Recently, Prof. Chengming He, a Jinshan Distinguished Young Professor at Jiangsu University, together with Associate Professor Peng Zhang from City University of Hong Kong and Professor Chung K. Law from Princeton University, has published a review paper titled "Dynamics of binary droplet collisions" in the energy-related top Journal Progress in Energy and Combustion Science. Jiangsu University is the first completion affiliation, and it is also the first time for Jiangsu University to publish an article in this top energy journal.
Binary droplet collisions are closely related to various natural phenomena and industrial processes, covering a wide range of disciplines from atomic physics to atmospheric environments, from engine spray combustion to biopharmaceutical engineering and additive manufacturing, etc. It embodies a rich fluid-dynamical platform covering a wide range of physical scales, in which the complex physical mechanisms such as nonlinear dynamics, interface mechanics, and molecular interaction mechanics are crucial for controlling droplet aggregation to optimize reaction processes and precisely regulating droplet collision behavior. This review begins with the collision between two identical droplets to reveal the underlying physics of the transition between droplet coalescence, bouncing, and separation. The interplay between the macroscopic droplet motion, the internal flow, and the microscopic interfacial gas film dynamics involving rarefied flow and van der Waals molecular force reflect the essential multi-scale and multi-physics characteristics of the collision dynamics. The review then discusses the collision between unequal-sized droplets, non-Newtonian fluids, dissimilar fluids, and the analogical jet-jet collisions. Fundamental understanding on the basic binary droplet collisions phenomena and its inference on practical processes is emphasized. The multi-scale and multi-physics mechanisms of droplet collisions provide a theoretical framework for the cross-scale fluid dynamics research.
The Spray Combustion and Energy Utilization Team, where He Chengming is located, has been dedicated to the research on low-carbon and zero-carbon fuel spray combustion in power systems and the efficient and clean utilization of energy. Adhering to the "four-cross" team spirit of Professor Li Detao, the team attaches great importance to international cooperations, the integration of universities and enterprises, and cutting-edge basic theoretical research in the field of cross-disciplinary frontiers. The team conducts fundamental theoretical research on micro-scale, ultra-high-speed, strong transient cavitation two-phase flow, spray droplet dynamics, spray multiphase flow and micro-macro-scale flow and heat transfer of advanced energy catalytic materials, as well as combustion reaction kinetics. At the same time, they actively carry out the research and development of high-end equipment for fuel injection systems in vehicle, ship, aerospace, and defense power systems.
This research was funded by the National Natural Science Foundation of China.
Over the past 50 years since the establishment of Progress in Energy and Combustion Science Journal in 1974, only 30-40 articles are published each year, and the total number of papers published by Chinese research institutions as the corresponding (or first) author units in this journal is less than 50. (Energy Research Institute).
DOI：https://doi.org/10.1016/j.pecs.2025.101252
