CAREER: Probing Extreme Limits of Phase Change Heat Transfer via In-situ Optical Metrology

Liquid-vapor phase change is a transition of material from liquid to gas state or gas to liquid state. Liquid-vapor phase change underlies evaporation, boiling, and condensation, which are important in many applications such as power generation, chip cooling water purification, and air conditioning. Heat transfer in these applications is ultimately determined by microscopic processes at liquid-vapor interfaces. Although heat transfer across an entire system undergoing liquid-vapor phase change can be measured at macroscopic scales, probing the nanometer-thick liquid-vapor interface is challenging. This CAREER project will use a combination of advanced experimental methods and modeling to measure heat transfer at the liquid-vapor interface. Results from the project will help create design rules for high-performance phase change systems. The project will also create hands-on projects for engineering teaching, host undergraduate researchers, and engage the public through science and technology workshops. This project will develop a mechanistic understanding of heat transfer across liquid-vapor interfaces through a deep integration of high-fidelity multiscale simulation and high-resolution optical metrology. A multiscale modeling framework will be established to precisely model intrinsic properties of the liquid-vapor interface from first principles, bridging the critical knowledge gap between microscopic quantum-mechanical interactions and macroscopic heat transfer characteristics. Non-invasive, in-situ optical metrology, including interferometric scattering microscopy and confocal micro-Raman thermometry, will be used to measure heat flux and temperature difference across the nanometer-thick liquid-vapor interface with unprecedented accuracy and spatial resolution. By combining multiscale modeling with in-situ characterization, this project will elucidate the molecular origin of interfacial thermal transport, thereby establishing a complete physical picture for the extreme limit of phase change heat transfer. Insights gained from this project will provide a roadmap toward this extreme limit, enabling the design of highly efficient liquid-vapor phase change systems. The in-situ optical metrology and quantum simulation methodologies developed in this project will serve as a general platform for understanding various thermofluidic phenomena. 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: 2542685 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Lenan Zhang | Institution: Cornell University, ITHACA, NY | Award Amount: $500,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2542685 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2542685.html