US3695388A - Quiet jet discharge nozzle - Google Patents

Quiet jet discharge nozzle Download PDF

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Publication number
US3695388A
US3695388A US152696A US3695388DA US3695388A US 3695388 A US3695388 A US 3695388A US 152696 A US152696 A US 152696A US 3695388D A US3695388D A US 3695388DA US 3695388 A US3695388 A US 3695388A
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US
United States
Prior art keywords
nozzle
orifices
trailing edge
set forth
orifice
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US152696A
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English (en)
Inventor
Vincent B Paxhia
Franklin B Bossler
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Textron Inc
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Textron Inc
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Publication date
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/40—Nozzles having means for dividing the jet into a plurality of partial jets or having an elongated cross-section outlet

Definitions

  • ABSTRACT An improved air/gas jet nozzle of multiple orifice form is disclosed, the output of which is substantially inaudible to the human ear.
  • the nozzle comprises an airfoil-shaped plenum having discharge orifices in its trailing edge. Sheaths of inaudible range vibrating air are induced to surround the discharge streams from the nozzle orifices and mask the audible range sound therein.
  • the invention contemplates a multiple-orifice nozzle embodying novel orifice positional relationships and jet stream velocities which are as high as possible without'being supersonic; the nozzle orifices being small as possible without producing excessive thrust losses due to viscosity effects.
  • FIG. 1 is a side elevational view of one form of multiple orifice nozzle of the present invention
  • FIG. 2 is a rear end view thereof
  • FIG. 3 is a fragmentary sectional view thereof, on enlarged scale, taken as suggested by line 33 of FIG. 1 and illustrating operation of the invention
  • FIG. 4 is a rear elevational view of another form of thereof have been attenuated into inaudible levels.
  • a single jet blast or jet stream would be sheathed by an envelope of ambient air flowing alongside-360 of the periphery of the jet stream; but only within other specific parameters as explained hereinafter.
  • the nozzle plenum may be constructed as shown in the accompanying drawing, and as shown therein a preferred form of the nozzle of the invention is provided to comprise a hollow shell 10 which is elongated in at least two directions so as to provide a plenum for supplying and accommodating a plurality of jet stream discharge orifices 12.
  • the shell 10 is externally airfoil-shaped as illustrated at FIG. 3, and is mounted in flow communication with any preferred form of pressured fluid supply conduit such as illustrated at 14.
  • the rear edge portion of the shell 10 is ogive-shaped and terminates in a trailing edge 18.
  • the orifices 12 may be arranged in a single vertical row, exiting directly through the trailing edge portion 18 of the nozzle.
  • a plurality of orifices 12 are relatively positioned and arrayed so as to be staggered alternatively in parallel rows at opposite sides of the trailing edge 18, and are canted in their directions of discharge as best shown at FIG. 5. In any case it will be apparent from examination of FIGS.
  • each ultra-sonic jet stream 22 issuing from an orifice 12 will induce flow therearound of an external shell of sound-masking subsonic ambient air 20 about the entire 360 of its sectional periphery; the orifices 12 being so relatively spaced that the induced air flow streams avoid interference with each other.
  • FIG. 3 herewith illustrates this feature of the invention; and it is by reason of this arrangement that maximum noise supression is obtained.
  • Various patterns of multiple port arrangements have been tested with this object in mind, whereupon it was discovered that when working relative to the median camber line of the shell 10, so as to relatively diverge approximately 4.
  • the jet stream discharge orifices are drilled through the trailing edge wall section of the nozzle asshown; and it has been determined that the orifice diameters should be such that air will be discharged therethrough at a rate less than Mach 1, and preferably between Mach .6 and .8 or thereabove, approaching but never reaching Mach 1.
  • Such results are attained for example by furnishing air/gas to orifices of about 0.040 inches diameters at pressures up to about psi.
  • the orifice exits should then be relatively spaced apart within the range of 1.5 to 4.3 times the orifice diameters.
  • a preferred positional arrangement for an array of orifices as shown in FIGS. 2, 4,6, herewith would locate the orifices on centers approximately two orifice diameters apart in all directions.
  • Nozzle efficiency is defined as the ratio of the actual thrust obtained to the thrust that could be theoretically obtained by isentropic expansion for the same mass flow rate and pressure ratio. This distinction is very important. In practice, duct and nozzle losses may be lar.- gely offset by providing slightly larger nozzle areas, to restore the mass flow rate to the ideal flow. The loss of thrust is then proportional to the square root of the pressure loss instead of being directionally proportional to it.
  • the sound pressure from the jet orifices should be predominately at frequencies at the upper range of audibility and beyond.
  • the influence of nozzle-exit diameters and relative spacings apart as well as nozzle-exit velocities are critical. For example, it has been determined that .04 inch diameter jet bores provide relatively low power spectral densities when operating at efficient pressure ratios. Although smaller jet bores provide a,lower,overall noise level eir fabrica ion and operative maintenance 18 more I icult. There ore, the
  • An inaudible thrust producing discharge nozzle device comprising an externally airfoil-shaped plenum having a trailing edge and air discharge orifice means extending through the wall portion of said trailing edge,
  • said orifice means including a row of separate orifices of circular section directing discharge of high speed air jet streams from said plenum rearwardly of said trailing edge and being relatively spaced apart so as to induce flows of air from the ambient atmosphere encasing each high speed dis-charge jet stream within a non-turbulent sheath of inaudible range vibrating air, thereby masking the audible range sound propogations of said jet streams until they are attenuated and reduced to inaudible levels.
  • a nozzle as set forth in claim 1 wherein said orifice means comprises two rows of orifices exiting at opposite sides of said trailing edge at staggered spaced apart positions symmetrically thereof.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Nozzles (AREA)
US152696A 1971-06-14 1971-06-14 Quiet jet discharge nozzle Expired - Lifetime US3695388A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15269671A 1971-06-14 1971-06-14

Publications (1)

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US3695388A true US3695388A (en) 1972-10-03

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US152696A Expired - Lifetime US3695388A (en) 1971-06-14 1971-06-14 Quiet jet discharge nozzle

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US (1) US3695388A (https=)
CA (1) CA953755A (https=)
FR (1) FR2141913B1 (https=)
GB (1) GB1378943A (https=)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4090583A (en) * 1976-02-02 1978-05-23 Leonard James L Streamlined monolithic internal combustion engine muffler
US4966338A (en) * 1987-08-05 1990-10-30 General Electric Company Aircraft pylon
US5156353A (en) * 1987-04-13 1992-10-20 General Electric Company Aircraft pylon
US5929396A (en) * 1997-07-29 1999-07-27 Awad; Elias A. Noise reducing diffuser
US20070029132A1 (en) * 2005-08-05 2007-02-08 Feight Robert P Ported aerodynamic exhaust tailpipe
US20090013675A1 (en) * 2007-07-13 2009-01-15 Paccar Inc Flow diffuser for exhaust pipe
US20090014235A1 (en) * 2007-07-13 2009-01-15 Paccar Inc Flow diffuser for exhaust pipe
US20130251876A1 (en) * 2011-02-18 2013-09-26 Sanyo Foods Co., Ltd. Process for producing instant noodles

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB514913A (en) * 1937-05-24 1939-11-21 Bronzavia Sa Improvements in or relating to the exhaust pipes of internal combustion engines
FR859272A (fr) * 1939-04-26 1940-12-14 Apyr Perfectionnements apportés aux collecteurs tuyaux et pipes d'échappement pour moteurs d'avions à refroidissement par air ou par liquides
US2845775A (en) * 1956-06-01 1958-08-05 United Aircraft Corp Noise suppressors for jet engines

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB514913A (en) * 1937-05-24 1939-11-21 Bronzavia Sa Improvements in or relating to the exhaust pipes of internal combustion engines
FR859272A (fr) * 1939-04-26 1940-12-14 Apyr Perfectionnements apportés aux collecteurs tuyaux et pipes d'échappement pour moteurs d'avions à refroidissement par air ou par liquides
US2845775A (en) * 1956-06-01 1958-08-05 United Aircraft Corp Noise suppressors for jet engines

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4090583A (en) * 1976-02-02 1978-05-23 Leonard James L Streamlined monolithic internal combustion engine muffler
US5156353A (en) * 1987-04-13 1992-10-20 General Electric Company Aircraft pylon
US4966338A (en) * 1987-08-05 1990-10-30 General Electric Company Aircraft pylon
US5929396A (en) * 1997-07-29 1999-07-27 Awad; Elias A. Noise reducing diffuser
US20070029132A1 (en) * 2005-08-05 2007-02-08 Feight Robert P Ported aerodynamic exhaust tailpipe
US7703573B2 (en) * 2005-08-05 2010-04-27 Paccar Inc Ported aerodynamic exhaust tailpipe
AU2006203280B2 (en) * 2005-08-05 2011-04-28 Paccar Inc Ported aerodynamic exhaust tailpipe
US20090013675A1 (en) * 2007-07-13 2009-01-15 Paccar Inc Flow diffuser for exhaust pipe
US20090014235A1 (en) * 2007-07-13 2009-01-15 Paccar Inc Flow diffuser for exhaust pipe
US7971432B2 (en) 2007-07-13 2011-07-05 Paccar Inc Flow diffuser for exhaust pipe
US20130251876A1 (en) * 2011-02-18 2013-09-26 Sanyo Foods Co., Ltd. Process for producing instant noodles
US10925301B2 (en) * 2011-02-18 2021-02-23 Sanyo Foods Co., Ltd. Process for producing instant noodles

Also Published As

Publication number Publication date
FR2141913A1 (https=) 1973-01-26
FR2141913B1 (https=) 1977-12-23
CA953755A (en) 1974-08-27
GB1378943A (en) 1975-01-02

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