ISS: FREEZING DYNAMICS OF SESSILE DROPS IN MICROGRAVITY

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

Freezing of drops on cold surfaces or Sessile-drop freezing (SDF) is ubiquitous in the natural and industrial world, impacting various applications such as icing on surfaces, freeze casting, and desalination. The presence of solutes like salt, organic materials, or particles within the water can significantly influence freezing behavior. While pure water droplet freezing has been extensively studied, there is limited understanding of how solute-laden droplets freeze, especially under microgravity conditions found in space. This research will focus on understanding how solutes affect the freezing of water droplets in the International Space Station (ISS) microgravity environment. By eliminating the effects of gravity, this work aims to gain clearer insights into the fundamental processes. This research could lead to significant advancements in our understanding of freezing dynamics, with potential benefits including developing better anti-icing coatings, improved manufacturing processes using freeze casting, improved methods for desalinating impure water using freezing, and enhanced models for ice formation in the environment. This project also aims to foster educational opportunities for undergraduate students, particularly those from underrepresented communities, by engaging them in hands-on experimental and computational work, thereby cultivating a diverse and skilled workforce equipped to tackle future scientific and engineering challenges. This award aims to elucidate the roles of gravity on the freezing dynamics of sessile drops in the presence of soluble and insoluble particles. This project involves several key tasks: fabricating samples and solutions for ISS experiments, coordinating with NASA implementation partners to prepare the experimental rig, overseeing test runs and final experiments at the ISS, and conducting thorough data analysis. Additional tasks include obtaining on-ground SDF results with varied surface orientations and performing phase-field simulations to understand freezing dynamics, shape evolution, solute segregation, and solutal Marangoni flows inside droplets with and without gravity. Advanced characterization techniques, such as optical/infrared imaging, micro-computed tomography, and computational studies, will enable a comprehensive analysis of these phenomena and the development of accurate freezing models. The research outcomes are expected to inform the development of novel anti-icing coatings, advance manufacturing processes like freeze casting, and create new freezing desalination systems. The high-quality experimental data from the ISS will also help improve existing freezing models. 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.