Flow Characteristics of Kerosene Gel in Different Injector Configurations

Gelled fuel combines the storage stability of solid-like materials and the flow adaptability of liquid-like substances, emerging as a crucial development in fuel technology for propulsion systems. However, the coupled thixotropic and shear-thinning properties of gelled fuel render its flow behavior inside nozzles highly complex, with the nozzle configuration directly affecting flow uniformity, pressure loss, and subsequent atomization efficiency. To reveal the regulatory aspects of typical nozzle configurations on the flow characteristics of gelled fuel, this study suggests a thixotropic shear-thinning constitutive model based on the "Carreau-Yasuda model + second-order kinetic equation". We carry out numerical simulations on the flow of 5% organic kerosene gel in three typical nozzle configurations (straight, converging, and tapered injectors). We investigate the effects of configuration parameters on the flow and the results show that the straight pipe nozzle only exhibits obvious structural breakdown in the wall region, while the gel in the core region maintains high structural integrity with insufficient viscosity attenuation;the converging nozzle can significantly enhance the shearing effect, accelerate the spatial homogenization of the gel's microstructural breakdown, and result in a more uniform viscosity distribution at the outlet section; the tapered injector acts as a localized deformation intensifier. Increasing the cone angle enhances shear localization, strengthens near-wall structural breakdown and viscosity reduction, but also shortens the residence time, leading to a competitive effect between shear intensity and residence time in the rheological evolution.