NUMERICAL SOLUTION OF MELTING IN SIDE-HEATED RECTANGULAR ENCLOSURE UNDER ELECTROMAGNETICALLY SIMULATED LOW GRAVITY

ABSTRACT

Transport phenomena associated with melting of gallium inside a side-heated rectangular enclosure under electromagnetically simulated low-gravity environment has been numerically investigated. Electromagnetic fields are configured such that the resulting Lorentz force can be used to damp and/or counteract the natural convection and thereby simulate the low-gravity environment of outer space. The governing equations are discretized using a control-volume-based finite-difference scheme. The solutions are obtained for true low gravity as well as for the simulated low-gravity environment. The results show that when the Lorentz force is due to the presence of m2agnetic field alone, the low-gravity condition is simulated by the damping effect, which is shown to have a profound effect on the flow field. On the other hand, it is shown that under electromagnetic field simulation when the Lorentz force is caused by transverse electric and magnetic fields, it is possible to minimize the flow field distortion caused by the high magnetic field and therefore achieve a much better simulation of low gravity. Furthermore, it is found that under electromagnetic simulation of low gravity it is possible to achieve flow reversal when the electromagnetic force is greater than the gravitational force. More important, it is found that the flow reversal is preceded by a transition mechanism driven by thermoelectromagnetic convection, which leads to breakup of the natural-convection flow patterns.

Financial support for this work by NASA microgravity (grant NAG 32 434) is gratefully acknowledged.

Notes

*The minimum of the Ψ_max(Mp) curve can be shifted up or down depending on the values of B and ℰ. [i.e., Mp = fn(ℰ, B)], but it will never cross Ψ_max = 0.