SPRAY CHARACTERISTICS OF GEL PROPELLANTS IN OPEN-END SWIRL INJECTOR

Gel propellants, which behave both liquid and solid propellant characteristics, have broad application prospects. Gel propellant is a kind of power-law fluid, and its high viscosity and difficulty in atomization have restricted its application in the aerospace field. Open-end swirl injectors can be combined with other nozzles to form gas-liquid coaxial nozzles. At present, there are few studies on the application of gel propellants to open-end swirl injectors. A set of gel simulant spray system was set up to investigate the spray characteristics of gel propellants in open-end swirl injector. Three kinds of gel simulants with different rheological parameters were used. Three open-end swirl injectors with different tangential channel diameters were designed to change the geometrical characteristics constant A of the swirl injectors. The thickness of the liquid film in the open-end swirl injectors and their spray characteristics were experimentally studied. The liquid film thickness of the gel propellant was measured by the conductance method. The details of the liquid film break-up and spray development were recorded using a high-speed camera. The effects of the above rheological and geometrical parameters on liquid film thickness, discharge coefficient, spray cone angle and liquid film breakup length, etc. were obtained, and the empirical equations were summarized.