交错式迷宫密封动力特性系数实验识别

Experimental Identification for Rotordynamic Coefficients of the Interlocking Labyrinth Seal

设计搭建密封动力特性实验识别装置,基于阻抗法对交错式迷宫密封动力特性系数开展实验识别,并与数值计算结果进行对比。结果表明:数值计算的结果整体上略小于实验识别的交错式密封动力特性系数,但随涡动频率变化趋势上具有良好吻合性,应用阻抗法可有效识别密封动力特性。实验与数值计算所得交错式迷宫密封直接刚度系数恒为负值,存在静态不稳定问题;有效阻尼在低频时为负值,其绝对值同进口压力及转速正相关,中高频激励时转为正值,随涡动频率变化较为稳定。

An experimental device was designed to obtain the dynamic characteristic coefficients of the interlocking labyrinth seal based on the impedance method. The numerical results were compared with the experiment test. Results show that the dynamic coefficients from experiments are slightly larger than that from the numerical calculation on the whole,but the overall trend agrees well. The impedance method can be a proper means to identify the dynamic characteristics of the seal. The experimental results also show that the direct stiffness of the interlocking labyrinth seal is negative at all test frequency domain, which may cause static instability. In addition, the effective damping is negative at low frequencies,and it decreases with the increasing inlet pressure and rotational speed. It turns out to be positive with growing whirling frequency, and it is relatively stable with the varying whirling frequency.