异形孔腔结构对液体孔型密封泄漏特性及转子耗功的影响

To reduce the leakage and increase the aerodynamic efficiency and rotor stability of turbomachinery, five hole seals with odd-shaped geometrical structures including a ball-shaped concave cavity, two circumferentially oblique hole geometries and two axially oblique hole geometries were presented based on the typical hole-pattern seal model. A steady numerical approach was used to investigate the influence of odd-shaped hole geometry on the leakage performance and rotor drag torque of hole-pattern seals. The leakage flow rate, cavity flow field, turbulent kinetic energy dissipation rate and the rotor drag torque were calculated and analyzed for the six hole seals (one typical hole seal and five odd-shaped hole seals) with different hole geometries at various rotational speeds (0, 2 000, 4 000, 6 000 r/min). Results showed that compared with the typical hole-pattern seal, the ball-shaped concave cavity can markedly reduce the leakage flow rate at the rotational speed range from 0 to 4 000 r/min; circumferentially oblique holes can obviously decrease the circumferential swirl velocity in the seal gap. The circumferentially oblique hole with an oblique angle α=30° has the minimum leakage flow rate, and the axially oblique hole results in a slight decrease in the rotor drag torque. The axially oblique hole with an oblique angle β=20°can reduce the leakage flow rate. Contrarily, the axially oblique hole with an oblique angle β=-20° results in an increase in leakage flow rate.