Numerical simulation and analysis of leaf seal leakage flow

Leakage flow field of leaf seal, seal performance and its influential factors were analyzed based on its structure feature, and fluid dynamics calculative model of sealing zone was built. The velocity, pressure distribution in sealing clearance and leakage were calculated, and the sealing performance with structure parameters in different working conditions was obtained. The result shows that the leakage increases linearly with the sealing pressure, and decreases slightly with the increase of rotor speed; leakage reduces by about 40% with the leaf width from 3 mm to 7 mm, while it increases by only about 8% with the leaf length from 12 mm to 16 mm. With the widening gap of the front/back cover plate to leaf or to rotor, the result is also different; the gap from upper cover plate to rotor has greater impact on leakage compared with lower cover plate, with the leakage up to 16%. Leakage and rotor force are also affected by different dip angles of the leaf end.