Spray characteristics of gel containing nanoparticles in impinging jet injectors

Atomization is one of the critical challenges in the application of nanoparticle–laden gel propellants due to their high viscosity and complex rheological properties. This study investigates the rheological properties and atomization characteristics of gel containing varying concentrations of nanoparticles in impinging jet injectors. The rheological behavior of the gels was measured to characterize their shear-thinning properties. Impinging jet injectors with different structural parameters were designed and tested to evaluate the spray images, droplet size distributions, and discharge coefficients under various particle concentrations and flow conditions. Comparative analysis between water and particle–laden gels revealed that the high viscosity and complex rheological properties of gels hinder atomization, resulting in larger droplet sizes and reduced discharge coefficients. The results show that higher particle concentrations exacerbate these effects, but optimized injector design and increased jet velocity can mitigate the challenges by enhancing shear rates and reducing apparent viscosity. This study provides insights into gel formulation and injector design, offering practical guidance for advancing the application of gel propellants in propulsion systems.