Research progress on the preparation, rheological properties, and atomization characteristics of gel fuels

With increasing demand for high-safety, high-performance, and thrust-controllable fuels in aerospace propulsion systems, gel fuels have emerged as an important research focus. Gel fuels combine convenient transportability and flexible thrust controllability of liquid fuels with the high energy density and excellent storage safety of solid fuels. This review provides an overview of recent research progress on gel fuels within the framework of “preparation–microstructure–rheology–atomization,” emphasizing the relationships among preparation, rheology, and atomization. Firstly, it focuses on their preparation processes and gelation mechanisms. Secondly, it summarizes and analyzes the key non-Newtonian rheological properties of gel fuels, including shear thinning, yield stress, thixotropy, viscoelasticity, and extensional rheology. Thirdly, atomization represents a critical step in translating fundamental physical properties into practical engineering applications, as atomization quality can significantly influence combustion efficiency and propulsion performance. This review focuses on mechanical pressure atomization, pneumatic atomization, and auxiliary atomization technologies, providing a detailed account of gel fuel atomization characteristics and analyzing the core factors influencing atomization efficiency. Finally, it assesses the achievements and limitations of gel fuels and discusses future development trends. The aim is to provide guidance for the engineering application of gel fuels in aerospace propulsion systems.