# US 10,865,809 B1 · Gas turbine engine airfoil frequency design > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,809 B1 - Document ID: US10865809B1 - Status: Granted - Kind: B1 - Application number: 15/869,436 - Filed: 2018-01-12 - Granted: 2020-12-15 - Earliest claimed: 2017-01-17 - Assignees: Raytheon Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Haiyun Li; Eliannah Hunderfund; Sean Nolan - Web page: https://patentgrep.com/patent/US10865809B1 ## CPC - F04D 29/668: {damping or preventing mechanical vibrations} - F01D 5/16: for counteracting blade vibration - F04D 19/02: Multi-stage pumps - F04D 29/023: {especially adapted for elastic fluid pumps} - F04D 29/324: {Blades} - F04D 29/384: {characterised by form} - F04D 29/544: {Blade shapes} - F04D 29/666: {by means of rotor construction or layout, e.g. unequal distribution of blades or vanes} - F02C 3/06: the compressor comprising only axial stages (F02C3/10 takes precedence) - F02K 3/06: with front fan - F05D 2230/80: Repairing, retrofitting or upgrading methods - F05D 2240/30: Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor - F05D 2260/96: Preventing, counteracting or reducing vibration or noise - F05D 2300/175: Superalloys - F05D 2300/501: Elasticity - F05D 2300/522: Density - 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) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A turbomachine airfoil element includes an airfoil having pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges. The airfoil extends in a radial direction a span that is in a range of 0.70-0.85 inch (17.8-20.3 mm). A chord length extends in a chordwise direction from the leading edge to the trailing edge at 50% span and is in a range of 0.85-0.95 inch (21.5-24.0 mm). The airfoil element includes at least two of a first mode with a frequency of 4508±10% Hz, a second mode with a frequency of 7466±10% Hz, a third mode with a frequency of 16104±10% Hz, a fourth mode with a frequency of 18397±10% Hz and a fifth mode with a frequency of 20855±10% Hz. ## Claims ### Claim 1 A turbomachine airfoil element comprising: an airfoil having pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges, the airfoil extending in a radial direction a span that is in a range of 0.70-0.85 inch (17.8-20.3 mm); a chord length extending in a chordwise direction from the leading edge to the trailing edge at 50% span is in a range of 0.85-0.95 inch (21.5-24.0 mm); and at least two of: a first mode has a frequency of 4508 up to ±10% Hz; a second mode has a frequency of 7466 up to ±10% Hz; a third mode has a frequency of 16104 up to ±10% Hz; a fourth mode has a frequency of 18397 up to ±10% Hz; and a fifth mode has a frequency of 20855 up to ±10% Hz; wherein the airfoil is part of an integrally bladed rotor; wherein the first mode is a 1EB mode, the second mode is a 1T mode, the third mode is a 1CWB mode, the fourth mode is a 2B mode, and the fifth mode is a 2T mode, the 1EB and 2EB modes correspond to deflections substantially parallel to thickness direction, the CWB mode corresponds to bending that is substantially normal to the thickness direction, and substantially along the chordwise direction, and the 1T and 2T modes corresponds to twisting about the radial direction. ### Claim 2 (depends on 1) The element of claim 1, wherein three of the first, second, third, fourth, and fifth mode frequencies are present. ### Claim 3 (depends on 1) The element of claim 1, wherein the frequencies are at zero speed and ambient conditions. ### Claim 4 (depends on 3) The element of claim 3, wherein at a running speed/condition: the first mode has a frequency of 4479±10% Hz; the second mode has a frequency of 7142±10% Hz; the third mode has a frequency of 15266±10% Hz; the fourth mode has a frequency of 17621±10% Hz; and the fifth mode has a frequency of 19904±10% Hz. ### Claim 5 (depends on 3) The element of claim 3, wherein the frequencies are within ±5% ranges. ### Claim 6 (depends on 1) The element of claim 1, wherein the airfoil is a nickel-based superalloy. ### Claim 7 (depends on 6) The element of claim 6, the nickel based superalloy has a density of 0.28-0.32 lb/in3 (7.7-8.9 g/cm3). ### Claim 8 (depends on 6) The element of claim 6, the nickel based superalloy has a modulus of elasticity of 27-36 Mpsi (186-248 GPa) at room temperature. ### Claim 9 A method of repairing an airfoil comprising the steps of: providing an airfoil having pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges, the airfoil extending in a radial direction a span that is in a range of 0.70-0.85 inch (17.8-20.3 mm), and a chord length extending in a chordwise direction from the leading edge to the trailing edge at 50% span is in a range of 0.85-0.95 inch (21.5-24.0 mm), wherein the provided airfoil has at least one unrestored mode frequency that is attributable to damage to the airfoil; and repairing the airfoil to provide at least two of: a first mode has a frequency of 4508 up to ±10% Hz; a second mode has a frequency of 7466 up to ±10% Hz; a third mode has a frequency of 16104 up to ±10% Hz; a fourth mode has a frequency of 18397 up to ±10% Hz; and a fifth mode has a frequency of 20855 up to ±10% Hz; wherein the at least one of the first, second, third, fourth and fifth mode frequencies corresponds to a restored mode frequency that supersedes the unrestored mode frequency; wherein the airfoil is part of an integrally bladed rotor; wherein the first mode is a 1EB mode, the second mode is a 1T mode, the third mode is a 1CWB mode, the fourth mode is a 2B mode, and the fifth mode is a 2T mode, the 1EB and 2EB modes correspond to deflections substantially parallel to thickness direction, the CWB mode corresponds to bending that is substantially normal to the thickness direction, and substantially along the chordwise direction, and the 1T and 2T modes corresponds to twisting about the radial direction. ### Claim 10 (depends on 9) The method according to claim 9, wherein the frequencies are at zero speed and ambient conditions, and wherein the airfoil is a nickel-based superalloy. ### Claim 11 A turbofan engine comprising: a fan section; a compressor section arranged fluidly downstream from the fan section; a turbine section arranged fluidly downstream from the compressor section; a combustor arranged fluidly between the compressor and turbine sections; and an airfoil in at least one of the fan, compressor and turbine sections, the airfoil having: pressure and suction sides spaced apart from one another in a thickness direction and joined to one another at leading and trailing edges, the airfoil extending in a radial direction a span that is in a range of 0.70-0.85 inch (17.8-20.3 mm); a chord length extending in a chordwise direction from the leading edge to the trailing edge at 50% span is in a range of 0.85-0.95 inch (21.5-24.0 mm); and at least two of: a first mode has a frequency of 4508 up to ±10% Hz; a second mode has a frequency of 7466 up to ±10% Hz; a third mode has a frequency of 16104 up to ±10% Hz; a fourth mode has a frequency of 18397 up to ±10% Hz; and a fifth mode has a frequency of 20855 up to ±10% Hz; wherein the airfoil is provided in the compressor section, the compressor section includes a low pressure compressor fluidly upstream from a high pressure compressor, and the airfoil is in the high pressure compressor, the airfoil is part of a blade of an integrally bladed rotor; wherein the first mode is a 1EB mode, the second mode is a 1T mode, the third mode is a 1CWB mode, the fourth mode is a 2B mode, and the fifth mode is a 2T mode, the 1EB and 2EB modes correspond to deflections substantially parallel to thickness direction, the CWB mode corresponds to bending that is substantially normal to the thickness direction, and substantially along the chordwise direction, and the 1T and 2T modes corresponds to twisting about the radial direction. ### Claim 12 (depends on 11) The engine of claim 11, wherein the high pressure compressor includes eight stages. ### Claim 13 (depends on 11) The engine of claim 11, wherein is a nickel-based superalloy with a density of 0.28-0.32 lb/in3 (7.7-8.9 g/cm3) and a modulus of elasticity of 27-36 Mpsi (186-248 GPa) at room temperature. ### Claim 14 (depends on 11) The engine of claim 11, wherein three of the first, second, third, fourth, and fifth mode frequencies are present, and wherein the frequencies are at zero speed and ambient conditions.