NUMERICAL SOLUTION OF MELTING PROCESSES FOR UNFIXED PHASE-CHANGE MATERIAL IN THE PRESENCE OF ELECTROMAGNETICALLY SIMULATED LOW GRAVITY

Abstract

Electromagnetic simulation of low-gravity environment has been numerically investigated to study the transport phenomena associated with melting of an unfixed and electrically conducting phase-change material (PCM) inside a rectangular enclosure. Electromagnetic fields are configured such that the resulting Lorentz force can be used to damp and/or counteract the natural convection as well as the flow induced by sedimentation and/or floatation, thereby simulating the low-gravity environment of outer space. The governing equations are discretized using a control-volume-based finite-difference scheme. Numerical solutions are obtained for true low-gravity environment as well as for the simulated low-gravity conditions due to electromagnetic forces. The results show that when the Lorentz force is caused by the presence of magnetic field alone, the low-gravity condition is simulated by the magnetic 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 where the Lorentz force is caused by the transverse electric and magnetic fields, it is possible to minimize the flow field distortion caused by the high magnetic field and thereby achieve a much better simulation of low gravity.

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

Notes

∗ Melt thickness Y _G  = H∗ − Y _top, where H∗ is the height of the enclosure.