Taguchi parametric analysis of the effects of electrode and magnetic actuator characteristics on Lorentz forces and heat transfer of a weak low-profile magneto-hydrodynamic blanket propulsion system

Parametric studies are conducted on different aspects of a planar MHD propulsion system called propulsive MHD blanket. Effects of nine different parameters on the electro-magnetic thrust, efficiency, and heat transfer of the blanket are investigated. To efficiently conduct the parametric analysis, the Taguchi test design method is used and 16 cases are defined. The Ansys-CFX commercial code is utilized as numerical solver and the obtained results are validated using the Hartman problem which indicated a negligible error of 0.16%. Electromagnetism, energy, mass, and momentum equations are considered for the fluid domain and heat transfer and electromagnetism equations are solved for the solid domain. On one hand, magnet shapes and type are found to be the highest effective parameters, followed by the electrodes voltage, length, and width. On the other hand, a prediction of the best combination of parameters for obtaining the highest electro-magnetic thrust are statistically accomplished which has produced an electro-magnetic thrust of 18.02 N per square meter for the MHD blanket which is twice the maximum electro-magnetic thrust obtained in the 16 initial test cases. It is demonstrated in the present paper that the unique applications of propulsive MHD blanket can compensate the very low efficiencies of MHD systems. It has also been shown that efficiency can be improved by enhancing the water conductivity, which is intended as a future study.

MAGNETOHYDRODYNAMIC HEAT AND MASS TRANSFER FLOW WITH INDUCED MAGNETIC FIELD AND VISCOUS DISSIPATIVE EFFECTS

An approximate solution to the problem of steady free convective MHD flow of an incompressible viscous electrically-conducting fluid over an infinite vertical isothermal porous plate with mass convection is presented here. A uniform magnetic field is assumed to be applied transversely to the direction of the flow, taking into account the induced magnetic field with viscous and magnetic dissipations of energy. The dimensionless governing equations are solved by using the series solution method. The induced magnetic field, current density, temperature gradient and flow velocity are studied for magnetohydrodynamic body force, magnetic Prandtl number, Schmidt number and Eckert number. It is observed that the induced magnetic field is found to increase with a rise in magnetic Prandtl number. Current density is strongly reduced with increasing magnetic Prandtl number, but enhanced with Schmidt number. The acquired knowledge in our study can be used by designers to control MHD flow as suitable for a certain applications such as laminar magneto-aerodynamics, and MHD propulsion thermo-fluid dynamics.

Induced magnetic field with radiating fluid over a porous vertical plate: analytical study

The objective of this investigation is to study the influence of thermal radiation and magnetic Prandtl number on the steady MHD heat and mass transfer by mixed convection flow of a viscous, incompressible, electrically-conducting, Newtonian fluid which is an optically thin gray gas over a vertical porous plate taking into account the induced magnetic field. The similarity solutions of the transformed dimensionless governing equations are obtained by series solution. It is found that, velocity is reduced considerably with a rise in conduction-radiation parameter (R) or Hartmann number (M) whereas the skin friction is found to be markedly boosted with an increase in M or Magnetic Prandtl number (Pm). An increase in magnetic body parameter (M) or Magnetic Prandtl number (Pm) is found to escalate induced magnetic field whereas an increase in R is shown to exert the opposite effect. Applications of the study include laminar magneto-aerodynamics, materials processing and MHD propulsion thermo-fluid dynamics.DOI: 10.3329/jname.v7i2.5662