| dc.description.abstract | The labyrinth seal is widely used in turbomachinery to minimize or control
leakage between areas of different pressure. The present investigation numerically
explored the effect of damage and wear of the labyrinth seal on the turbomachinery
flow and temperature fields. Specifically, this work investigated: (1) the effect of rubgroove
downstream wall angle on seal leakage, (2) the effect of tooth bending damage
on the leakage, (3) the effect of tooth "€œmushrooming"€ damage on seal leakage, and (4)
the effect of rub-groove axial position and wall angle on gas turbine ingress heating.
To facilitate grid generation, an unstructured grid generator named OpenCFD was
also developed. The grid generator is written in C++ and generates hybrid grids
consisting primarily of Cartesian cells.
This investigation of labyrinth seal damage and wear was conducted using the
Reynolds averaged Navier-Stokes equations (RANS) to simulate the flows. The high-
Reynolds k - Model and the standard wall function were used to model the turbulence.
STAR-CD was used to solve the equations, and the grids were generated using
the new code OpenCFD.
It was found that the damage and wear of the labyrinth seal have a significant
effect on the leakage and temperature field, as well as on the flow pattern. The
leakage increases significantly faster than the operating clearance increase from the
wear. Further, the specific seal configuration resulting from the damage and wear was found to be important. For example, for pure-bending cases, it was found that the
bending curvature and the percentage of tooth length that is bent are important, and
that the mushroom radius and tooth bending are important for the mushrooming
damage cases. When an abradable labyrinth seal was applied to a very large gas
turbine wheelspace cavity, it was found that the rub-groove axial position, and to
a smaller degree, rub-groove wall angle, alter the magnitude and distribution of the
fluid temperature. | en |
