Digital modelling of annular seals dynamic behaviour

The work presents a method for analyzing the dynamic regime of labyrinth liquid seals. By using the traditional simplifying assumptions for the centered seal (sinusoidal, harmonically varying, first order pertubation), the approach can be addressed as 'quasi' 2D. A numerical coordinate transformation capable to treat displacement pertubations is introduced. The first order mathematical model is then deduced following the same steps as in previously published papers [1,2]. From this standpoint, the present method can be regarded as an extension of the above mentioned approaches that were able to deal only with stator-grooved seals. The method is validated by comparisons with Nordmann and Dietzen's [3] theoretical results for a seal with grooves on both stator and rotor and with the experimental results of Staubli's [4] test case concerning a general seal.