[134] Identification of seal dynamic force coefficients for turbine rotor monitoring purposes

K Kalista, J Liska, J Jakl and V Vasicek

University of West Bohemia in Pilsen, NTIS – European Centre of Excellenc, Technicka 2, Plzeň 30614, Czech Republic
. Tel: 420 377 632 521; Email: kalistak@ntis.zcu.cz / jinliska@kky.zcu.cz / jjakl@kky.zcu.cz / vasicekv@ntis.zcu.cz 

Since rotating machines are all around us and provide excellent service, appropriate monitoring and knowledge is necessary for further improvements. Today, the main goal of all turbomachinery vendors is to improve the performance and reduce the cost of their products. In case of steam turbines, even a slight improvement can bring substantial cost savings. A component that has a significant influence on turbomachine efficiency is the labyrinth seal. The increasing rotational speed and power and decreasing clearance between the rotor and stator cause seal forces to excessively affect the rotor stability similarly to bearings. Special test-rigs are built to experimentally identify the seal dynamic force coefficients, which are then used for seal design optimisation. This paper is focused on the identification of seal dynamic force coefficients based on experimental measurement. The experimental test-rig concepts are introduced, as well as the identification procedure and methods. In addition, the concept of a test-rig currently being built with a rotor supported by an active magnetic bearing is described in more detail.