Guo's work has been focused in
thermofluid mechanics,
heat transfer processes at the micro and nano scales, optimization of
thermodynamic systems, and more efficient thermal transport.[2] In 1994 he introduced the concepts of thermal drag, thermal drive, thermal displacement, and
thermal instability, which use analogies to mechanical systems to describe properties in thermal systems.[3]
Thermomass theory models
heat transfer as a gas-like flow from heat carriers, caused by a
pressure gradient. In this framework, heat has a dual nature, acting as mass during transfer and as energy during transformation.[2] This approach has been applied, for example, in modeling heat conduction in
nanosystems, where non-local, non-linear effects not fully accounted by
Fourier's lawheat equation and by the
Maxwell-Cattaneo-Vernotte equation are more significant.[4][5]
The concept of entransy, developed by Guo's group, is based on an analogy between
electrical conduction and heat conduction. Their work in "Entransy dissipation in
heat exchangers" was included in the top 10 research fronts in mathematics, computer science and engineering by
Thomson-Reuters in 2014.[7]
The concept of entransy has been accused of plagiarism as well as criticized for being incorrect and a hoax, by
Adrian Bejan and others, with
Milivoje Kostic writing a critical perspective on the issue.[8]