Simultaneous Effects of Thermal Cycling and Shear on Flow Instabilities of Phase-Change Nanoemulsions Measured by Rheo-NMR and MRI Velocimetry.

ABSTRACT: Organic phase change materials (PCMs) for thermal energy storage can be emulsified in water in the presence of surfactants to enable their use as pumpable heat transfer fluids. However, PCM nanoemulsions often exhibit instabilities during thermal cycling and shear flow that limit their use. To investigate their combined effects, rheological nuclear magnetic resonance (rheo-NMR) spectroscopy and magnetic resonance imaging (MRI) velocimetry methods were applied on a model octadecane-water-stearic acid system. Rheology measurements indicated that the viscosity exhibited hysteresis during thermal cycling, which correlated with the solid fraction of octadecane. Fluid velocity profiles and concentration distributions of liquid octadecane were noninvasively measured in a Searle cell. Nonlinear fl

SUBMITTER: Park J 

PROVIDER: S-EPMC11973913 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature