# US 12,193,198 B2 · Propulsion system comprising a heat exchanger > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,193,198 B2 - Document ID: US12193198B2 - Status: Granted - Kind: B2 - Application number: 18/512,190 - Filed: 2023-11-17 - Published: 2024-06-13 - Granted: 2025-01-07 - Earliest claimed: 2022-12-09 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Daniel J Sellars; Alec R Groom - Web page: https://patentgrep.com/patent/US12193198B2 ## CPC - F02C 7/14: of fluids in the plant {, e.g. lubricant or fuel (F02C7/185 takes precedence)} - H05K 7/20845: {for automotive electronic casings (H05K7/2089 takes precedence)} - F01D 25/12: Cooling - F28D 7/16: the conduits being arranged in parallel spaced relation ({F28D7/0008 - F28D7/0058 take precedence}; F28D7/02 - F28D7/10 take precedence) - F05D 2260/20: Heat transfer, e.g. cooling - F05D 2260/213: by the provision of a heat exchanger within the cooling circuit - F05D 2260/22141: using fins or ribs - F28D 2021/0021: {for aircrafts or cosmonautics} - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - 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) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general) - 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 propulsion system having an axial direction relating to a principal direction of propulsion, and a height direction perpendicular to the axial direction. The propulsion system includes a duct configured to convey a flow of fluid along the axial direction, and a heat exchanger disposed within the duct. The heat exchanger is defined between an inlet face and an outlet face and is configured to convey the flow of fluid from the inlet face to the outlet face. A heat exchanger length is defined as a minimum distance between the inlet face and the outlet face and wherein the heat exchanger length varies along the height direction such that a resistance to the flow of fluid through the heat exchanger varies along the height direction. ## Claims ### Claim 1 A propulsion system having an axial direction relating to a principal direction of propulsion, and a height direction perpendicular to the axial direction, the propulsion system comprising: a duct configured to convey a flow of fluid along the axial direction; and a heat exchanger disposed within the duct, wherein the heat exchanger is defined between an inlet face and an outlet face and is configured to convey the flow of fluid from the inlet face to the outlet face; wherein a heat exchanger length is defined as a minimum distance between the inlet face and the outlet face, and wherein the heat exchanger length varies along the height direction such that a resistance to the flow of fluid through the heat exchanger varies along the height direction, wherein the duct comprises a top wall and a bottom wall, spaced apart along the height direction, with the heat exchanger extending from the top wall to the bottom wall, wherein the inlet face and the outlet face extend linearly at an angle relative to the axial direction from the top wall to the bottom wall of the duct, wherein the inlet face of the heat exchanger is further upstream within the duct at the bottom wall than at the top wall, and wherein the heat exchanger length varies along the height direction, with the heat exchanger length being smaller at the bottom wall than at the top wall. ### Claim 2 (depends on 1) The propulsion system of claim 1, wherein a normal to an inlet plane which is tangential to the inlet face has a component in the height direction. ### Claim 3 (depends on 1) The propulsion system of claim 1, wherein a normal to an outlet plane which is tangential to the outlet face has a component in the height direction. ### Claim 4 (depends on 2) The propulsion system of claim 2, wherein an axial position of the inlet face varies along the height direction; wherein the heat exchanger length varies along the height direction, in correspondence to the axial position of the inlet face. ### Claim 5 (depends on 1) The propulsion system of claim 1, wherein the heat exchanger comprises a plurality of fins radially offset from one another and extending with a component in the axial direction. ### Claim 6 (depends on 5) The propulsion system of claim 5, wherein a fin density is defined as a minimum distance between adjacent fins, and the fin density varies along the height direction. ### Claim 7 (depends on 4) The propulsion system of claim 4, wherein the heat exchanger comprises a plurality of fins radially offset from one another and extending with a component in the axial direction, a fin density is defined as a minimum distance between adjacent fins, the fin density varies along the height direction, and the fin density continually increases along the height direction from the bottom wall to the top wall of the duct. ### Claim 8 (depends on 1) The propulsion system of claim 1, wherein the propulsion system is a gas turbine engine. ### Claim 9 (depends on 8) The propulsion system of claim 8, wherein an inlet of the duct is configured to receive a flow of air from a bypass duct of the gas turbine engine, and wherein the duct is configured to convey the flow of air from the inlet to an outlet, through the heat exchanger. ### Claim 10 (depends on 1) The propulsion system of claim 1, wherein the propulsion system includes an electric motor. ### Claim 11 (depends on 1) An aircraft comprising the propulsion system of claim 1.