Visualization of Flow Field of Temperature-sensitive Magnetic Microcapsule Dispersion

Abstract

　　　Heat transport devices using temperature-sensitive magnetic fluids are fast to start, have high heat transfer efficiency, and can be downsized. In addition, it has the advantage that it is not affected by the installation posture compared to conventional heat transport equipment. In order to apply a temperature-sensitive magnetic fluid to a heat transport device, it is necessary to clarify the heat flow characteristics of this fluid. However, since the ferromagnetic particles in the fluid are black and fine, observation with a microscope was difficult. In this study, the microcapsules contain a temperature-sensitive magnetic fluid, which enables fluorescence observation. Capsules were made by mixing a temperature-sensitive fluid, polymer, organic solvent, and fluorescent dye and dispersing in pure water mixed with a surfactant. Microcapsule aqueous solutions have been shown to have properties similar to magnetic fluids. When this solution was flowing, it was confirmed that when a magnetic field was applied, clusters were formed near the wall and a unique velocity distribution was formed. It was confirmed that as the solution temperature increased, the possibility of cluster formation decreased.