Dr. Xiulin Ruan is a Professor of Mechanical Engineering and a core faculty member of the Birck Nanotechnology Center at Purdue University. He is internationally recognized for transformative contributions to thermal transport science and engineering, spanning predictive theory, data-driven modeling, and scalable technologies with significant societal impact.
Dr. Ruan is widely regarded as a leader in phonon and photon transport, where his work has fundamentally advanced the understanding of heat conduction and radiation beyond traditional limits. He has made seminal contributions to the theory of four-phonon scattering, reshaping predictive models of thermal conductivity in solids and enabling accurate simulations across temperature and length scales. In parallel, he pioneered machine learning enabled approaches for thermal transport, establishing new paradigms for materials discovery and multiscale thermal design.
Beyond foundational theory, Dr. Ruan has demonstrated exceptional ability to translate scientific insight into high impact engineering technologies. He is the inventor of ultrawhite radiative cooling paints and coatings that passively reject heat to outer space, achieving record setting solar reflectance and thermal performance. This work culminated in the world’s whitest paint, recognized by the Guinness World Record, and has accelerated adoption of passive cooling solutions aimed at reducing building energy consumption and mitigating climate driven cooling demand. His innovations have received international recognition, including placement among TIME Magazine’s Best Inventions and major sustainability and innovation awards.
Dr. Ruan’s scholarly output features ten senior-authored papers designated as Highly Cited Papers by Clarivate Web of Science, among a body of more than 180 peer reviewed journal publications he has co-authored, reflecting sustained, field defining influence. He holds multiple issued and pending patents and has delivered over 100 invited lectures worldwide, shaping research directions across academia, national laboratories, and industry.
Equally significant is Dr. Ruan’s impact as a mentor and builder of the engineering workforce. He has trained over 45 graduate students, 11 postdoctoral researchers, and 9 visiting scholars, with 24 of them now holding faculty positions globally, extending his influence across generations of engineers and researchers. His leadership and mentorship have been recognized by multiple institutional and professional awards, including the ASME McDonald Mentoring Award.
Dr. Ruan is a Fellow of the American Society of Mechanical Engineers and served as an Associate Editor of the ASME Journal of Heat Transfer. His career reflects a rare combination of deep theoretical innovation, practical engineering impact, and sustained leadership.
