Numerical investigation on effect of geometrical parameters and rotor speed on leakage flow of gas turbine brush seal

In this paper a two-dimensional axisymmetric CFD model is used to investigate the effect of bristle pack free length (the distance between bristle pack tip and front plate), fence height (the distance between backing ring and bristle pack tip), bristle pack thickness and clearance (the gap between rotor surface and bristles tip) on leakage flow of brush seals using Reynolds-Averaged-Navier-Stokes (RANS) and non-Darcian porous medium approach.The results show, the leakage flow decreases with increasing the bristle pack thickness and decreasing the fence height while there is almost no change in leakage flow, when increasing the bristle pack free length. The leakage flow of the brush seal increases with increasing the clearance. This work demonstrates that in order to have the minimum leakage, fence height and clearance should have their minimum values and bristle pack thickness should be increased. Moreover, the effect of rotor speed on leakage flow is investigated. As results indicate, increasing the rotational speed leads to a slight decrease in leakage flow.