Dielectric nanofluids for electrostatic machines

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Increases in the nation's population have created an unprecedented demand for electric motors in conventional and emerging technologies. New uses of electricity, including electric vehicles, server farms to support the internet, and high-speed rail, have contributed additional demands for electric motors. Furthermore, direct drive wind turbines and drones could benefit from reconfigurations of their drive trains. Conventional electromagnetic motors utilize rare earth elements such as dysprosium and neodymium whose future availabilities are uncertain. Electrostatic motors can be made sustainably, but improvements in torque output are required for many applications. Increased torque can be achieved by increasing the dielectric constant of the fluid within the motor. Adding small particles can increase the fluid's dielectric constant, but the particle-fluid mixture can become too viscous for motor applications. In this project, mathematical models and computer simulations will be used to engineer particle-fluid mixtures that have high dielectric constants and low viscosities. The research team will partner with the University of Wisconsin's Institute for Chemical Education to guide undergraduate students in constructing demonstrations of electrostatics intended for K-12 students. The demonstrations will be used at various venues to engage the public in novel applications of electrostatics. The large electric fields required for electrostatic motors can cause field-induced aggregation of the particles in the suspension within the motor. Aggregation of the particles leads, in turn, to large increases in the suspension viscosity, which diminishes motor performance. Particle aggregation can be avoided by employing Brownian nanoparticles in the suspension, such that thermal motion can overcome the field-induced forces. Aggregation of the particles due to van der Waals forces can be avoided by steric stabilization. Particle-level simulations will be employed to determine the relationships between particle size and concentration, electric field strength and frequency, steric layer properties, and the macroscopic dielectric and rheological properties of the suspensions. The results of this work will enable practitioners to engineer effective nanoparticle suspensions for a variety of electrostatic motor applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.