# US 9,752,589 B2 · Airfoil geometry of blade for axial compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,589 B2 - Document ID: US9752589B2 - Status: Granted - Kind: B2 - Application number: 14/278,048 - Filed: 2014-05-15 - Published: 2014-12-04 - Granted: 2017-09-05 - Earliest claimed: 2013-05-28 - Assignees: Honda Motor Co., Ltd. - Applicants: Honda Motor Co., Ltd. - Inventors: Toyotaka Sonoda; Toshiyuki Arima; Giles Endicott; Markus Olhofer - Web page: https://patentgrep.com/patent/US9752589B2 ## CPC - F04D 29/384: {characterised by form} - F01D 5/141: {Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147)} - F04D 21/00: Pump involving supersonic speed of pumped fluids - F04D 29/324: {Blades} - F04D 29/38: Blades {(for axial flow compressors F04D29/324)} - F04D 29/54: Fluid-guiding means, e.g. diffusers - F04D 29/544: {Blade shapes} - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A suction surface of a blade forming a blade row of an axial compressor includes a concave region having a negative curvature at a leading edge part, and a flat region having substantially zero curvature continued rearwardly of the concave region, so that multiple compression waves are generated, enabling moderation of magnitude of a 1st passage shock to reduce pressure loss and suppress boundary layer separation on the suction surface. Providing a concave region having a negative curvature in a frontal part on a pressure surface of the blade suppresses an increase in the airflow velocity in the frontal part, thus weakening a 2nd passage shock generated on the pressure surface to enable reduction of pressure loss. The concave region of the pressure surface may be extended from a position having a chord length of no greater than 10% to a position having at least 20%. ## Claims ### Claim 1 An airfoil geometry for an axial compressor, in which a blade forming a blade row of the axial compressor includes a leading edge and a trailing edge, and a suction surface and a pressure surface, the suction surface including a suction surface concave region having negative curvature, that is formed in a leading edge part of the suction surface at the leading edge of the blade, and a suction surface flat region having substantially zero curvature, that is continued from the suction surface concave region toward a trailing edge part of the suction surface at the trailing edge of the blade, and the pressure surface including a pressure surface first concave region having negative curvature in a frontal part of the pressure surface in a vicinity of the leading edge of the blade, and the pressure surface further includes a pressure surface second concave region having negative curvature forming a trailing edge part of the pressure surface at the trailing edge of the blade. ### Claim 2 (depends on 1) The airfoil geometry for an axial compressor according to claim 1, wherein at least part of the pressure surface first concave region is present within a range of 10% to 20% of the chord length from the leading edge of the blade toward the trailing edge of the blade. ### Claim 3 (depends on 2) The airfoil geometry for an axial compressor according to claim 2, wherein the pressure surface first concave region is present so as to extend from a position having a chord length of no greater than 10% to a position having a chord length of at least 20% from the leading edge of the blade toward the trailing edge of the blade. ### Claim 4 (depends on 1) The airfoil geometry for an axial compressing according to claim 1, wherein the suction surface of the blade further includes a suction surface convex region having positive curvature that is continued from the suction surface flat region to the trailing edge part of the suction surface at the trailing edge of the blade. ### Claim 5 (depends on 4) The airfoil geometry for an axial compressing according to claim 4, wherein the pressure surface further includes a pressure surface convex region having positive curvature continuing from the pressure surface first concave region toward a trailing edge part of the pressure surface at the trailing edge of the blade. ### Claim 6 (depends on 5) The airfoil geometry for an axial compressing according to claim 5, wherein the pressure surface second concave region continues from the pressure surface convex region. ### Claim 7 (depends on 5) The airfoil geometry for an axial compressing according to claim 5, wherein a center point of the pressure surface is disposed below, in a direction extending from the suction surface to the pressure surface, an imaginary chord line connecting a leading end of the blade at the leading edge of the blade and a trailing end of the blade at the trailing edge of the blade. ### Claim 8 (depends on 1) The airfoil geometry for an axial compressing according to claim 1, wherein the pressure surface further includes a pressure surface convex region having positive curvature continuing from the pressure surface first concave region toward a trailing edge part of the pressure surface at the trailing edge of the blade. ### Claim 9 (depends on 8) The airfoil geometry for an axial compressing according to claim 8, wherein the pressure surface second concave region continues from the pressure surface convex region. ### Claim 10 (depends on 8) The airfoil geometry for an axial compressing according to claim 8, wherein a center point of the pressure surface is disposed below, in a direction extending from the suction surface to the pressure surface, an imaginary chord line connecting a leading end of the blade at the leading edge of the blade and a trailing end of the blade at the trailing edge of the blade. ### Claim 11 (depends on 1) The airfoil geometry for an axial compressing according to claim 1, wherein a center point of the pressure surface is disposed below, in a direction extending from the suction surface to the pressure surface, an imaginary chord line connecting a leading end of the blade at the leading edge of the blade and a trailing end of the blade at the trailing edge of the blade.