Spray characteristics of the nanoparticle-containing gel propellants by using an improved single-phase nozzle

Due to the high viscosity and complex rheological properties, the atomization problem continues to be one of the key problems of gel propulsion technology. By analyzing the rheological properties of the gel propellants containing nanoparticles, an improved single-phase nozzle was proposed in this manuscript, which added a cone-like structure inside the nozzle. The equivalent cross-sectional area of propellant passage decreases gradually from inlet to outlet, which ensures that the apparent viscosity of gel propellant decreases continuously until it flows out of the nozzle. A series of experiments were conducted to investigate the atomization characteristics of the improved nozzle. A traditional direct current (DC) nozzle was also used for comparison. The results showed that the improved nozzle proposed in this manuscript can effectively improve the atomization fineness and uniformity of the gel propellant containing nanoparticles by efficiently decreasing Sauter mean diameter (SMD) and also reducing the volume fraction of large droplets in the spray field. Meanwhile, the spray cone angle of the improved nozzle was obviously larger than that of the DC nozzle, which was favorable for mixing and evaporation in the thrust chamber.