The Research of Dynamic Performance and Leakage for Finger Seal

• 1、Northwestern Polytechnical University
• 2、School of Mechanical and Electronic Engineering, Northwestern Polytechnical University

Abstract：The finger seal is a revolutionary new technology in turbine engines. Present researches indicate that the dynamic hysteresis and contact wear are two key problems in finger seal design. For these reasons, a dynamic model of finger seal system is presented for studying the above two problems. By using this model, the displacement response for finger seal and the contact pressure distribution between finger seal and rotor are obtained. According to the displacement response result, the dynamic leakage clearance for finger seal is obtained and the leakage is calculated subsequently. The results show preliminarily that: (1)the suitable interference not only reduce the response amplitude of finger seal but also decrease the phase-delay between the finger seal response and displacement excitation. On the other words, it makes the response of finger seal follow the motion of rotor better and reduce the leakage; (2)the contact pressure between finger seal and rotor change periodically with rotor running; (3) the maximum amplitude equal to the windage approximately after the rotor exceeding certain speed. This is mainly due to the rotor displacement excitation amplitude is constrained by the windage of rotor back-up bearing. The above results are validated by comparing with the test data in references. Therefore, this work may lead to a better design of finger seal.

Keywords： Finger seal Hysteresis Dynamic model Dynamic leakage