Turbine abradable layer with progressive wear zone terraced ridges

A method for reducing turbine engine blade tip wear, comprising:

• providing a turbine having a turbine housing, a rotor having blades rotatively mounted in the turbine housing, distal tips of which forming a blade tip circumferential swept path in the blade rotation direction and axially with respect to the turbine housing;
• inserting a generally arcuate shaped abradable component in the housing in opposed, spaced relationship with the blade tips, defining a blade gap there between, and the abradable component having:
• a support surface for coupling to the turbine casing;
• an abradable substrate surface on the support surface facing the blade tips, having a surface profile conforming to the swept path and, having at least one stepped cross sectional profile first ridge projecting from the substrate surface, the first ridge having:
• a first portion proximal the substrate surface with a pair of first opposed lateral walls terminating in a plateau having a first cross sectional width;
• a second portion, defined by a pair of second opposed lateral walls terminating in a ridge tip and having a second cross sectional width smaller than the first cross sectional width;
• and
• first and second corresponding walls on at least one side of the ridge laterally offset from each other by the plateau;
• and
• operating the turbine engine, so that any contact between the blade tips and the abradable surface initially abrades the second portion of the substrate first ridge, so that the first portion of the first ridge inhibits turbine gas flow between the blade tips and substrate surface without rubbing the blade tips.

A turbine engine, comprising:

• a turbine housing;
• a rotor having blades rotatively mounted in the turbine housing, distal tips of which forming a blade tip circumferential swept path in the blade rotation direction and axially with respect to the turbine housing;
• and
• an abradable component having:
• a support surface coupled to and circumscribing at least an inside portion of the turbine housing;
• and
• an abradable substrate coupled to the support surface, having a substrate surface aligned proximal the blade tip circumferential swept path;
• and
• a plurality of stepped cross sectional profile first ridges projecting from the substrate surface toward the turbine blades, each ridge having:
• a first portion proximal the substrate surface with a pair of first opposed lateral walls terminating in a plateau having a first cross sectional width;
• and
• a second portion, defined by a pair of second opposed lateral walls terminating in a ridge tip and having a second cross sectional width smaller than the first cross sectional width;
• and
• first and second corresponding walls on at least one side of the first ridge laterally offset from each other by the plateau.