EXPERIMENTAL VALIDATION OF A SEAL FLUTTER MODEL

Abstract In this paper, the predictions of an analytical model for seal flutter have been compared with the experimental data of a rotating multi-cavity labyrinth seal test rig. The experiments were conducted to assess the flutter inception in a large set of operating conditions by varying the rotational speed and the total pressure ratio across the seal. The analytical model derived by Corral et al. (2022, “Effective Clearance and Differential Gapping Impact on Seal Flutter Modelling and Validation,” ASME J. Turbomach., 144 (7), p. 071010) has been previously validated by using a frequency domain linearized Navier–Stokes solver retaining the effect of the effective gaps and the kinetic energy carried over to the downstream fin. A set of 3D steady RANS simulations has been carried out to reduce the uncertainty in the steady characteristics of the seal that are used to inform the flutter model. The simulations consider the static deformation due to the pressure and the centrifugal force through a set of numerical models with geometrical gap differences. The stability has been investigated in a large range of operating conditions. It is concluded that the analytical model can be used to quickly predict the modes susceptible to flutter, provided that the steady flow field and the effective running clearances of the seal are well predicted.