The heating and melting of reactive alloys in a cold crucible are considered in this study to produce a continuous melt stream as feed to a gas atomiser. A pre-heated rod of material enters the crucible at a rate equal to the amount of mass leaving as a liquid stream through the outlet. An induction coil is used to melt the contents of the crucible, which then pours out as a stream to enter a gas atomizer. The outlet nozzle may be controlled using an induction valve, operating at a different AC frequency. The concept is tested through simulations using titanium and a nickel superalloy as model materials. Tables 1, Figs 10, Refs 8.

The implementation of water electrolysis from lunar water sources facilitates the direct generation of hydrogen for rocket fuel and oxygen, which is essential for sustaining human life in space. Given the considerable costs associated with launching equipment into space, water electrolysis devices that operate in this environment must be smaller and lighter in order to be economically viable. This study proposes a pumpless water electrolysis device utilizing water-based ferrofluid. When non-magnetic hydrogen and oxygen bubbles are generated in a water-based magnetic fluid during water electrolysis under a non-uniform magnetic field, the balance of magnetic body force is disrupted, causing a driving force to act on the fluid. In this study, the driving force was experimentally verified using the PEM-type water electrolysis method. The findings have revealed that the proposed system can effectively function as a pump in removing the generated bubbles and self-supply water to the electrode. Tables 1, Figs 9, Refs 11.

A theoretical and numerical study on the dynamics of a spherical droplet of liquid metal in zero-gravity conditions in the presence of a uniform magnetic field is presented. The droplet is initially deformed into an ellipsoidal shape and then released so that it oscillates until it recovers a spherical shape. The strength of the applied magnetic field is modulated to analyze the damping process of the oscillating droplet. An analytical solution is obtained describing the free surface evolution of the droplet considering magnetohydrodynamic effects in the creeping flow regime. A numerical simulation of the oscillating droplet is implemented by solving the three-dimensional problem using the Smoothed Particle Hydrodynamics method. The analytical and numerical results agree qualitatively and quantitatively. Figs 5, Refs 10.

This work studies the convection phenomenon of two different fluids confined in a cubic cavity with a side length of 50 mm. Experiments with water and GaInSn eutectic alloy are conducted by heating and cooling the bottom and top lids, respectively. Temperature differences of 2, 4, 6, and 8 K are imposed between both lids to study convective flows. Particle image velocimetry and ultrasonic Doppler velocimetry techniques are used to measure water flows, whereas for GaInSn only ultrasonic Doppler can be used. Additionally, a numerical study was conducted using the ANSYS Fluent software. Experiments and simulations predict time-dependent flow patterns for both fluids. Maximum velocity values for water and GaInSn are up to 6 and 12 mm/s, respectively. Values for GaInSn are in the same order of magnitude as those obtained for electrovortex flows in the same configuration. Tables 1, Figs 10, Refs 26.

The emergence of hybrid carbon nanotubes presents a promising trend in enhancing heat transfer efficiency when compared to traditional fluids. This study delves into the innovation of employing hybrid carbon nanotubes in the context of a stretch/shrink sheet within the scope of MHD and slip parameter. To address this, the paper formulates partial differential equations governing the flow of a hybrid carbon nanotubes along with the pertinent boundary conditions, which are subsequently modified into ordinary differential equations. By employing similarity solutions and numerical techniques via bvp4c (MATLAB), the investigation examines the significances of MHD, both velocity and thermal slip, nanoparticle volume fraction and viscous dissipation influence on the local Nusselt number \Nux/√{\Rnx} and skin friction coefficient Cf√{\Rnx}. The findings reveal that the use of hybrid carbon nanotubes amplifies both Cf√{\Rnx} and \Nux/√{\Rnx} in comparison to single-wall and multi-wall structures. Accordingly, the response surface methodology is utilized to establish a correlation with the response of \Nux /√{\Rnx} and selected governing parameters. Tables 10, Figs 14, Refs 34.

A mathematical model of electrically driven laminar free shear flows in a straight duct under the action of an applied oblique transverse uniform magnetic field is considered. The mathematical approach is similar to that used in [1]. A system of stationary partial differential equations with two unknown functions of velocity and induced magnetic field is solved. Three different cases of electric current supply to the liquid are considered. An electric current is introduced into the liquid first by one pair of linear electrodes, and in two other cases by two pairs of electrodes located on the upper and lower walls of the duct. The cases are analyzed when the angle of inclination of the magnetic field vector to these walls is ϕ0 = π/4. Depending on the direction of the electric current supplied to the pairs of electrodes, two coinciding in direction or two opposite inclined flows are driven in the zone between these walls. Increasing the magnetic field only leads to an internal rearrangement of the flows. The Hartmann number Ha ranges from 1 to 10, at which MHD effects distinctly enough are already displayed. Figs 19, Refs 11.

We present a numerical investigation of the three-dimensional geometry effect on liquid metal flows in a rectangular duct subject to a transverse magnetic field using miniature cylinders immersed in fluid. Simulations are performed by means of a numerical method based on the finite volume method. The considered liquid metal is the 17Li83Pb eutectic alloy evolving in a rectangular channel. The influence of forced convection and magnetic field is studied. Streamwise counter rotating vortices are created in a spanwise direction by small devices intended for controlling the secondary flow near the wall region. It is found that the mushroom structure dominates in the flow at a low Reynolds number Reh ≤ 272. With a large Reynolds number, the flow regime is unstable downstream the duct showing horseshoe vortex patterns. By increasing the aspect ratio of the rectangular duct, the onset of steady streaks is delayed. Key words: Magnetohydrodynamics, liquid metal, numerical simulations, aspect ratio. Tables 1, Figs 8, Refs 26.

The present paper details a comparison of experimental and computational results for the electrovortex flow of mercury in cylindrical and semi-cylindrical vessels, which is driven by the direct electrical current supplied over top and bottom non-submerged electrodes. The time-averaged velocity of liquid metal computed using the LES model of turbulence qualitatively and quantitatively agrees with the measured profiles of the axial velocity for a cylindrical experimental setup. For a semi-cylindrical setup which represents possible ``cold'' physical modelling of MHD devices, the observed flow patterns at the free surface and the computed flow patterns also agree qualitatively. Tables 1, Figs 7, Refs 9.

The focus of this paper is a technical framework for studying thermomagnetic convection of ferrofluids in an extended closed loop that is a thin tube of circular cross-section. In the experiment, a short vertical section of the loop exposed to a nonuniform external magnetic field was heated. The remaining part of the loop was blown with a stream of thermostatic air to provide a constant heat transfer coefficient and an exponential temperature distribution along the tube. The damping decrement of the temperature perturbation was used to get information about the axial heat flux. Test experiments were performed with a colloidal solution of magnetite in moderately concentrated kerosene. It is shown that for Rayleigh numbers of the order of 103, the thermomagnetic convection mechanism causes a triple increase in heat transfer. Tables 1, Figs 8, Refs 16.

In this study we investigate the EM force and fluid velocity developed in a 2D liquid metal centrifugal system driven by a travelling magnetic field. A 2D axially symmetric numerical model has been developed using the COMSOL Multiphysics software, and distributions of pressure, azimuthal velocity and torque inside the centrifugal chamber were obtained. The average values for those distributions were successfully validated against a simple analytical model, showing that the presented numerical model can be used for a more in-depth analysis of the operating conditions of a centrifugal EM separator system. Keywords: centrifugal, electromagnetic, separator, velocity, numerical. Tables 1, Figs 16, Refs 5.