# US 12,180,855 B2 · Rotor blade for a turbomachine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,180,855 B2 - Document ID: US12180855B2 - Status: Granted - Kind: B2 - Application number: 17/757,621 - Filed: 2020-12-14 - Published: 2023-01-26 - Granted: 2024-12-31 - Earliest claimed: 2019-12-20 - Assignees: MTU Aero Engines AG - Applicants: MTU Aero Engines AG - Inventors: Karl Maar; Franz Malzacher; Martin Pernleitner - Web page: https://patentgrep.com/patent/US12180855B2 ## CPC - F01D 5/141: {Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147)} - F01D 5/28: Selecting particular materials; {Particular measures relating thereto;} Measures against erosion or corrosion - F05D 2220/323: for aircraft propulsion, e.g. jet engines - 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 2240/301: Cross-sectional characteristics - F05D 2240/303: related to the leading edge of a rotor blade - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - 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 The present invention relates to a rotor blade (20) for arrangement in a gas duct (2) of a turbomachine (1), having a rotor blade airfoil (23), which, viewed in a tangential section, has a blade airfoil profile (24) with a leading edge radius RVK and a rotor blade airfoil thickness d, wherein the blade airfoil profile (24) is thickened, at least in sections, specifically the blade airfoil thickness d is specified, in relation to the front edge radius RVK, such that (2d/Rvk2)−d≤5.5. ## Claims ### Claim 1 A rotor blade for arrangement in a gas duct of a turbomachine, wherein the rotor blade comprises a rotor blade airfoil which, when viewed in a tangential section, has a blade airfoil profile comprising a front edge radius RVK, and a blade airfoil thickness d, the blade airfoil profile being thickened at least in sections, and the blade airfoil thickness d being set with respect to the front edge radius RVK such that at least at a spacing A of 1 mm or 0.5 mm, measured along a skeletal line of the blade airfoil from the front edge thereof, (2×d/RVK2)−d≤5.5 and wherein: i) the blade airfoil thickness d in a front edge region at the spacing A is from 0.5 mm to 5 mm; and/or (ii) in terms of a chord length l measured on the blade airfoil profile, the blade airfoil thickness d is set at a ratio to the front edge radius RVK and the chord length l such that 4.0≤d/(RVK×1)≤7.0; and/or iii) in terms of the chord length 1 measured on the blade airfoil profile, at least at the spacing A between 1.0 mm and 2.0 mm that is measured along the skeletal line of the blade airfoil profile from the front edge thereof, the blade airfoil thickness d is set with respect to the front edge radius RVK and the chord length 1 such that d/(RVK×1)≤7.2; and/or iv) the blade airfoil thickness d is set with respect to the front edge radius RVK such that 0.6≤(2×d/RVK2)−d≤4.0. ### Claim 2 (depends on 1) The rotor blade of claim 1, wherein the front edge radius RVK ranges from 0.2 mm to 1.8 mm. ### Claim 3 (depends on 1) The rotor blade of claim 1, wherein the front edge radius RVK ranges from 0.6 mm to 1.4 mm. ### Claim 4 (depends on 1) The rotor blade of claim 1, wherein the front edge radius RVK ranges from 0.7 mm to 1.4 mm. ### Claim 5 (depends on 1) The rotor blade of claim 1, wherein the blade airfoil thickness d in the front edge region at the spacing A is from 0.5 mm to 5 mm. ### Claim 6 (depends on 1) The rotor blade of claim 1, wherein the blade airfoil thickness d in the front edge region at the spacing A is from 1.5 mm to 4 mm. ### Claim 7 (depends on 1) The rotor blade of claim 1, wherein the blade airfoil thickness d in the front edge region at the spacing A is from 2 mm to 2.5 mm. ### Claim 8 (depends on 1) The rotor blade of claim 1, wherein, in terms of a rotor blade airfoil height H measured from radially inside to radially outside of the rotor blade airfoil, the blade airfoil profile is thickened at radial positions of at least from 60% to 90% of the rotor blade airfoil height H. ### Claim 9 (depends on 1) The rotor blade of claim 1, wherein the blade airfoil thickness d is set at the ratio to the front edge radius RVK and the chord length 1 such that 4.0≤d/(RVK×1)≤7.0. ### Claim 10 (depends on 1) The rotor blade of claim 1, wherein at least at the spacing A between 1.0 mm and 2.0 mm that is measured along the skeletal line of the blade airfoil profile from the front edge thereof, the blade airfoil thickness d is set with respect to the front edge radius RVK and the chord length l such that d/(RVK×1)≤7.2. ### Claim 11 (depends on 1) The rotor blade of claim 1, wherein at least the rotor blade airfoil is made from a brittle material which has a maximum total elongation of less than 6%. ### Claim 12 (depends on 1) The rotor blade of claim 1, wherein at least the rotor blade airfoil is made from a high-temperature-resistant material which is suitable for use in temperatures of up to at least 700° C. ### Claim 13 (depends on 1) The rotor blade of claim 1, wherein the rotor blade airfoil is a solid profile. ### Claim 14 (depends on 1) A turbine module for an aircraft engine, wherein the module comprises the rotor blade of claim 1. ### Claim 15 (depends on 14) An aircraft engine, wherein the aircraft engine comprises the turbine module of claim 14. ### Claim 16 (depends on 1) The rotor blade of claim 1, wherein the blade airfoil thickness d is set with respect to the front edge radius RVK such that 0.6≤(2×d/RVK2)−d≤4.0. ### Claim 17 A rotor blade for arrangement in a gas duct of a turbomachine, wherein the rotor blade comprises a rotor blade airfoil which, when viewed in a tangential section, has a blade airfoil profile comprising a front edge radius RVK, and a blade airfoil thickness d, the blade airfoil profile being thickened at least in sections, and the blade airfoil thickness d being set with respect to the front edge radius RVK such that (2×d/RVK2)−d≤5.5 and wherein, in terms of a chord length l measured on the blade airfoil profile, the blade airfoil thickness d is set with respect to the front edge radius RVK and the chord length 1 such that 4.0≤d/(RVK×1)≤7.2.