# US 2010/0166550 A1 · Methods, systems and/or apparatus relating to frequency-tuned turbine blades > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166550 A1 - Document ID: US20100166550A1 - Status: Published application - Kind: A1 - Application number: 12/347,329 - Filed: 2008-12-31 - Published: 2010-07-01 - Earliest claimed: 2008-12-31 - Inventors: Siddaraja M. Devangada; Ravindra Kumar - Web page: https://patentgrep.com/patent/US20100166550A1 ## CPC - F01D 5/16: for counteracting blade vibration - F01D 5/26: Antivibration means not restricted to blade form or construction or to blade-to-blade connections {or to the use of particular materials} - F01D 9/041: {using blades (F01D5/148 takes precedence)} - Y10T 29/49336: Blade making - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of tuning a compressor stator blade, having a base portion and an airfoil portion, to achieve a desired natural frequency, comprising: a) identifying the natural frequency of the compressor stator blade; b) determining a different target natural frequency for the compressor stator blade; and c) removing material from at least one of the side surfaces of the base portion of the compressor stator blade in an amount and in a configuration that achieves the target natural frequency. ## Claims ### Claim 1 A method of tuning a compressor stator blade, having a base portion and an airfoil portion, to achieve a desired natural frequency, comprising: a) identifying the natural frequency of the compressor stator blade; b) determining a different target natural frequency for the compressor stator blade; and c) removing material from at least one of the side surfaces of the base portion of the compressor stator blade in an amount and in a configuration that achieves the target natural frequency. ### Claim 2 (depends on 1) The method of claim 1, wherein step c) is carried out by forming at least one groove in at least one of the side surfaces of the base portion. ### Claim 3 (depends on 2) The method of claim 2, wherein the groove is a slot with an approximate rectangular cross-section. ### Claim 4 (depends on 1) The method of claim 1, wherein step c) is carried out by forming at least one groove in each of two side surfaces that are substantially parallel to each other. ### Claim 5 (depends on 2) The method of claim 2, wherein: the side surfaces include a pressure side, a suction side, a leading face and a trailing face; the pressure side and suction side are across from and substantially parallel to each other, and the leading face and the trailing face are across from and substantially parallel to each other; and step c) is carried out by forming at least one groove in each of the pressure side and suction side. ### Claim 6 (depends on 2) The method of claim 2, wherein: the side surfaces include a pressure side, a suction side, a leading face and a trailing face; the pressure side and suction side are across from and substantially parallel to each other, and the leading face and the trailing face are across from and substantially parallel to each other; and step c) is carried out by forming at least one groove in each of the trailing face and leading face. ### Claim 7 (depends on 2) The method of claim 2, wherein: the side surfaces include a pressure side, a suction side, a leading face and a trailing face; the pressure side and suction side are across from and substantially parallel to each other, and the leading face and the trailing face are across from and substantially parallel to each other; and step c) is carried out by forming at least one groove in each of the pressure side, the suction side, the trailing face and leading face. ### Claim 8 (depends on 4) The method of claim 4 wherein said groove has substantially parallel sides and a substantially flat base. ### Claim 9 (depends on 4) The method of claim 4 wherein each of said grooves has a constant depth. ### Claim 10 (depends on 4) The method of claim 4 wherein each of said grooves has a constant width. ### Claim 11 (depends on 4) The method of claim 4 wherein each of said grooves has a constant depth and a constant width. ### Claim 12 (depends on 4) The method of claim 4 wherein each of said grooves extends fully across the length of each of the side surfaces. ### Claim 13 (depends on 4) The method of claim 4 wherein said base portion is substantially rectangular, with a pair of relatively longer side surfaces, a pair of relatively shorter end surfaces, a radially inner surface and a radially outer surface. ### Claim 14 (depends on 4) The method of claim 4, wherein the cross-sectional profile of the groove is one of rectangular, semi-circular, semi-oval shape, conical shape with a rounded end, rectangular shape that terminates into a semi-circular shape, and a rectangular shape that has corner fillets. ### Claim 15 (depends on 2) The method of claim 2, wherein: the base portion includes one or more rails; and step c) is carried out by also removing material from at least one of the rails so to form a tapering rail. ### Claim 16 A compressor stator blade that includes an airfoil portion and a base portion that is substantially rectangular with side surfaces that include a pressure side, a suction side, a leading face and a trailing face, and a radially inner surface and a radially outer surface, the compressor stator blade comprising at least one groove formed in at least one the side surfaces that is configured such that the compressor stator blade has a desired natural frequency. ### Claim 17 (depends on 16) The compressor stator blade according to claim 16, wherein compressor stator blade comprises at least one groove formed in the pressure side and the suction side. ### Claim 18 (depends on 16) The compressor stator blade according to claim 16, wherein compressor stator blade comprises at least one groove formed in the leading face and the trailing face. ### Claim 19 (depends on 16) The compressor stator blade according to claim 16, wherein: the pressure side and suction side are across from and substantially parallel to each other, and the leading face and the trailing face are across from and substantially parallel to each other; and the groove has a substantially constant depth, a substantially constant width, and extends fully across the width of the base portion. ### Claim 20 (depends on 16) The compressor stator blade according to claim 16, wherein the cross-sectional profile of the groove is one of rectangular, semi-circular, semi-oval shape, conical shape with a rounded end, rectangular shape that terminates into a semi-circular shape, and a rectangular shape that has corner fillets.