动密封转子动力特性谐波激励实验测试方法

The development of the domestic advanced rotating seals technology is limited due to the lack of detailed experimental researches and reliable high-precision test rig. Therefore, in this paper, a high-precision rotordynamic characteristic test rig for rotating seals were built, and it is based on the wave excitation mechanical impedance method. The test rig includes five systems: air supply system, drive system, lubrication system, excitation system, and measurement system. During the test, two electromagnetic shakers were utilized to apply the single frequency or multi frequency harmonic excitation on the stator in both orthogonal (x- and y-) directions, and the force excitation signal, the response displacement and accelerated speed were synchronously measured, which can be used to finally solve force-displacement linear equation through the mechanical impedance of the uncompressed-gas benchmark decoupling test rig and the flow impedance of rotating seals and obtain the frequency-dependent rotordynamic characteristic coefficients of rotating seals. Utilizing the test rip, the frequency-dependent rotordynamic characteristic coefficients of rotating seals can be obtained under different operating conditions (including the inlet and outlet pressure ratio, rotational speed, inlet swirl speed, and eccentricity ratio), different sealing structures (non-contact rotating seals such as labyrinth seals, hole-pattern/honeycomb seals, and pocket seals) and different sealing clearances. In this paper, the detailed structure, measuring instrument and experimental principle of the test rig were described, and the leakage and rotordynamic characteristic were measured for a typical labyrinth seal which confirmed the feasibility and accuracy of the test rig.