Tooth Thickness Effect on the Performance of Gas Labyrinth Seals

A previously validated finite difference computer code was revised to allow the specification of upstream and downstream reservoir conditions as boundary conditions, whereas the domain extends only from the seal inlet to outlet plane. As a result of this special revision, the required execution CPU time is approximately only one hour on a VAX 8650 computer for three-cavity, straight-through seals. A parametric study focusing on tooth thickness showed that streamwise swirl development was only slightly higher for the thickest tooth. Further, for straight-through seals it was found that leakage is almost independent of tooth thickness and that the second cavity yields a definite increase in turbulence energy and turbulence length scale over the first cavity.