# US 8,770,920 B2 · Gas turbine airfoil with shaped trailing edge coolant ejection holes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,920 B2 - Document ID: US8770920B2 - Status: Granted - Kind: B2 - Application number: 13/622,055 - Filed: 2012-09-18 - Published: 2013-01-17 - Granted: 2014-07-08 - Earliest claimed: 2010-03-19 - Assignees: ALSTOM Technology Ltd - Applicants: Alstom Technology Ltd - Inventors: Shailendra Naik; Martin Schnieder - Web page: https://patentgrep.com/patent/US8770920B2 ## CPC - F01D 5/187: {Convection cooling} - F05D 2240/122: related to the trailing edge of a stator vane - F05D 2240/304: related to the trailing edge of a rotor blade - 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 ## Abstract A turbine blade or vane includes at least one internal radial channel for the circulation of cooling medium bordered on a pressure side by a pressure side wall and on a suction side by a suction side wall joined at a upstream side at a leading edge and at and downstream side at the trailing edge. At least one exit hole extends through at least one of the pressure side wall or the suction side wall for blowing out of cooling medium from the internal radial channel to a medium surrounding the blade or vane. At least one trailing edge exit hole along the trailing edge has a surfacial exit opening disposed at the pressure side of the trailing edge. ## Claims ### Claim 1 A turbine blade or vane comprising: at least one internal radial channel for the circulation of cooling medium bordered on a pressure side by a pressure side wall and on a suction side by a suction side wall joined at a upstream side at a leading edge and at and downstream side at the trailing edge; at least one exit hole through at least one of the pressure side wall or the suction side wall for blowing out of cooling medium from the internal radial channel to a medium surrounding the blade or vane; at least one trailing edge exit hole along the trailing edge and having a surfacial exit opening disposed at the pressure side of the trailing edge; and at least one radial leading-edge cooling passage disposed in proximity to the leading edge, at least one intermediate cooling passage and at least one trailing edge cooling passage disposed in proximity to the trailing edge, the trailing edge exit hole being supplied by the trailing edge cooling passage; wherein at the trailing edge, the pressure side wall of the blade or vane includes a step recessed towards the suction side, the at least one trailing edge exit hole being at least partly open towards the surrounding medium in a reqion of the step, and wherein the trailing edge exit hole is supplied by cooling medium via a bore which only partly opens in a radially extending leading-edge surface of the step and which at least partly channels through the bottom surface of the step forming scarfed holes. ### Claim 2 (depends on 1) The turbine blade or vane recited in claim 1, wherein the trailing edge exit hole is configured to blow out cooling air to the medium surrounding the blade or vane under an angle with respect to the pressure side wall surface at a blowout point in a range of 5-45°. ### Claim 3 (depends on 1) The turbine blade or vane recited in claim 1, wherein an angle with respect to the pressure side wall surface is in a range of 5-30°. ### Claim 4 (depends on 1) The turbine blade or vane recited in claim 1, wherein the trailing edge side of the surfacial exit opening of the trailing edge exit hole is not more than 50 mm upstream of the trailing edge along the pressure side wall surface. ### Claim 5 (depends on 1) The turbine blade or vane recited in claim 1, wherein at least two trailing edge exit holes are disposed along the trailing edge and along a radial direction that are supplied via individual cooling medium bores connecting the trailing edge exit holes to the internal radial channel. ### Claim 6 (depends on 5) The turbine blade or vane recited in claim 5, wherein at least one of the cooling medium bores or trailing edge exit holes is inclined with respect to an axial direction of a machine with a positive or negative angle in a range of 0-50°. ### Claim 7 (depends on 1) The turbine blade or vane recited in claim 1, wherein the trailing edge exit hole includes a bore connecting the internal radial channel with the medium surrounding the blade or vane, the bore including, on a side connecting to the internal radial channel, a circular cylindrical section, and on a side to the surface of the blade or vane, a widening section conically widening towards the surface of the blade or vane. ### Claim 8 (depends on 7) The turbine blade or vane recited in claim 7, wherein a ratio of a length of the circular cylindrical section to a total length of the circular cylindrical section and the widening section is in the range of 0.2-0.7. ### Claim 9 (depends on 1) The turbine blade or vane recited in claim 1, wherein the trailing edge exit hole includes a bore connecting the internal radial channel with the medium surrounding the blade or vane, a ratio of the length of the bore to a diameter of the bore being in a range of 5-50. ### Claim 10 (depends on 1) The turbine blade or vane recited in claim 1, wherein at least the totality of the surfacial opening of the trailing edge exit hole is located in a radially extending leading-edge surface of the step. ### Claim 11 (depends on 10) The turbine blade or vane recited in claim 10, wherein surfacial opening of the trailing edge exit hole is disposed at an angle in the range of 60-120° with respect to a radially extending bottom surface of the step. ### Claim 12 (depends on 1) The turbine blade or vane recited in claim 1, wherein the trailing edge exit hole is supplied by cooling medium via a bore with a diameter (d) which fully opens in a radially extending leading-edge surface of the step and which is distanced from the bottom surface of the step by a first distance (S1) in a range of S1/d=1.0-1.8, and distanced from the pressure side wall surface by a second distance (S2) in a range of S2/d=0.1-0.3. ### Claim 13 (depends on 5) The turbine blade or vane recited in claim 5, wherein a cross-section of the bore, in one of the wall structure of the blade or vane or at the surfacial opening line, is circular, oval, elliptical or racetrack shaped. ### Claim 14 (depends on 1) The turbine blade or vane recited in claim 1, wherein the blade or vane is at least partly based on metal. ### Claim 15 (depends on 1) The turbine blade or vane recited in claim 1, wherein the blade or vane is a rotating or stationary turbine aerofoil. ### Claim 16 A turbine including a turbine blade comprising: at least one internal radial channel for the circulation of cooling medium bordered on a pressure side by a pressure side wall and on a suction side by a suction side wall joined at a upstream side at a leading edge and at and downstream side at the trailing edge; at least one exit hole through at least one of the pressure side wall or the suction side wall for blowing out of cooling medium from the internal radial channel to a medium surrounding the blade or vane; at least one trailing edge exit hole along the trailing edge and having a surfacial exit opening disposed at the pressure side of the trailing edge; and at least one radial leading-edge cooling passage disposed in proximity to the leading edge, at least one intermediate cooling passage and at least one trailing edge cooling passage disposed in proximity to the trailing edge, the trailing edge exit hole being supplied by the trailing edge cooling passage; wherein at the trailing edge, the pressure side wall of the blade or vane includes a step recessed towards the suction side, the at least one trailing edge exit hole being at least partly open towards the surrounding medium in a region of the step, and wherein the trailing edge exit hole is supplied by cooling medium via a bore which only partly opens in a radially extending leading-edge surface of the step and which at least partly channels through the bottom surface of the step forming scarfed holes. ### Claim 17 (depends on 16) The turbine recited in claim 16, wherein the turbine is a gas turbine.