Effects of Key Structure of Pressure Swirl Nozzle on Atomization Performance

The structure of the pressure swirl nozzle is the key factor affecting the atomization quality. Optimal design of nozzle structure is conducive to improving the atomization quality and has important significance for improving the efficiency and stability of the combustor. The effect of the swirl section diameter, the contraction section angle, the straight section diameter, and the expansion section angle on the spray cone angle and the liquid film thickness is studied by numerical simulation. The results show that the liquid film thickness and spray cone angle both decrease with the increase of the expansion section angle. As the straight section diameter increases, the spray cone angle and liquid film thickness both increased. Both the spray cone angle and the liquid film thickness have an optimal contraction angle value that is 60° and 45°, respectively. The increase in the ratio of the swirl section diameter to the straight section diameter can increase the liquid axial velocity. When the nozzle outlet has an expansion angle, the thickness of the liquid film is reduced. When the expansion section angle, the straight section diameter, the contraction section angle, and the swirl section diameter of the nozzle is 30°, 4 mm, 45°, and 12 mm, respectively, the atomization performance of this nozzle is the best.