This Small Business Technology Transfer (STTR) Phase I project will investigate turbulent flow of magnetic fluids (ferrofluids) used to enhance the cooling of oil-immersed electromagnetic devices such as power transformers. As an additive, an optimized ferrofluid will significantly extend the lifespans of millions of aging installed transformers. As a new technology, ferrofluid transformers will be smaller and possess improved dielectric capabilities. In Phase I, combined theory and experiments will develop the basics necessary for rational design of a ferrofluid transformer. Oscillating magnetic fields set the magnetic nanoparticles into rotation, the fluid's viscous stress tensor becomes asymmetric, and this gives the fluid unique cooling capabilities not seen with other fluids. A key objective will be to fundamentally understand the effect of the transformer's oscillating magnetic field on the nanoparticles. Anticipated results include identifying the relative contributions of the various terms describing the turbulent diffusion of spinning nanoparticles across magnetic field gradients and their wall boundary condition, and evaluating the viscosity and diffusion coefficients describing the interaction of the nanoparticles with surrounding fluid. Advances will be implemented into the first turbulent ferrofluid finite element CFD code. Phase II will model ferrofluid transformers prior to design evaluation, and eventual commercialization in Phase III. The electric industry is a $200+ billion industry, and ferrofluid technology is targeted squarely at this industry. Potential commercial applications of ferrofluids used for cooling include transformers ($300 million), voltage regulators, switching devices, and large motors and generators. In space, this technology may be used for magnetically driven convective cooling on the space station and on unmanned spacecraft. Additional applications include printers, optical devices, and medical.
