Effect of tooth profile on the leakage and dynamic characteristics of labyrinth seals
The three-dimensional numerical analysis models of teeth-on-stator labyrinth seal(TOS LS),teeth-on-rotor labyrinth seal(TOR LS)and interlocking labyrinth seal(ILS)were established.The effects of four tooth profile angles(θ=0°,15°,30°,45°)on the leakage and dynamic characteristics of three labyrinth seals were investigated by applying multi-frequency elliptical whirling orbit model and computational fluid dynamics method.Under the operating conditions of 15 000 r/min rotational speed and 6.9 × 105 Pa inlet pressure,although ILS leaked the least,it was easy to cause rotor instability if the tooth profile angle was too small(θ=0°,15°);TOR LS had the worst sealing performance,while TOS LS had the best system stability.As the tooth profile angle increased from 0° to 45°:the leakage flow rate of TOS LS,TOR LS and ILS decreased by 5.6％,5.1％and 16.8％;the absolute value of negative flow-induced tangential force for the middle cavity increased by 60.2％,133.9％and 470.3％;the effective damping of the whole seal section increased by 44.9％-61.9％,30.7％-53.6％and 90.4％-445.3％,respectively,indicating the system stability was significantly enhanced.
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