $(K=0)$ with the inclusion of only the suction (transpiration) parameter. The real and stable solutions were mathematically validated through the stability analysis. The Al${}_2$O${}_3$-Cu/water nanofluid with ${\varphi }_1=0.5\%$ (alumina) and ${\varphi }_2=1.5\%$ (copper) has the highest skin friction coefficient and heat transfer rate, followed by the hybrid nanofluids with volumetric concentrations $({\varphi }_1=1\%,{\varphi }_2=1\%)$ and $({\varphi }_1=1.5\%,{\varphi }_2=0.5\%)$, respectively. Surprisingly, the flat plate surface abates the separation of boundary layer while it enhances the heat transfer process. Full article