Unifying perspectives on near-critical convective heat transfer at the microscale
University of Utah
Abstract
Near-critical fluids, particularly carbon dioxide (CO2), offer unique advantages for forced convection in microchannels, making them an increasingly compelling choice for compact, high-performance thermal systems. Their exceptional thermophysical properties—high heat transfer coefficients, low viscosity, and thermal stability—near the critical point enable efficient operation in applications ranging from renewable energy and waste heat recovery to aerospace and electronics cooling. However, the steep property gradients near the pseudocritical region, coupled with abnormal variations in density, specific heat, and thermal conductivity, present significant challenges in resolving flow behavior and accurately predicting heat transfer. This work combines high-speed schlieren imaging with microchannel heat transfer experiments to explore pseudocritical transitions, flow boiling dynamics, and the interplay between subcritical and supercritical regimes. By developing a unified mechanistic understanding for heat transfer in near-critical fluids, we address fundamental gaps in current understanding and provide critical insights for designing next-generation cooling technologies.
About the speaker
Dr. Sameer Rao is an Assistant Professor in the Department of Mechanical Engineering at the University of Utah. He studies both fundamental and applied problems related to heat and mass transfer, with an emphasis on transport processes as they relate to the micro- and nanoscale. He received his Ph.D. and M.S. in Mechanical Engineering from Rensselaer Polytechnic Institute in 2015, and Georgia Institute of Technology in 2012. Prior to joining the University of Utah in 2018, he worked at Massachusetts Institute of Technology as a postdoctoral researcher. He is the recipient of the University of Utah Early Career Teaching Award and has been recognized as a Presidential Societal Impact Scholar.
