Identification of seal dynamic force coefficients for turbine rotor monitoring purposes

Abstract

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 their products performance and reduce the cost. In case of steam turbine, even slight improvement can bring high savings of money. One of the components which has significant influence on the turbomachine efficiency is the labyrinth seal. The increasing rotational speed and power and on the other side decreasing clearance between rotor and stator cause that seal forces 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 optimization. This paper is focused on identification of seal dynamic force coefficients based on experimental measurement. The experimental test rigs concepts are introduced as well as the identification procedure and methods. In addition, the concept of currently being built test rig with a rotor supported by active magnetic bearing is described in more detail.