Hartmann number

About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.

Mhd flow and heat transfer of two immiscible fluids between moving plates

Abstract: The magnetohydrodynamic (MHD) flow of two immiscible and electrically conducting fluids between isothermal, insulated moving plates in the presence of an applied electric and inclined magnetic field has been investigated in the paper. The partial differential equations governing the flow and heat transfer are solved analytically with appropriate boundary conditions for each fluid and these solutions have been matched at the interface. The numerical results for various values of the Hartmann number, the angle of magnetic field inclination, load parameter and the ratio of electrical and thermal conductivities have been presented graphically. It was found that decrease of magnetic field inclination angle flattens out the velocity and temperature profiles. With the increase of the Hartmann number velocity gradients near the plate’s increases, temperature in the middle of the channel decreases and near the plate’s increases. Induced magnetic field is evidently suppressed with an increase of the Hartman number. The effect of changes of the load factor is to aid or oppose the flow as compared to the short-circuited case.

Heat transfer and carbon nano tubes analysis for the peristaltic flow in a diverging tube

Abstract: Peristaltic flow model is recycled to study the influence of magnetic field on the flow and heat transfer of carbon nanotubes in a non-uniform tube. Two types of carbon nanotubes, namely, single- and multi-wall carbon nanotubes are postponed in water distinctly. The pragmatic associations are used for the thermo-physical properties of CNTs in terms of the solid volume fraction of CNTs. The governing equations are simplified using long wavelength and low Reynolds number approximation. Exact solutions have been obtained for velocity, pressure gradient, the solid volume fraction of the CNTs and temperature profile. The effects of various flow and heat transfer parameters, i.e., Hartmann number \(M\), the solid volume fraction \(\phi \) of the nanoparticles, Grashof number \(G_{r}\) and heat absorption parameter \(\beta \) are presented graphically.

Flow regimes of Rayleigh–Bénard convection in a vertical magnetic field

Abstract: The effects of a vertical static magnetic field on the flow structure and global transport properties of momentum and heat in liquid metal Rayleigh–Benard convection are investigated. Experiments are conducted in a cylindrical convection cell of unity aspect ratio, filled with the alloy GaInSn at a low Prandtl number of leaving only a near-wall convective flow that persists even below Chandrasekhar’s linear instability threshold. Our study thus proves experimentally the existence of wall modes in confined magnetoconvection. The magnitude of the transferred heat remains nearly unaffected by the steady decrease of the fluid momentum over a large range of Hartmann numbers. We extend the experimental global transport analysis to momentum transfer and include the dependence of the Reynolds number on the Hartmann number.

MHD natural convection of a hybrid nanofluid in an enclosure with multiple heat sources

Abstract: Natural convective flow and heat transfer of a hybrid nanofluid contained in an enclosure with multiple heat sources at the bottom wall are investigated in the presence of magnetic field applied to an angle with the horizontal axis. The system of equations is formulated systematically using dimensionless variables and parameters as well as defining stream function in terms velocity components. Solutions obtained by the finite difference method are then validated with experimental and numerical results which provides a good agreement. A grid independent test is also performed. Results reveal that flow pattern is substantially changed with the change of the magnetic field parameter, angle of magnetic field, number and breadth of heat sources and Rayleigh number. The intensity of the stream function is stronger for higher Rayleigh number and smaller magnetic field parameter. When the volume fraction of Cu nanoparticles is more than 6% the streamlines and isotherms demonstrate distinct pattern from those for its lower value. Moreover, symmetric pattern of streamlines is observed for angle of magnetic field equal to 0 and π/2. Due to the increase of the number of heat sources, angle of magnetic field and Rayleigh number, average Nusselt number is found to increase.