Thermophysical modeling for honeycomb-stator gas annular seal

Gas annular seals are commonly adopted for leakage control in turbomachinery applications. Honeycomb seals are attractive from the viewpoints of leakage control as well as rotordynamic stability. To improve our understanding of thermo-fluid-physics in such seals, a computational capability is developed for low Mach number, compressible, turbulent flows. The emphases of the present study include (i) development of an original numerical scheme with periodic boundary conditions for flows around repeated geometries, (ii) evaluation of a low Reynolds number version of the k-e turbulence model suitable for the operating conditions of honeycomb seals, and (iii) 3-D computations to assess the implications of the numerical predictions for practical configurations. It is demonstrated that for honeycomb seals, unsteady flow structures can be important. In terms of the loss mechanisms, contributions from both pressure-induced drag and wall shear drag are delineated. For honeycomb seals, the pressure-induced loss, resulting from the mixing process around the cells, is dominant over the wall shear loss.