# US 2013/0156578 A1 · Compressor airfoil tip clearance optimization system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156578 A1 - Document ID: US20130156578A1 - Status: Published application - Kind: A1 - Application number: 13/326,399 - Filed: 2011-12-15 - Published: 2013-06-20 - Earliest claimed: 2011-12-15 - Assignees: Siemens Energy, Inc. - Inventors: David A. Little; Zhengxiang Pu - Web page: https://patentgrep.com/patent/US20130156578A1 ## CPC - F04D 29/164: {of an axial flow wheel} - F04D 19/028: {Layout of fluid flow through the stages} - F04D 29/052: Axially shiftable rotors (F04D29/051 takes precedence {; control by creating a by-pass F04D27/0246}) - F04D 29/522: {especially adapted for elastic fluid pumps} - F01D 11/22: by mechanically actuating the stator or rotor components, e.g. moving shroud sections relative to the rotor - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) ## Abstract A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine. ## Claims ### Claim 1 A compressor airfoil tip clearance optimization system for increasing efficiency of a turbine engine by reducing the clearance between a tip of a compressor airfoil and a radially adjacent component of the turbine engine, comprising: at least one generally elongated blade having a leading edge, a trailing edge, the tip section at a first end, and a root coupled to the blade at an end generally opposite the first end for supporting the blade and for coupling the blade to a disc of a rotor assembly; at least one generally elongated compressor vane affixed to a stationary component such that the at least one generally elongated compressor vane does not rotate with a rotor assembly during turbine engine operation; an ID flowpath boundary extending from generally an upstream end of a compressor to generally a downstream end of the compressor, wherein the ID flowpath boundary is formed in part from a compressor rotor assembly; an OD flowpath boundary extending from generally the upstream end of the compressor to generally the downstream end of the compressor, wherein the OD flowpath boundary is formed in part from a compressor casing; at least one clearance reduction system configured to move the rotor assembly axially to reduce tip clearance of the at least one generally elongated blade and the at least one generally elongated compressor vane; wherein the ID flowpath boundary increases in distance radially outward from a longitudinal axis when moving axially downstream in a direction from the upstream end to the downstream end. ### Claim 2 (depends on 1) A compressor airfoil tip clearance optimization system of claim 1, wherein the OD flowpath boundary is generally aligned with the longitudinal axis of the compressor in an axial direction. ### Claim 3 (depends on 1) A compressor airfoil tip clearance optimization system of claim 1, wherein the OD flowpath boundary increases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially downstream section formed from less than 40 percent of an axial length of the compressor extending upstream from the downstream end of the compressor. ### Claim 4 (depends on 3) A compressor airfoil tip clearance optimization system of claim 3, wherein the OD flowpath boundary upstream of the axially downstream section is generally linear. ### Claim 5 (depends on 3) A compressor airfoil tip clearance optimization system of claim 3, wherein the OD flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially upstream section formed from less than 60 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 6 (depends on 3) A compressor airfoil tip clearance optimization system of claim 3, wherein the OD flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 7 (depends on 6) A compressor airfoil tip clearance optimization system of claim 6, wherein the ID flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 8 (depends on 6) A compressor airfoil tip clearance optimization system of claim 6, wherein the at least one clearance reduction system is a hydraulic clearance reduction system. ### Claim 9 A compressor airfoil tip clearance optimization system for increasing efficiency of a turbine engine by reducing the clearance between a tip of a compressor airfoil and a radially adjacent component of the turbine engine, comprising: at least one generally elongated blade having a leading edge, a trailing edge, the tip section at a first end, and a root coupled to the blade at an end generally opposite the first end for supporting the blade and for coupling the blade to a disc of a rotor assembly; at least one generally elongated compressor vane affixed to a stationary component such that the at least one generally elongated compressor vane does not rotate with a rotor assembly during turbine engine operation; an ID flowpath boundary extending from generally an upstream end of a compressor to generally a downstream end of the compressor, wherein the ID flowpath boundary is formed in part from a compressor rotor assembly; an OD flowpath boundary extending from generally the upstream end of the compressor to generally the downstream end of the compressor, wherein the OD flowpath boundary is formed in part from a compressor casing; at least one clearance reduction system configured to move the rotor assembly axially to reduce tip clearance of the at least one generally elongated blade and the at least one generally elongated compressor vane; wherein the ID flowpath boundary increases in distance radially outward from a longitudinal axis when moving axially downstream in a direction from the upstream end to the downstream end; wherein the OD flowpath boundary increases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially downstream section of the OD flowpath boundary formed from less than 40 percent of an axial length of the compressor extending upstream from the downstream end of the compressor; and wherein the ID flowpath boundary increases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially downstream section of the inward flowpath boundary formed from less than 40 percent of an axial length of the compressor extending upstream from the downstream end of the compressor. ### Claim 10 (depends on 9) A compressor airfoil tip clearance optimization system of claim 9, wherein the OD flowpath boundary upstream of the axially downstream section is generally linear. ### Claim 11 (depends on 10) A compressor airfoil tip clearance optimization system of claim 10, wherein the OD flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 12 (depends on 10) A compressor airfoil tip clearance optimization system of claim 10, wherein the ID flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 13 (depends on 9) A compressor airfoil tip clearance optimization system of claim 9, wherein the OD flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially upstream section formed from less than 60 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 14 (depends on 9) A compressor airfoil tip clearance optimization system of claim 9, wherein the at least one clearance reduction system is a hydraulic clearance reduction system. ### Claim 15 A compressor airfoil tip clearance optimization system for increasing efficiency of a turbine engine by reducing the clearance between a tip of a compressor airfoil and a radially adjacent component of the turbine engine, comprising: at least one generally elongated blade having a leading edge, a trailing edge, the tip section at a first end, and a root coupled to the blade at an end generally opposite the first end for supporting the blade and for coupling the blade to a disc of a rotor assembly; at least one generally elongated compressor vane affixed to a stationary component such that the at least one generally elongated compressor vane does not rotate with a rotor assembly during turbine engine operation; an ID flowpath boundary extending from generally an upstream end of a compressor to generally a downstream end of the compressor, wherein the ID flowpath boundary is formed in part from a compressor rotor assembly; an OD flowpath boundary extending from generally the upstream end of the compressor to generally the downstream end of the compressor, wherein the OD flowpath boundary is formed in part from a compressor casing; at least one clearance reduction system configured to move the rotor assembly axially to reduce tip clearance of the at least one generally elongated blade and the at least one generally elongated compressor vane; wherein a midsection of the ID flowpath boundary is generally aligned with a longitudinal axis when moving axially downstream in a direction from the upstream end to the downstream end; wherein the OD flowpath boundary increases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially downstream section of the outward flowpath boundary formed from less than 40 percent of an axial length of the compressor extending upstream from the downstream end of the compressor; wherein the ID flowpath boundary increases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially downstream section of the inward flowpath boundary formed from less than 40 percent of an axial length of the compressor extending upstream from the downstream end of the compressor; wherein the OD flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end to the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor; and wherein the ID flowpath boundary decreases in distance radially outward when moving axially downstream in a direction from the upstream end toward the downstream end in an axially upstream section formed from less than 20 percent of an axial length of the compressor extending downstream from the upstream end of the compressor. ### Claim 16 (depends on 9) A compressor airfoil tip clearance optimization system of claim 9, wherein the OD flowpath boundary upstream of the axially downstream outward section is generally linear. ### Claim 17 (depends on 9) A compressor airfoil tip clearance optimization system of claim 9, wherein the ID flowpath boundary upstream of the axially downstream inward section is generally linear.