Superhydrophobic Particle Ejections from Liquid Surfaces in Microgravity Environments

Abstract

This paper explores a completely new avenue of microgravity fluidics that has not been systematically studied before, exploring superhydrophobic particle ejections from liquid surfaces in microgravity environments and quantifying the particle velocity varying particle. Superhydrophobic surfaces greatly reduce liquid-substrate contact. This allows for spontaneous ejection of floating particles in drop tower experiments. To quantify such phenomena, a drop tower experiment is constructed and tested. The Dryden Tower (DDT) is a laboratory facility at Portland State University that allows for the investigation of short duration exploration and research on Earth of 'micro-gravity' phenomena similar to that aboard orbiting spacecraft. Perhaps surprisingly, this short 2.1 second period of weightlessness during free fall provides ample time for many fluids, combustion, and materials science investigations. This study employs large superhydrophobic spherical particles of varying masses of the spheres to determine ejection velocities. Simple energy analysis is shown to provide fair agreement with the experimental results.