Interlocking hole pattern seal

A method for reducing fluid leakage from a high pressure region to a low pressure region along a rotatable shaft, comprising:

• rotating the rotatable shaft, the rotatable shaft having an outer circumferential surface defining one or more annular protrusions;
• arranging a seal about the rotatable shaft, the seal having:
• an inner circumferential surface and one or more annular recesses, wherein the inner circumferential surface and the one or more annular recesses define a plurality of holes;
• and
• an annular groove defined in a side of at least one of the one or more annular recesses;
• and
• seating the one or more annular protrusions within the one or more annular recesses, whereby a tortuous flowpath is defined between the rotatable shaft and the seal for obstructing fluid leakage across the seal.

A seal assembly for a turbomachine, comprising:

• a rotatable shaft arranged within the turbomachine and having an outer circumferential surface defining annular protrusions that are axially-spaced from each other along an axial section of the rotatable shaft;
• a seal disposed about the rotatable shaft at the axial section and having an inner circumferential surface radially-offset from the rotatable shaft, the seal defining annular recesses extending radially-outward from the inner circumferential surface, and further having an annular groove defined in a side of at least one of the annular recesses, wherein each annular recess is configured to receive at least one of the annular protrusions, and wherein the inner circumferential surface and the annular recesses define a first plurality of holes;
• and
• a gap defined between the rotatable shaft and the seal, the gap providing a tortuous flowpath configured to impede working fluid leakage across the axial section from a high pressure side to a low pressure side.