EP0414863B1 - Überschalldüse mit reduziertem geräusch - Google Patents

Überschalldüse mit reduziertem geräusch Download PDF

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Publication number
EP0414863B1
EP0414863B1 EP90904011A EP90904011A EP0414863B1 EP 0414863 B1 EP0414863 B1 EP 0414863B1 EP 90904011 A EP90904011 A EP 90904011A EP 90904011 A EP90904011 A EP 90904011A EP 0414863 B1 EP0414863 B1 EP 0414863B1
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EP
European Patent Office
Prior art keywords
nozzle
supersonic
exit
passageway
flow
Prior art date
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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EP90904011A
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English (en)
French (fr)
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EP0414863A1 (de
Inventor
Daniel L. Lloyd
Richard J. Madlener
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Cold Jet LLC
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Cold Jet LLC
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C5/00—Devices or accessories for generating abrasive blasts
    • B24C5/02—Blast guns, e.g. for generating high velocity abrasive fluid jets for cutting materials
    • B24C5/04—Nozzles therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/002—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to reduce the generation or the transmission of noise or to produce a particular sound; associated with noise monitoring means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/003—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods using material which dissolves or changes phase after the treatment, e.g. ice, CO2

Definitions

  • the present invention relates generally to supersonic nozzles and is particularly directed to attenuating the noise emitted by supersonic nozzles during operation.
  • the invention will be specifically disclosed in connection with a supersonic nozzle having an exit to throat ratio within a specified range, internal features of the supersonic passageway, and external configurations of the nozzle body which tend to reduce the noise emitted therefrom.
  • Supersonic nozzles are well known in the art.
  • Conventional converging-diverging nozzles include a converging section, a throat, and a diverging section. If sufficient pressure is applied to a converging-diverging nozzle, air velocity of the throat will become sonic, and then increase as the air expands at the diverging section to produce a supersonic outlet velocity. The exact exit velocity depends on air pressure, size, and other details of the nozzle design.
  • a nozzle of this type is disclosed in U.S. Patent No. 4184638.
  • Nozzles may be used for a variety of purposes. They may be operated automatically while located a distance from the operator and other people. Other nozzles may be hand held by an operator who directs the exiting flow in order to achieve a particular purpose. One specific use of such nozzles is in combination with a particle blast cleaning apparatus such as that disclosed in U.S. Patent No. 4,744,181. Such nozzles are typically of the type hand held by an operator, who directs the flow, which is a mixture of transport gas flowing at a supersonic velocity and carbon dioxide pellets carried along by the transport gas. The flow is directed onto an object to be cleaned by particle blast or cryogenic particle blast cleaning methods.
  • a major problem with the use of supersonic nozzles is the decibel level of the noise emitted by the nozzle during operation. Such noise becomes a critical factor in the acceptability and use of a particular nozzle design when people are required to be nearby. Furthermore, when such nozzles are used in an enclosed area, such as a factory, the reflective surfaces of the area can tend to increase the decibel level experienced at particular locations.
  • a sound pressure level of 120 dB on the A scale has been determined by OSHA to be the threshold level of pain for a human being.
  • OSHA limits the exposure level of a person to such noises to less than 90 dBA for an eight hour time period. Industry and military standards establish this level at 85 dBA.
  • Typical prior art nozzles as used for particle blast cleaning apparatuses, have been measured to emit noise as high as 130 dBA at the operator's position.
  • the nozzle disclosed by U.S. Patent No. 4,038,786 has been documented to emit noise in the range of 127 dBA. Since the dB scale is logarithymic, a change of three decibels represents a doubling of the sound pressure level.
  • the difference between the OSHA 120 dBA threshold level of pain and the 127 dBA of the typical prior art nozzle represents over a fourfold increase in the sound pressure level. When compared to the 90 dBA OSHA limit, this difference is an increase of over 4,000 times the sound pressure level of 90 dBA.
  • the 127 dBA level of the typical prior art nozzle has a sound pressure level more than 16,000 times this standard.
  • the sound emitted by supersonic nozzles must be reduced to as low a level as possible to permit safe continuous operation. While ear protection is available, such protective devices attenuate the noise only in the range of 20 to 25 dBA. This would result in a sound pressure level of the typical 127 dBA prior art nozzle of as low as a 102 dBA at the operator's position. While this would drastically reduce the sound pressure level experienced by the operator, it would still remain above the OSHA, industry, and military limits for eight hours of exposure. Furthermore, in a factory situation, it is unrealistic to require workers in nearby areas who are not involved with the supersonic nozzle use to wear such ear protection.
  • the ultimate goal and solution is to use a supersonic nozzle which has a sound pressure level low enough that an operator wearing approved ear protection devices is subjected to less than 85 dBA.
  • a nozzle would have to have a sound pressure level of less than 115 dBA at the operator position.
  • the 115 dBA level would also be acceptable to workers without ear protection devices who are more than 15 feet from the operating nozzle.
  • Yet another object of the present invention is to provide a supersonic nozzle which may be used in the presence of nearby workers who do not have to wear ear protection devices to meet the OSHA, industry, and military standards for sound pressure level exposure.
  • an improved supersonic nozzle which has a passageway formed in a nozzle body which has an inlet, a throat, and an exit.
  • the exit area to throat area ratio is in the range of 2.5 to 6.0 whereby the static pressure of the supersonic flow at the exit is less than the static ambient pressure.
  • a sound attenuating supersonic nozzle connectable to a flow of compressible fluid comprising:
  • said cavities are formed longitudinally in said exterior surface.
  • a plurality of inserts may be provided, having complimentary shapes to said longitudinal cavities, said inserts being disposed in said cavities.
  • a sound attenuating supersonic nozzle connectable to a flow of compressible fluid comprising:
  • said exit opening is at least 25% larger than said exit of said supersonic passageway.
  • the nozzle may also comprise first means for allowing auxiliary air flow into said exit cavity, said first means including means for allowing said auxiliary air flow to exit through said exit opening of said shield.
  • said first means comprises a gill cavity formed between said exterior surface and said shield, said gill cavity communicating with the ambient environment at one end and with said exit cavity at the other end.
  • said exit opening has a perimeter and further comprises a gill angle formed between said exterior surface and said perimeter, said gill angle being at least 60°.
  • the shield may so be constructed as not directly to contact any portion of said exterior surface.
  • spacers are disposed between said shield and said exterior surface of said nozzle body.
  • a sound attenuating supersonic nozzle connectable to a flow of compressible fluid comprising:
  • said longitudinal grooves extend from said exit inwardly toward said throat to the point in said diverging section at which the static pressure of the supersonic flow during operation of said nozzle is equal to the static ambient pressure.
  • the depth of said grooves is preferably in the range of 127 ⁇ m to 381 ⁇ m, and the distance between said grooves is preferably in the range of 762 ⁇ m to 1270 ⁇ m.
  • the supersonic passageway has an elongated rectangular cross sectional shape formed by two sets of opposing surfaces, said longitudinal grooves being formed in one set of said opposing surfaces.
  • figure 1 shows a supersonic nozzle generally designated by the numeral 1 constructed in accordance with the present invention.
  • Nozzle body 2 is shown as being formed of an upper section 3 and a lower section 4, held together by a plurality of fasteners, such as bolts 5.
  • the supersonic passageway 6 is formed symmetrically in upper section 3 and lower section 4, and is shown as a profile, having an inlet 7, a throat 8, and an exit 9.
  • nozzle inlet 10 is shown connected to nozzle body 2 by bolts 11.
  • a passageway (not shown) is formed through the interior of nozzle inlet 10 which communicates with inlet 7 at one end, and is connectable to receive a flow of compressible fluid at the other end 12.
  • a pair of spaced grooves 13, 14 are formed about the circumference of nozzle inlet 10 near end 12.
  • FIG 2 which is an end view of nozzle 1, the exterior surface 15 of nozzle body 2 can be seen as being continuous in nature.
  • Passageway 6 and exit 9 are shown as having an elongate rectangular cross sectional shape.
  • an elongate rectangle has a dimension in one direction which is substantially larger than the dimension in the other direction.
  • the rectangle is formed by an interior wall 16 of supersonic passageway 6. While supersonic passageway 6 is shown as an elongate rectangle in cross section, as will be described later, it may also be circular in cross section.
  • an elongate rectangle or a circle, supersonic passageway 6 is considered to have one interior wall 16, although as shown in figure 2 with the elongate rectangular cross sectional shape, there are four distinct surfaces, 16A, 16B, 16C, and 16D.
  • the rectangular cross section can be considered to be constructed of two sets of opposing surfaces 16A-16C, and 16B-16D.
  • grooves 17 are shown adjacent exit 9 in figure 3, as actually starting at exit 9. In practice, grooves 17 may actually extend from exit 9, or be formed a short distance upstream of exit 9. Grooves 17 extend inwardly from exit 9 toward throat 8 along a length of supersonic passageway 6, to point 18. As shown, grooves 17 are formed as a series of recesses 17A and ridges 17B, along interior walls 16B and 16D.
  • supersonic passageway 6 is shown having a converging section 19 from inlet 7 to throat 8.
  • a diverging section 19A is shown from throat 8 to exit 9.
  • Figure 4 shows a cross section taken through throat 8, showing the rectangular shape thereof, and also indicating that throat 8 has the smallest cross sectional area of any location in supersonic passageway 6.
  • end 12 of nozzle inlet 10 is connected to flexible hose (not shown) which delivers a continuous flow of a compressible fluid.
  • compressible fluids are gases and may be accelerated to supersonic flow through a converging-diverging nozzle.
  • Grooves 13 and 14 are adapted to be received by a quick disconnect mechanism (not shown) attached to the hose delivering the flow of compressible fluid.
  • the interior cavity (not shown) of nozzle inlet 10 changes from a circular cross section to a rectangular cross section along the length of nozzle inlet 10 to where it is delivered into inlet 7 of supersonic passageway 6.
  • the static pressure of the flow at the exit will be equal to 0 psig, or stated another way, will be equal to the static ambient pressure.
  • a nozzle which has a lower static pressure at exit 9 is referred to as an overexpanded - underdeveloped nozzle. In such an overexpanded nozzle, the static pressure of the flow reaches 0 psig at a point upstream of the exit. This reduces the efficiency of the nozzle in terms of maximizing the momentum of the flow exiting the nozzle.
  • shock waves form in such supersonic flow as present here at the point at which the static pressure of the flow is equal to 0 psig.
  • shock waves are formed externally at the exit, and travel from the supersonic passageway. It is these shock waves which produce the high sound pressure level of a supersonic nozzle while it is operating.
  • the present embodiment of the invention lowers the noise generated by the supersonic nozzle 1 by overexpanding the nozzle.
  • the flow through the supersonic nozzle 1 reaches 0 psig static pressure at location 18. It is at this point in supersonic passageway 6 that shock waves form.
  • the shock waves are attenuated as they travel from location 19 through exit 9 and out to the ambient environment.
  • the noise level is reduced by this design.
  • exit to throat ratio which is the ratio of the cross sectional area of exit 9 to the cross sectional area of throat 8.
  • isentropic flow no losses
  • the ratio of 2.77 theoretically achieves 0 psig static pressure at the exit.
  • ideal flow no losses
  • the actual ratio which produces 0 psig static pressure is in fact less than 2.77.
  • an exit area to throat area ratio of 2.48 will produce a static pressure of 0 psig at the exit.
  • an exit area to throat area ratio of greater than 2.5 is necessary.
  • the inventors have determined that, as a practical matter, an exit area to throat area ratio of greater than 6.0 is impractical due to boundary layer separation turbulence and the potential of stalling the nozzle.
  • another embodiment of the present invention also includes grooves 17 formed in the exterior wall 16 of supersonic passageway 6 as described above.
  • the location of these grooves 17 near exit 9 of supersonic passageway 6, assists in preventing the shock waves from coalescing with one another and thereby enhancing and re-enforcing themselves.
  • Grooves 17 are shown as extending upstream from exit 9 to the point along the length of supersonic passageway 6 at which 0 psig static pressure occurs in the flow. If grooves 17 were to extend beyond this point, there would be some loss in efficiency of the nozzle without any corresponding gain in sound attenuation. This is because the shock waves are not formed upstream of location 18, and, therefore, any portion of grooves 17 extending beyond location 18 will not be functional with respect to preventing the coalescing of shock waves.
  • grooves 17 are formed in interior wall 16, and in particular, on one set of opposing surfaces 16B, 16D.
  • This embodiment operates efficiently when the distance between the grooves 17 from ridge to ridge 17B is 762 ⁇ m to 1270 ⁇ m (.030 inches to .050 inches). It is particularly efficient when this distance is 762 ⁇ m (.030 inches). Too great of a distance will reduce the efficiency of the grooves 17 in preventing the coalescing of shock waves.
  • the depth of grooves 17 from ridge 17B to recess 17A is in the range of 127 ⁇ m to 381 ⁇ m (.005 inches to .015 inches). If the grooves 17 are too shallow, the grooves 17 are ineffective in preventing the coalescing of shock waves. If the grooves 17 are too deep, they reduce the efficiency of the nozzle.
  • supersonic nozzle 1 having a plurality of inserts 20 complementary in shape to and disposed in longitudinal cavities 20A formed in exterior surface 15. As indicated, in the present embodiment, inserts 20 are disposed on opposite exterior surfaces 15B and 15D. Inserts 20 and cavities 20A are shown as running the length of nozzle body 2, terminating at end 21 of nozzle body 2. Inserts 20 may be flush with exterior surface 15 as shown or may terminate above or below exterior surface 15. Inserts 20 may be a single piece per cavity 20A or may be layered of several inserts 20 in one cavity 20A.
  • nozzle body 2 may be formed of any suitable material, in the present embodiment it is formed of aluminum. Inserts 20 are preferably of a similar material, having a greater density than the material which forms nozzle body 2. In the present embodiment, inserts 20 are made of lead.
  • Noise generated by the operation of supersonic nozzle 1 may also travel through nozzle body 2, being absorbed and then re-emitted from the nozzle.
  • inserts 20 in cavities 20A on exterior surface 15 of nozzle body 2, the ability of nozzle body 2 to transmit the noise is reduced.
  • Inserts 20 formed of lead absorb some of the energy of the transmitted sound due to the density of the lead, and thereby reduces the transmission of sound from the surface of the lead.
  • FIG 5 An alternative embodiment to figure 5, is to form cavities 20A in exterior surface 15 of nozzle body 2 without disposing inserts in cavities 20A. As mentioned above, such discontinuity of exterior surface 15 helps to decrease the transmission of sound therefrom. However, also as described, the sound is reduced even further by filling cavities 20A with inserts 20. Although longitudinal cavities and inserts are shown, randomly sized and located cavities and inserts will also produce similar sound attenuation. Although figure 5 shows the use of cavities 20A and inserts 20 on a nozzle having grooves 17 in supersonic passageway 6, it should be understood that either may be used alone or in combination.
  • Supersonic nozzle 1 has a shield 22 disposed about a portion of exterior surface 15 of nozzle body 2.
  • the shield is formed of two portions, 22A, 22B, and is secured by a plurality of bolts 23 which also hold upper section 3 and lower section 4 of nozzle body 2 together.
  • Shield 22 is shown extending beyond exit 9 in the direction of flow.
  • Exit opening 24 is formed at end 25 of shield 22.
  • Exit opening 24 is defined by perimeter 26 and is generally aligned with exit 9 as shown in figure 12.
  • Exit opening 24 is larger than exit 9, and as shown, is preferably at least 25% larger than exit 9.
  • Figure 8 shows a side elevational view of shield portion 22B.
  • shield 22B has sides 27A and 27B extending perpendicularly from wall 28.
  • Relief 29 is shown formed in wall 28, resulting in steps 30A and 30B formed adjacent sides 27A and 27B, respectively.
  • End 31 is formed between side 27A, wall 28, and side 27B at one end of shield 22B.
  • a portion of perimeter 26 is formed by end 31.
  • symmetrical shields 22A and 22B are assembled about nozzle body 2, with spacers 33 located between exterior surface 15 and steps 30A and 30B, thereby preventing any direct contact between shield 22 and nozzle body 2.
  • the distance between sides 27A and 27B is greater than the distance between exterior surfaces 15A and 15C, also preventing any direct contact between shield 22 and nozzle body 2.
  • shield 22 in partial cross section as disposed about nozzle body 2 of supersonic nozzle 1.
  • Exit cavity 34 is defined by exit 9 of supersonic passageway 6, shield 22A, 22B, and exit opening 24.
  • Exit cavity 34 is defined by exit 9 of supersonic passageway 6, shield 22A, 22B, and exit opening 24.
  • Formed between shield 22 and exterior surface 15 is an air cavity or gill cavity 35 which communicates with the ambient environment at gill opening 36 at one end, and with exit cavity 34 at the other end.
  • the size of gill cavity 35 is further enhanced by the spacing of shield 22A, 22B from exterior surface 15 by a plurality of spacers 33, and by relief 29 of shield 22B and the corresponding symmetrical relief of shield 22A.
  • shield 22 By assembling shield 22 to surround nozzle body 2 as shown in figures 6, 11, and 12, additional sound attenuation is achieved.
  • the transmission of sound from exterior surface 15 of nozzle body 2 is reduced due to the spacing of shield 22A, 22B from exterior surface 15. Sound which reaches shield 22A, 22B is reflected and absorbed by the interior surface 37A of shield 22 and only a portion of the sound is re-emitted from the exterior surface 37 of shield 22.
  • exit cavity 34 acts to attenuate the shock waves emerging with the flow from exit 9 prior to exiting through exit opening 24.
  • exit opening 24 It is important that exit opening 24 not act as the exit of supersonic nozzle 1. To prevent this, an auxiliary air flow passes through gill cavity 35, and exits through exit opening 24 in combination with the supersonic flow from exit 9.
  • the supply of auxiliary air through gill cavity 27 must be sufficient to prevent any effect of exit cavity 34 on the actual supersonic flow at exit 9. Satisfactory auxiliary air flow has been achieved in practice by maintaining the depth of relief 29 formed in shield 22A and 22B at .050 inches.
  • the auxiliary air flow mixes with the supersonic air flow while exiting through exit opening 24. To prevent turbulence and other undesirable effects, it is best if the mixing of the two flows occurs as tangentially as possible. To this end, it has been determined that optimum results are obtained if the angle 38 formed between exterior surface 15 at end 39 of nozzle body 2 and perimeter 26 be no less than 60°, although the nozzle 1 is operable with an angle 38 of less than 60°. Angle 38 is called the gill angle.
  • the nozzle body will be formed of aluminum.
  • Shield 22 may be formed of brass or other similar material.
  • Spacers 33 are formed of a fiber material, having poor sound transmission properties, to reduce the transmission of sound from exterior surface 15 through spacers 33 to shield 22. While it is anticipated that shield 22 be used in combination with grooves 17 and a supersonic nozzle having an exit to throat ratio in the range of 2.5 to 6.0, the shield will in fact attenuate sound independent of the presence of grooves 17. Of course, for optimum sound attenuation, the preferred embodiment encompasses all three of these features. Additionally, one skilled in the art may find improvement in the sound attenuation performance of the preferred embodiment by further disposing cavities and inserts (not shown) on exterior surface 37 of shield 22.
  • Figure 12 shows an end view of the nozzle of figure 6, with shield 22 partially cut away. As can be seen, exit opening 24 is aligned with exit 9. Gill cavity 35 extends completely around nozzle body 2 between exterior surface 15 and interior surface 37A of shield 22.
  • a nozzle according to the present invention having an exit to throat ratio of 2.69 in combination with grooves formed in the supersonic passageway as described above, will produce a sound pressure level of 112 dBA at the operator position.
  • the shield By adding the shield to this nozzle, further sound attenuation is achieved and the sound pressure level at the operator's location is reduced to as low as 104 dBA.
  • Figure 13 shows another embodiment of the present invention having an elongated nozzle body 40, with shield 41 secured near the end of the nozzle body 40 as described above in conjunction with the embodiment of figure 6.
  • Figure 14 shows another embodiment having a supersonic passageway with a circular cross section in combination with grooves formed in the interior wall of the supersonic passageway, and a shield disposed about the nozzle body, spaced therefrom.

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  • Nozzles (AREA)
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Claims (21)

  1. Schalldämpfende Überschalldüse (1), die mit einer Strömung kompressiblen Fluids verbunden ist, umfassend:
    a) ein Düsengehäuse (2) mit einer Außenfläche (15); und
    b) einen Überschalldurchgang (6) mit einer Innenwandung (16), wobei dieser Überschalldurchgang (6) in diesem Düsenkörper (2) ausgebildet ist und über einen Einlaß (7), einen Hals (8) und einen Auslaß (9) verfügt, wobei dieser Überschalldurchgang (6) auch einen konvergierenden Abschnitt (19) von diesem Einlaß (7) zu diesem Hals (8) und einen divergierenden Abschnitt (19a) von diesem Hals (8) zu diesem Auslaß (9) aufweist, wobei dieser Überschalldurchgang (6) so ausgelegt ist, daß er Schallströmung an diesem Hals (8) und Überschallströmung in diesem divergierenden Abschnitt (19a) erzeugt dadurch gekennzeichnet, daß dieser Durchgang (6) weiterhin ein Verhältnis von Austrittsfläche zu Halsfläche im Bereich von 2,5 bis 6,0 hat, wobei der statische Druck der Überschallströmung an diesem Austritt (9) während des Betriebes dieser Düse (1) geringer als der statische Umgebungsdruck ist; und
    c) eine Vielzahl von Ausnehmungen (20a) in dieser Außenfläche (15) dieses Düsenkörpers (2) ausgebildet sind.
  2. Eine Düse (1) nach Anspruch 1, wobei diese Ausnehmungen (20a) in Längsrichtung in dieser Außenfläche (15) geformt sind.
  3. Eine Düse nach Anspruch 2, die weiterhin eine Vielzahl von Einsätzen (20) umfaßt, wobei diese Einsätze (20) Formen komplementär zu diesen Längsausnehmungen (20a) haben, wobei diese Einsätze (20) in diesen Ausnehmungen (20a) angeordnet sind.
  4. Eine schalldämpfende Überschalldüse (1), die mit einer Strömung kompressiblen Fluids verbindbar ist, umfassend:
    a) einen Düsenkörper (2) mit einer Außenfläche (15); und
    b) einen Überschalldurchgang (6) mit einer Innenwandung (16), wobei dieser Überschalldurchgang (6) in diesem Düsenkörper (2) ausgebildet ist und über einen Einlaß (7), einen Hals (8) und einen Austritt (9) verfügt, wobei dieser Überschalldurchgang (6) auch einen konvergierenden Abschnitt (19) von diesem Eintritt (7) zu diesem Hals (8) sowie einen divergierenden Abschnitt (19a) von diesem Hals (8) zu diesem Austritt (9) hat, wobei dieser Überschalldurchgang (6) so ausgelegt ist, daß er Schallströmung an diesem Hals (8) und Überschallströmung in diesem divergierenden Abschnitt (19a) erzeugt, dadurch gekennzeichnet, daß dieser Durchgang (6) weiterhin ein Verhältnis von Austrittsfläche zu Halsfläche im Bereich von 2,5 bis 6,0 hat, wobei der statische Druck der Überschallströmung an diesem Austritt (9) während des Betriebs dieser Düse (1) geringer als der statische Umgebungsdruck ist; und
    c) einen Schirm (22), der um diese Außenfläche (15) dieses Düsengehäuses (2) angeordnet ist und in Strömungsrichtung über diesen Austritt (9) hinaus sich erstreckt;
    d) eine durch diesen Schirm (23) gebildete Austrittsöffnung (24), wobei diese Austrittsöffnung (24) ausgerichtet bezüglich dieses Austritts (9) dieses Überschalldurchgangs (6) ist, wobei diese Austrittsöffnung (24) in der Gestalt komplementär zu diesem Austritt (9) ist und über eine Querschnittsfläche verfügt, die wenigstens so groß wie die Querschnittsfläche dieses Austritts (9) ist; und
    e) einen Austrittshohlraum (34), der definiert wird durch diesen Austritt (9) dieses Überschalldurchgangs (6), diesen Schirm (22) und diese Austrittsöffnung (24) dieses Schirms (22).
  5. Eine Düse (1) nach Anspruch 4, wobei diese Austrittsöffnung (24) wenigstens 25% größer als dieser Austritt (9) dieses Überschalldurchgangs (6) ist.
  6. Eine Düse (1) nach Anspruch 4 oder 5, die weiterhin erste Mittel (35) umfaßt, die eine Hilfsluftströmung in diese Austrittsausnehmung (34) ermöglicht, wobei diese ersten Mittel (35) Mittel umfassen, um diese Hilfsluftströmung durch diese Austrittsöffnung (24) dieses Schildes (22) austreten zu lassen.
  7. Eine Düse (1) nach Anspruch 6, wobei dieses erste Mittel (35) eine Rippenausnehmung (35) umfaßt, die zwischen dieser Außenfläche (15) und diesem Schild (22) ausgebildet ist, wobei diese Rippenausnehmung (35) mit der Umgebung an einem Ende und mit der Austrittsausnehmung (34) am anderen Ende in Verbindung steht.
  8. Eine Düse (1) nach Anspruch 7, wobei diese Austrittsöffnung (24) einen Umfang (26) hat und weiterhin einen Rippenwinkel (38) aufweist, der zwischen dieser Außenfläche (15) und diesem Umfang (26) gebildet ist, wobei dieser Rippenwinkel (38) wenigstens 60° beträgt.
  9. Eine Düse (1) nach einem der Ansprüche 4 bis 8, wobei dieser Schirm (22) nicht direkt irgendeinen Teil dieser Außenfläche (15) kontaktiert.
  10. Eine Düse nach Anspruch 9, wobei Distanzstücke (33) zwischen diesem Schirm (22) und dieser Außenfläche (15) dieses Düsenkörpers (2) angeordnet sind.
  11. Eine schalldämpfende Überschalldüse (1), die mit einer Strömung kompressiblen Fluids verbindbar ist, umfassend:
    a) ein Düsengehäuse (2) mit einer Außenfläche (15); und
    b) einen Überschalldurchgang (6) mit einer Innenwand (16), wobei dieser Überschalldurchgang (6) in diesem Düsenkörper (2) gebildet ist und über einen Einlaß (7), einen Hals (8) und einen Austritt (9) verfügt, wobei dieser Überschalldurchgang (6) auch einen konvergierenden Abschnitt (19) von diesem Einlaß (7) zu diesem Hals sowie einen divergierenden Abschnitt (19a) von diesem Hals (8) zu diesem Austritt (9) aufweist, wobei dieser Überschalldurchgang (6) so ausgelegt ist, daß er Schallströmung an diesem Hals (8) und Überschallströmung in diesem divergierenden Abschnitt (19a) erzeugt,
    dadurch gekennzeichnet, daß dieser Durchgang (6) weiterhin ein Verhältnis von Austrittsfläche zu Halsfläche im Bereich von 2,5 bis 6,0 aufweist, wobei der statische Druck dieser Überschallströmung an diesem Austritt (9) während des Betriebs dieser Düse (1) geringer als der statische Umgebungsdruck ist; und
    c) eine Vielzahl von Längsnuten (17), die in dieser Innenwand benachbart diesem Austritt (9) gebildet sind, wodurch das Koaleszieren von Stoßwellen verhindert wird, die durch die Überschallströmung während des Betriebs dieser Düse (1) in diesem Überschalldurchgang (6) erzeugt wurden.
  12. Eine Düse nach einem der Ansprüche 1 bis 10, die weiterhin eine Vielzahl von Längsnuten (17) umfaßt, die in dieser Innenwand benachbart diesem Austritt (9) ausgebildet sind, wodurch das Koaleszieren von Schallwellen verhindert wird, die durch die Überschallströmung während des Betriebs der Düse (1) in diesem Überschalldurchgang (6) erzeugt wurden.
  13. Eine Düse (1) nach einem der Ansprüche 11 oder 12, wobei diese Längsnuten (17) sich von diesem Austritt (9) nach innen gegen diesen Hals (8) bis zu der Stelle in diesem divergierenden Abschnitt (19a) erstrecken, an dem der statische Druck der Überschallströmung während des Betriebs der Düse (1) gleich dem statischen Umgebungsdruck ist.
  14. Eine Düse (1) nach einem der Ansprüche 11 bis 13 oder 13, wobei die Tiefe dieser Nuten (17) im Bereich von 127 µm bis 381 µm (0,05 englische Zoll bis 0,15 englische Zoll) beträgt.
  15. Eine Düse (1) nach einem der Ansprüche 11 bis 14, wobei der Abstand zwischen den Nuten (17) sich im Bereich von 762 µm bis 1270 µm (0,030 englische Zoll bis 0,050 englische Zoll) beträgt.
  16. Eine Düse (1) nach einem der Ansprüche 11 bis 15, wobei dieser Überschalldurchgang (6) eine längliche rechtwinklige Querschnittsgestalt hat, die durch zwei Gruppen von sich gegenüberstehenden Flächen (16a, 16b, 16c, 16d) gebildet sind, wobei diese Längsnuten (17) in einer Gruppe dieser sich gegenüberstehenden Flächen ausgebildet sind.
  17. Eine Düse (1) nach einem der vorhergehenden Ansprüche weiterhin umfassend:
    a) einen mit diesem Düsengehäuse (2) verbundenen Düseneinlaß; und
    b) einen Einlaßdurchgang in diesem Düseneinlaß, wobei der Einlaßdurchgang so ausgelegt ist, daß er die Strömung kompressiblen Fluids aufnimmt und diese Strömung kompressiblen Fluids an diesen Einlaß (7) dieses Überschalldurchgangs (6) liefert, wobei der Einlaßdurchgang einen Einlaß kreisförmigen Querschnitts sowie einen Auslaß rechtwinkligen Querschnitts aufweist.
  18. Eine Düse (1) nach Anspruch 17, wobei dieser Düseneinlaß so ausgelegt ist, daß er sich mit einem Schnellkupplungsmechanismus verbinden läßt.
  19. Eine Düse nach Anspruch 3, wobei diese Einsätze (20) sich nicht über diese Außenfläche (15) hinaus erstrecken.
  20. Eine Düse (1) nach Anspruch 3 oder 19, wobei diese Einsätze (20) aus einem Material gebildet sind, das unterschiedlich zu dem Material ist, aus dem diese Außenfläche (15) dieses Düsenkörpers (2) gebildet ist.
  21. Eine Düse (1) nach Anspruch 3, 19 oder 20, wobei diese Einsätze (20) aus einem Material gebildet sind, das dichter als das Material ist, aus dem diese Außenfläche (15) dieses Düsenkörpers (2) gebildet ist.
EP90904011A 1989-02-08 1990-02-07 Überschalldüse mit reduziertem geräusch Expired - Lifetime EP0414863B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US30817389A 1989-02-08 1989-02-08
US308173 1989-02-08
PCT/US1990/000688 WO1990009243A1 (en) 1989-02-08 1990-02-07 Noise attenuating supersonic nozzle

Publications (2)

Publication Number Publication Date
EP0414863A1 EP0414863A1 (de) 1991-03-06
EP0414863B1 true EP0414863B1 (de) 1994-07-27

Family

ID=23192867

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Application Number Title Priority Date Filing Date
EP90904011A Expired - Lifetime EP0414863B1 (de) 1989-02-08 1990-02-07 Überschalldüse mit reduziertem geräusch

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Country Link
EP (1) EP0414863B1 (de)
JP (1) JPH03504824A (de)
AT (1) ATE109030T1 (de)
DE (1) DE69011014T2 (de)
WO (1) WO1990009243A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006015805A1 (de) * 2006-04-03 2007-10-04 Alfred Kärcher Gmbh & Co. Kg Strahlmittelaustragsdüse

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5545073A (en) * 1993-04-05 1996-08-13 Ford Motor Company Silicon micromachined CO2 cleaning nozzle and method
DE4430698C1 (de) * 1994-08-30 1996-02-08 Freudenberg Carl Fa Luftschalldämpfer
JP2000210837A (ja) * 1999-01-25 2000-08-02 Yokogawa Kazuhiko 圧縮した気体を使った加工点冷却加工用ノズル
FR2850139B1 (fr) * 2003-01-16 2006-04-14 Herve Simoens Accessoire pour dispositif de decharge brusque d'air et dispositif de decharge equipe de cet accessoire
FR2977183B1 (fr) * 2011-06-29 2014-09-19 Air Liquide Dispositif de projection de glace seche, notamment de glace carbonique
TWI832028B (zh) 2019-12-31 2024-02-11 美商冷卻噴射公司 粒子噴射系統及從一噴射噴嘴排出一挾帶粒子流之方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2064003A1 (de) * 1969-12-29 1971-07-15
JPS602489B2 (ja) * 1977-05-02 1985-01-22 株式会社豊田中央研究所 低騒音用圧力流体放出装置

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006015805A1 (de) * 2006-04-03 2007-10-04 Alfred Kärcher Gmbh & Co. Kg Strahlmittelaustragsdüse
EP1842598A1 (de) 2006-04-03 2007-10-10 Alfred Kärcher GmbH & Co. KG Strahlmittelaustragsdüse

Also Published As

Publication number Publication date
ATE109030T1 (de) 1994-08-15
EP0414863A1 (de) 1991-03-06
DE69011014D1 (de) 1994-09-01
WO1990009243A1 (en) 1990-08-23
JPH03504824A (ja) 1991-10-24
DE69011014T2 (de) 1995-03-23

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