Exhaust flow mixers and nozzles
First Claim
Patent Images
1. A turbofan aeroengine comprising:
- a core engine;
a bypass duct surrounding said core engine and having a single propulsion nozzle, a turbine exhaust stream and a bypass fan air stream being mixed internally of said aeroengine to produce a combined exhaust stream for passage through said propulsion nozzle;
said core engine having an exhaust mixing nozzle of the multi-lobed type having a shape in end elevation comprising lobes radiating from a common central area with troughs between said lobes;
said lobes and troughs comprising, respectively, outwardly directed flow channels for said turbine exhaust stream and inwardly directed flow channels for said bypass fan air stream to mix a substantial portion of said turbine exhaust stream and said bypass air stream; and
means including said exhaust mixing nozzle for providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass air stream flowing past said exhaust mixing nozzle, for generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said exhaust mixing nozzle, and for mixing a substantial portion of said turbine exhaust stream and said bypass fan air stream to produce a combined mixed exhaust stream for passage through said propulsion nozzle, said means including;
said exhaust mixing nozzle being formed of a plurality of twisted flow surfaces, said twisted flow surfaces having upstream and downstream ends and having a predetermined and progressive degree of twist between said upstream and said downstream ends,peripherally adjacent ones of said twisted flow surfaces being of mutually complementary and opposite twists to define said outwardly and inwardly directed flow channels of said lobes and said troughs,said peripherally adjacent twisted lobe surfaces being peripherally adjoining at least at their upstream ends and over at least a major portion of said inwardly directed flow channels;
said twisted flow surfaces providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass fan air stream flowing over said flow surfaces to deflect said stream portions without said stream portions breaking away from said flow surfaces and generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said downstream end of each of said flow surfaces, adjacent circumferential ones of said vortices being counter-rotating to promote further mixing, said exhaust mixing nozzle thereby producing a mixing action substantially thoughout said combined exhaust stream before passage of said combined exhaust stream through said propulsion nozzle.
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Abstract
An exhaust mixer of the multi-lobed type for a mixed stream turbofan. In order to promote cortical mixing between the turbine exhaust stream and the fan air stream, the flow surfaces defining the lobes--and the troughs between the lobes--are twisted between their upstream and downstream ends so that opposing sides of each lobe and each trough comprise flow surfaces twisted in opposing senses. Noise suppressing jet propulsion nozzles can be produced with a similar construction.
124 Citations
10 Claims
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1. A turbofan aeroengine comprising:
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a core engine; a bypass duct surrounding said core engine and having a single propulsion nozzle, a turbine exhaust stream and a bypass fan air stream being mixed internally of said aeroengine to produce a combined exhaust stream for passage through said propulsion nozzle; said core engine having an exhaust mixing nozzle of the multi-lobed type having a shape in end elevation comprising lobes radiating from a common central area with troughs between said lobes; said lobes and troughs comprising, respectively, outwardly directed flow channels for said turbine exhaust stream and inwardly directed flow channels for said bypass fan air stream to mix a substantial portion of said turbine exhaust stream and said bypass air stream; and means including said exhaust mixing nozzle for providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass air stream flowing past said exhaust mixing nozzle, for generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said exhaust mixing nozzle, and for mixing a substantial portion of said turbine exhaust stream and said bypass fan air stream to produce a combined mixed exhaust stream for passage through said propulsion nozzle, said means including; said exhaust mixing nozzle being formed of a plurality of twisted flow surfaces, said twisted flow surfaces having upstream and downstream ends and having a predetermined and progressive degree of twist between said upstream and said downstream ends, peripherally adjacent ones of said twisted flow surfaces being of mutually complementary and opposite twists to define said outwardly and inwardly directed flow channels of said lobes and said troughs, said peripherally adjacent twisted lobe surfaces being peripherally adjoining at least at their upstream ends and over at least a major portion of said inwardly directed flow channels; said twisted flow surfaces providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass fan air stream flowing over said flow surfaces to deflect said stream portions without said stream portions breaking away from said flow surfaces and generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said downstream end of each of said flow surfaces, adjacent circumferential ones of said vortices being counter-rotating to promote further mixing, said exhaust mixing nozzle thereby producing a mixing action substantially thoughout said combined exhaust stream before passage of said combined exhaust stream through said propulsion nozzle. - View Dependent Claims (2, 3, 4)
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5. A turbofan aeroengine comprising:
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a core engine; a bypass duct surrounding said core engine and having a single propulsion nozzle, a turbine exhaust stream and a bypass fan air stream being mixed internally of said aeroengine to produce a combined exhaust stream for passage through said propulsion nozzle; said core engine having an exhaust mixing nozzle of the multi-lobed type having a shape in end elevation comprising lobes radiating from a common central area with troughs between said lobes; said lobes and troughs comprising, respectively, outwardly directed flow channels for said turbine exhaust stream and inwardly directed flow channels for said bypass fan air stream to mix a substantial portion of said turbine exhaust stream and said bypass fan air stream; and means including said exhaust mixing nozzle for providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass air stream flowing past said exhaust mixing nozzle, for mixing a substantial portion of said turbine exhaust stream and said bypass fan air stream and for generating a vortex of a mixed turbine exhaust stream and bypass fan air stream downstream of said exhaust mixing nozzle, said means including; said exhaust mixing nozzle being formed of a plurality of twisted flow surfaces, said twisted flow surfaces having upstream and downstream ends and having a predetermined and progressive degree of twist between said upstream and said downstream ends, peripherally adjacent ones of said twisted flow surfaces being of mutually complementary and opposite twists to define said outwardly and inwardly directed flow channels of said lobes and said troughs, said peripherally adjacent twisted lobe surfaces being peripherally contiguous at least at their upstream ends and over at least a major portion of said inwardly directed flow channels; said twisted flow surfaces providing a Coanda Effect to those portions of said turbine exhaust stream and said bypass fan air stream flowing over said flow surfaces to deflect said stream portions without said stream portions breaking away from said flow surfaces and generating a vortex of a mixed turbine exhaust stream and bypass fan air stream downstream of said downstream end of each of said flow surfaces, adjacent circumferential ones of said vortices being counter-rotating to promote further mixing, said exhaust mixing nozzle thereby producing a mixing action substantially thoughout said combined exhaust stream before passage of said combined exhaust stream through said propulsion nozzle. - View Dependent Claims (6, 7, 8)
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9. In a turbonfan aeroengine of the type having a core engine surrounded by a bypass duct and having a single proplusion nozzle, a turbine exhaust stream and a bypass fan air stream being mixed together internally of said aeroengine to produce a combined exhaust stream for passage through said single proplusion nozzle, said core engine having an exhaust mixing nozzle of the multilobed type having a shape in end elevation including lobes radiating from a common central area with troughs between said lobes, said lobes and said troughs comprising, respectively, outwardly directed flow channels for said turbine exhaust stream and inwardly directed flow channels for said bypass fan air stream, the improvement comprising:
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means including said exhaust mixing nozzle for producing a Coanda Effect to those portions of said turbine exhaust stream and said bypass air stream flowing past said exhaust mixing nozzle and for substantially mixing and generating a vortex of said turbine exhaust stream and bypass fan air stream downstream of said exhaust mixing nozzle; said exhaust mixing nozzle having a plurality of twisted flow surfaces, said twisted flow surfaces having upstream and downstream ends and having a predetermined and progressive degree of twist between said upstream ends and said downstream ends; peripherally adjacent ones of said twisted flow surfaces being of mutually complementary and opposite twists to thereby define said outwardly and inwardly directed flow channels of said lobes and said troughs; said peripherally adjacent twisted flow surfaces being peripherally contiguous at least at their upstream ends and over at least a major portion of said inwardly directed flow channels; said twisted flow surfaces providing a Coanda Effect to those portions of said turbine exhaust stream and said fan air stream flowing over said flow surfaces to thereby deflect said stream portions without said stream portions breaking away from said flow surfaces, said Coanda Effect flow generating a vortex of the mixed turbine exhaust stream and fan air stream downstream of said downstream end of each of said flow surfaces, adjacent circumferential ones of said vortices being counter-rotating and promoting further mixing to thereby produce said substantial mixing of said combined exhaust stream before passage thereof through said propulsion nozzle.
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10. A turbofan aeroengine comprising:
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a core engine; a bypass duct surrounding said core engine and having a single propulsion nozzle, a turbine exhaust stream and a bypass fan air stream being mixed internally of said aeroengine to produce a combined exhaust stream for passage through said propulsion nozzle; said core engine having an exhaust mixing nozzle of the multi-lobed type having a shape in end elevation comprising lobes radiating from a common central area with troughs between said lobes; said lobes and troughs comprising, respectively, outwardly directed flow channels for said turbine exhaust stream and inwardly directed flow channels for said bypass fan air stream to mix said turbine exhaust stream and said bypass air stream; and means including said exhaust nozzle for generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said exhaust mixing nozzle to product a combined mixed exhaust stream for passage through said propulsion nozzle, said means including said exhaust mixing nozzle being formed of a plurality of twisted flow surfaces, said twisted flow surfaces having upstream and downstream ends and having a predetermined and progressive degree of twist between said upstream and said downstream ends, peripherally adjacent ones of said twisted flow surfaces being of mutually complementary and opposite twists to define said outwardly and inwardly directed flow channels of said lobes and said troughs, said peripherally adjacent twisted lobe surfaces being peripherally adjoining at least at their upstream ends and over at least a major portion of said inwardly directed flow channels; said twisted flow surfaces generating multiple vortices of a mixed turbine exhaust stream and bypass fan air stream downstream of said downstream end of each of said flow surfaces, adjacent circumferential ones of said vortices being counter-rotating to promote further mixing, said exhaust mixing nozzle thereby producing a mixing action substantially thoughout said combined exhaust stream before passage of said combined exhaust stream through said propulsion nozzle.
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Specification