A Novel Method Of Gradient Forming and Fluid Manipulation in Reduced Gravity Environments

The use of magnetic fields to control the motion and position of non-conductin g liquids has received growing interest in recent times. The possibility of using, the forces exerted by a non-uniform magnetic field on a ferrofluid to not only achieve fluid manipulation but also to actively control fluid motion makes it an attractive candidate for applications such as heat transfer in space systems. Terrestrial heat transfer equipment often relies on the normal gravitational force to hold liquid in a desired position or to provide a buoyant force to enhance the heat transfer rate. The residual gravitational force present in a space environment may no longer serve these useful functions and other forces, such as surface tension, can play a significant role in determining heat transfer rates. Although typically overwhelmed by gravitational forces in terrestrial applications, the body force induced in a ferrofluid by a non-uniform magnetic field can help to achieve these objectives in a microgravity environment. This paper addresses the fluid manipulation aspect and is comprised of results from model fluid experiments of the problem. Results from a novel method of forming concentration gradients that are applicable to low gravity applications are presented. The ground based experiments are specifically tailored to demonstrate the magnetic manipulation capability of a ferrofluid and show that gravitational effects can be countered in carefully designed systems.