Influence of honeycomb rubbing on tip seal performance of turbine rotor

The small radial gap of the rotor tip seal leads to the rubbing of a honeycomb in take-off conditions and the leakage flow increases in the cruise conditions. The aim of this study is to compare two honeycomb seal configurations of low pressure gas turbine rotor. In the first configuration the gap is small and a rubbing takes place. In the second the fins of the seal are shorter to eliminate the rubbing. The study of geometrical model of honeycomb was performed to reduce the computational effort. The problem was investigated numerically using RANS equations and the two-equation SST turbulence model. The full honeycomb structure was taken into consideration to show details of fluid flow. The main parameters in the gap and leakage flows were compared and discussed. The assessment of leakage flow through the seal variants could support a design process.