Analysis of the impact of mass flow extraction on the change of parameters in a labytinth seal using the Stodola method

Labyrinth seals are an important element of a steam turbine set design. The use of diagnostic extraction makes it possible to control the operation of a seal by providing information on the thermodynamic parameters along the length of the seal. Diagnostic extraction has a considerable impact on the change of the parameters, the amount of the extracted mass. This article describes the dependence of pressure in the clearance downstream of the extraction and in the chamber in which the extraction point is located, on the amount of the extracted steam. Relation between pressure and nominal seal clearance is discussed, which enables the control of the seal operation. The calculations of the seal operation parameters were performed using a method proposed by Stodola.