Labyrinth seals are widely used in various types of turbomachinery due to their simple structure

convenient maintenance

and long service life. The shunt injection devices can reduce the flow-induced vibration caused by the spiral effect and improve the stability of the sealing system by affecting the circumferential flow inside the seal cavity. The three-dimensional numerical models of shunt injection labyrinth seal were established to calculate and analyze the impact of the shunt injection nozzle on the dynamic characteristics of the seal under different structural parameters. The results show that the smaller the tilt angle of the anti-swirl nozzle

the greater the system damping and stability. When the tilt angle is 30°

the effective damping is 4 times that of the vertical angle incident; the shape of the anti-swirl nozzle has a small impact on the sealing dynamic and flow characteristics.The cross stiffness of both nozzle hole types is negative

and the difference in cross stiffness between the two is about 5 kN/m at low frequencies and 1～2 kN/m at high frequencies; the more nozzles there are

the more they can suppress the circumferential flow of the rotor

which is beneficial for system stability.