Localized arc filament plasma actuators for noise mitigation and mixing enhancement
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02K-001/46
F01D-025/30
출원번호
UP-0020019
(2008-01-25)
등록번호
US-7669404
(2010-04-21)
발명자
/ 주소
Samimy, Mohammad
Adamovich, Igor
출원인 / 주소
The Ohio State University
대리인 / 주소
Dinsmore & Shohl LLP
인용정보
피인용 횟수 :
4인용 특허 :
9
초록▼
A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized h
A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.
대표청구항▼
We claim: 1. A method of using an arc filament plasma discharge to control a flow of exhaust gas, said method comprising: flowing fluid through an exhaust duct such that exhaust jet instability frequencies corresponding to said flow are formed thereby; operating an arc generator to form an arc fila
We claim: 1. A method of using an arc filament plasma discharge to control a flow of exhaust gas, said method comprising: flowing fluid through an exhaust duct such that exhaust jet instability frequencies corresponding to said flow are formed thereby; operating an arc generator to form an arc filament plasma that produces a localized perturbation in a portion of said exhaust gas at a frequency that falls within a frequency range of said exhaust jet instability frequencies, said arc generator comprising: an electric current source; and a plurality of electrodes coupled to said electric current source and adjacent a trailing edge of said exhaust duct such that said electrodes do not substantially protrude into said portion of said exhaust gas; and arranging said electrodes such that said localized perturbation generates streamwise vorticity in said portion of said exhaust gas. 2. The method of claim 1, further comprising arranging said electrodes in said exhaust duct to define a substantially flush fit with the surface thereof. 3. The method of claim 1, further comprising operating said arc filament plasma discharge in the presence of a Reynolds Numbers associated with said exhaust gas that exceeds one million. 4. The method of claim 1, further comprising arranging said electrodes around a substantial periphery of said exhaust duct. 5. The method of claim 1, further comprising operating said arc generator to energize said electrodes according to a predetermined frequency and sequence in order to excite at least one flow instability in said exhaust duct. 6. The method of claim 1, further comprising operating said electric current source at alternating current frequencies of up to hundreds of thousand Hertz. 7. The method of claim 1, further comprising operating said electric current source at voltages of up to tens of thousand volts. 8. The method of claim 1, wherein said localized flow perturbations are produced by heating at least a portion of said exhaust duct with said arc filament plasma discharge to effect concomitant pressure increases therein. 9. The method of claim 1, further comprising reducing noise emanating from said exhaust duct through the excitation of jet instabilities therein by generating said arc filament plasma with a predetermined forcing frequency or frequencies within the exhaust jet instability frequency range. 10. The method of claim 1, further comprising operating said arc generator to energize said electrodes according to a predetermined sequence in order to introduce both a streamwise vorticity and excite a flow instability in said flowpath. 11. The method of claim 1, wherein said exhaust duct is substantially axisymmetric. 12. The method of claim 1, wherein said exhaust duct is substantially non-axisymmetric. 13. The method of claim 1, wherein said electrodes are arranged in groups such that each said group defines an actuator. 14. The method of claim 13, further comprising operating all of said actuators at the same time to produce an axisymmetric mode. 15. The method of claim 13, wherein a plurality of said electrodes are electrically coupled to a common ground electrode. 16. The method of claim 13, wherein each said group comprises a pair of electrodes. 17. The method of claim 13, further comprising operating said actuators sequentially to produce a non-axisymmetric mode. 18. The method of claim 1, further comprising enhancing mixing of said exhaust gas with an ambient air stream through the excitation of jet instabilities within said exhaust duct. 19. The method of claim 1, wherein said flowing fluid through an exhaust duct comprises flowing a fluid through each of a core exhaust duct with at least one of said arc generator disposed therein, and a bypass exhaust duct disposed concentrically around said core exhaust duct, said bypass exhaust duct with at least another of said arc generator disposed therein, each of said one and another arc generators configured to selectively operate to produce said localized perturbation within a respective one of said ducts. 20. A method of using an arc filament plasma discharge to control the flow of exhaust gas in an aircraft propulsion system exhaust duct, said method comprising: generating an exhaust gas flow through the operation of an aircraft propulsion system, said exhaust gas flow proceeding in such a way that exhaust jet instability frequencies corresponding to said exhaust gas flow are formed thereby; operating an arc generator to form an arc filament plasma that produces a localized perturbation in a portion of said exhaust gas flow at a frequency that falls within a frequency range of said exhaust jet instability frequencies, said arc generator comprising a plurality of electrodes cooperative with an electric current source and adjacent a trailing edge of said exhaust duct such that said electrodes do not substantially protrude into said portion of said exhaust gas flow; and arranging said electrodes such that said localized perturbation generates streamwise vorticity in said portion of said exhaust gas flow. 21. The method of claim 20, wherein controlling the flow of exhaust gas in an aircraft propulsion system exhaust duct comprises enhancing mixing of said exhaust gas flow with an ambient air stream through the excitation of jet instabilities within said exhaust duct. 22. A method of reducing exhaust noise in an aircraft propulsion system, said method comprising: flowing a fluid along an exhaust duct of said propulsion system such that a flowpath is defined therein, said flowing fluid proceeding in such a way that exhaust jet instability frequencies corresponding to said flowing fluid are formed thereby; and operating an arc generator such that during the flow of said fluid, an arc filament plasma is formed that produces a localized perturbation and attendant streamwise vorticity in said flowing fluid as said flowing fluid passes by electrodes placed adjacent a trailing edge of said exhaust duct in such a way as to not substantially protrude into flowpath, said localized perturbations being produced at a frequency that falls within a frequency range of said exhaust jet instability frequencies such that noise produced by said flowing fluid is reduced. 23. A method of enhancing mixing of exhaust fluids in an aircraft propulsion system with ambient air, said method comprising: flowing a fluid along an exhaust duct of said propulsion system such that a flowpath is defined therein, said flowing fluid proceeding in such a way that exhaust jet instability frequencies corresponding to said flowing fluid are formed thereby; and operating an arc generator such that during the flow of said fluid, an arc filament plasma is formed that produces a localized perturbation and attendant streamwise vorticity in said flowing fluid as said flowing fluid passes by electrodes placed adjacent a trailing edge of said exhaust duct in such a way as to not substantially protrude into flowpath, said localized perturbations being produced at a frequency that falls within a frequency range of said exhaust jet instability frequencies such that mixing of said flowing fluid with the ambient air is enhanced.
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이 특허에 인용된 특허 (9)
Friedrich Thomas E. (7 Egerton Place London ; S.W.3 GBX), Arrangement for suppressing jet engine noise.
Roth John R. (Knoxville TN) Tsai Peter P. (Knoxville TN) Liu Chaoyu (Knoxville TN) Laroussi Mounir (Knoxville TN) Spence Paul D. (Knoxville TN), One atmosphere, uniform glow discharge plasma.
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