CAREER: Unveiling Liquid Droplet Entrainment and Heat Transfer Mechanisms in Two-Phase Annular Flow Boiling and Rewetting Using Advanced Laser-Based Diagnostics

Many energy and cooling technologies rely on boiling a liquid inside channels to remove large amounts of heat. Examples include nuclear power systems, advanced manufacturing, and electronics and data centers. Thin films of liquid form on the inside channel walls while fast-moving vapor occupies the interior of the channel. The details of liquid motion in the films can strongly affect rates of heat removal. The films can rupture in spots and then reform, which is called re-wetting. Small droplets of liquid can be ejected from the film and carried into the vapor, which is called droplet entrainment. These processes are difficult to predict in practice, even though they are important for heat removal. This CAREER project will use advanced visualization techniques to study re-wetting and droplet entrainment during flow boiling. The techniques will be able to resolve very fast processes at very small scales. The results will be used to develop models and heat transfer numerical tools that engineers can use to design efficient thermal systems. The project will also provide multidisciplinary research training for undergraduate and graduate students and broaden participation through education and outreach activities. This CAREER project will quantify droplet entrainment mechanisms during annular-film boiling and rewetting-front dynamics and develop first-principles models that link interfacial behavior to droplet formation and heat-transfer performance. The research will combine advanced laser-based visualization and measurement techniques to observe microscale liquid-film motion, temperature fields, interfacial waves, and droplet behavior under carefully controlled boiling and rewetting conditions relevant to advanced energy and thermal-management systems. Through statistically consistent data integration, physics-based theoretical models will describe how interfacial dynamics govern droplet formation, providing a foundation for improved engineering simulations of two-phase heat transfer. The project will create a predictive framework that connects microscopic interfacial physics to system-level thermal behavior, reducing reliance on empirical correlations and improving simulation reliability. The project will also train students in advanced experimental and data-analysis methods, develop an elective course on modern fluid diagnostics, conduct annual outreach activities for high-school students focused on energy and thermal science, and disseminate open datasets and educational resources through an online platform. Collaboration with federal regulatory stakeholders and national laboratories will help translate research outcomes to practical applications while strengthening workforce development in thermal-fluid science and engineering. 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. NSF Award ID: 2541125 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Yue Jin | Institution: University of Missouri-Columbia, COLUMBIA, MO | Award Amount: $566,915 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2541125 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2541125.html