Turbine abradable layer with progressive wear zone multi level ridge arrays

A method for reducing turbine engine blade tip wear in 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, the method comprising;

• inserting a generally arcuate shaped abradable component in the housing in opposed, spaced relationship with the blade tips, defining a blade gap there between, the abradable component having:
• a support surface for coupling to the turbine casing;
• an abradable substrate coupled to the support surface having a substrate surface adapted for orientation proximal a rotating turbine blade tip circumferential swept path;
• alternating rows of opposed, continuous elongated first and second ridges spanning at least sixty percent of and projecting from the substrate surface, the first ridges having a first ridge height greater than second height of the second ridges;
• operating the turbine engine so that upon any contact between the blade tips and the abradable surface initially abrades only higher first ridges tips while remaining non abraded first ridges and the second ridges inhibit blade tip gas flow between the blade tips and substrate surface;
• and
• operating the turbine engine such that upon any subsequent contact between the blade tips and the abradable surface abrades remaining portions of the first ridges or the second ridges.

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 for coupling to a turbine casing;
• an abradable substrate coupled to the support surface, having a substrate surface adapted for opposed, spaced orientation proximal a rotating turbine blade tip circumferential swept path;
• and
• alternating rows of opposed, continuous elongated first and second ridges spanning at least sixty percent of and projecting from the substrate surface, the first ridges having a first ridge height greater than second ridge height of the second ridges;
• wherein the first ridge height is selected such that a first travel of the distal tips into a path of the abradable surface results in abrading of the first ridges only;
• and
• wherein the second ridge height is selected such that a subsequent travel of the distal tips into a path of the abradable surface results abrades any remaining first ridges, if present, and subsequently abrades at least one of the second ridges.