US3798475A

US3798475A - Square wedge fluidic generator for electrical and mechanical outputs

Info

Publication number: US3798475A
Application number: US00238138A
Authority: US
Inventors: C Campagnuolo; H Lee
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1972-03-27
Filing date: 1972-03-27
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19

Abstract

A fluidic generator utilizing a novel fluid intake system for achieving increased power output at low pressures. The resonating cavity of the fluidic generator is provided at its fluid intake end with a mechanical member for separating and converging fluid. The cavity is adjacent an intake orifice with the member being located inside the orifice for separating fluid flowing out of the orifice. The fluid is converged at the entrance to the cavity and ultimately fills and empties the cavity to vibrate a diaphragm at resonance for generating electrical or mechanical output signals.

Description

United States Patent [191 Campagnuolo et al.

SQUARE WEDGE FLUIDIC GENERATOR FOR ELECTRICAL AND MECHANICAL OUTPUTS Inventors: Carl J. Campagnuolo, Potomac;

Henry C. Lee, Crofton, both of Md.

The United States of America as represented by the Secretary of the Army, Washington, DC.

Filed: Mar. 27, 1972 Appl. No.: 238,138

Assignee:

US. Cl 310/15, 137/827, 137/831,

' 116/137 Int. Cl. H02k 35/06 Field of Search 137/815, 827, 831; 181/5; 102/924; 310/2, 1.5, 36,116/137; 74/88 References Cited UNITED STATES PATENTS Campagnuolo et a1....; 137/815 Kuhl 116/137 R 1 1 Mar. 19, 1974 2,954,701 10/1960 Berill 74/88 X 3,169,509 2/1965 Rich 116/137 R 3,375,840 4/1968 Fox et al l37/81.5 3,408,050 10/1968 Jacobs, lll 116/137 A 3,555,314 1/1971 Villarroel et a1 310/15 Primary Examiner-William R. Cline Attorney, Agent, or Firm-Edward J. Kelly; Herbert Bert; Saul Elbaum [57] ABSTRACT A fluidic generator utilizing a novel fluid intake system for achieving increased power output at low pressures. The resonating cavity of the fluidic generator is provided at its fluid intake end with a mechanical member for separating and converging fluid. The cavity is adjacent an intake orifice with the member being located inside the orifice for separating fluid flowing out of the orifice..The fluid is converged at the entrance to the cavity and ultimately fills and empties the cavity to vibrate a diaphragm at resonance for generating electrical or mechanical output signals.

9 Claims, 6 Drawing Figures PmEmmm 19 1914 1 SQUARE WEDGE TFLUIDIC GENERATOR FOR ELECT RICAL AND MECHANICAL OUTPUTS The invention described herein may be manufactured, used and licensed by or for the United States Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to an improved fluidic generator.

A fluidic generator is-a device which converts pneumatic .energyinto electrical and/or mechanical energy. Ingeneral a fluidic generator is comprised of a resonating cavity in whichincoming fluid is caused to oscillate,

a diaphragm in fluid connection with the resonating cavity. which is vibrated by .the force of the oscillating fluid and a means-for either utilizing the mechanical energy of the vibrating diaphragm or for converting the mechanical energyto electrical energy. The conversion means may comprise a'reed which is-connected to the diaphragm and which vibrates in the air gap of a magnetto generate an electrical signal.

'Fluidic generators may be advantageously used in a projectile or missileor other spacecraft or aircraft as a sourceofelectricalpower. If used in this way, the resonating cavity of the generator is positioned behind an opening in thebodyof the projectile and as the projectile flies through space fluid enters the opening and alternatingly fills and empties the resonating cavity to vdrive the diaphragm.

In the fluidic generators of the prior art, a nozzle having an annular'shape has been used to admit fluid into the resonating cavity. While the annularnozzle is effective tosupply a converging flow of fluid to the resonating cavity, it has the *effect of greatly restricting the mass of fluid which is allowed to enter the cavity and thereby makesthe fluidic generator a pressure dependent device. The generators of the prior art have thus required high pressure forcesto produce useable electrical outputs and have not been suitable for use with low speed projectiles. j

The present invention overcomes the above stated disadvantages by eliminating the annular entrancenozzle of the prior art, and replacing it with anovel fluid entrance system comprised of a simple orifice combined with a separating and converging means located at the intake endof the resonating cavity. The fluidic generator according to the invention is thus a high mass flow system which provides large electrical and mechanical output signals even at low pressures and thus fully utilizes the pneumatic energy available from the environment.

Itis therefore an object of the invention to provide a fluidic generator capable of producing large electrical and mechanical output signals.

It is a further object of the invention to provide a fluidic generator which can accommodate a high mass flow and produce large electrical and mechanical output signals at low pressures.

It is a furtherobject of the invention to provide a projectile or missile having a fluidic generator mounted therein which can produce large output signals when the projectile or missile is flying at low speeds.

It is a further object of the invention to provide a fluidic generator which is more simple in construction and less costly to build "than the fluidic generators of the prior art.

Theabove objects are accomplished by providing a fluidic generator having a novel fluid intake system comprised of a simple orifice combined with a means located at the intake end of the resonating cavity for separating and converging incoming fluid. In a preferred embodiment of the invention, the means for separating and converging comprises a member which extends across the center of the open end of the cavity at the fluid intake end of the cavity in contact with the orifice for separating fluid exiting from the orifice. The member is located in front of the entrance to the cavity and is supported at each end by the forwardmost portions of the edges of the cavity, the remainder of the edges being sharp and extending rearwardly to form the entrance to the cavity. Some of the incoming fluid which has been separated by the member encounters the sharp edge of the entrance and enters the cavity. Separation of the fluid further causes a low pressure region to form directly behind the member and this causes the outer streamlines of the fluid to converge at the entrance and flow into the cavity. The incoming fluid periodically fills and empties the resonating cavity to vibrate the diaphragm and produce mechanical and electrical output'signals.

The invention will be better understood after reading the following description of a preferred embodiment when taken in conjunction with the drawings in which:

FIG. 1 is a perspective view with portions broken away for the sake of illustration of a fluidic generator of the prior art mounted in a projectile or missile.

FIG. 2 is a perspective view with portions broken away for the sake of illustration of a fluidic generator according to the invention mounted in a projectile or missile.

FIG. 3 is a sectional viewof the intake end of the resonating cavity of the fluidic generator of FIG. 2

FIGS. 4 and 5 are pictorial illustrations of the way in which the intake system of the invention causes the fluid streamlines of the incoming fluid to separate and converge. 1

FIG. 6 is a side view of a safing and arming system being powered by the fluidic generator of the invention.

FIG. 1 shows a fluidic generator of the prior art mounted in a projectile or missile. Fluidic generator 2 which is comprised of collar 4, cylindrical centerbody 5, and resonating cavity 6 is mounted in opening 3 in the forward portion of projectile ormissile l. Collar 4 is secured in opening 3 and in the body of the missile, only a portion of which is shown by any conventional securing means as would be known to one skilled in the art. Resonating cavity 6 is in fluid communication with displaceable diaphragm 7 which is eausedto vibrate at resonance by fluid filling and emptying cavity 6. Diaphragm 7 is connected to reed 9, which is a cantilevered strip of soft iron or mild steel, by connecting rod 8, and reed 9 vibrates in the air gap of magnet 10 and within coil 11 to generate a voltage in coil 11 when the diaphragm vibrates. If desired, the mechanical motions of connecting rod 8 or other mechanical means attached to the diaphragm 2-may be directly used, for inannulus comprises the annular nozzle utilized by the prior art to admit fluid to the resonating cavity. As the projectile or missile flies, fluid is admitted to collar 4 and is separated by centerbody 5 to create a low pressure region at the center of the stream. This low pressure region induces the outer jets streamlines to converge beyond the centerbody thereby reducing the effective jet diameter. The intake end of resonating cavity 6 is set back from the centerbody so that the converging stream enters the cavity. The resulting pressure increase inside the cavity expels the stream and entrainment then lowers the pressure inside the cavity. Due to the low pressure in the cavity, the process is then repeated whereby a cyclical filling and emptying of resonating cavity is induced which is effective to vibrate diaphragm 7 at resonance and to produce an output voltage in coil 11.

Because the annular nozzle of FIG. 1 admits relatively small masses of air to resonating cavity 6, the prior art fluidic generator of FIG. 1 is a pressure dependent device which can only generate useable electrical signals at relatively high intake pressures and which is therefore not suitable for use with projectiles flying at low speeds. According to the invention, as shown in FIGS. 2-6, a novel fluid intake system is provided which enables larger mass flow to be accommodated and allows high output electrical and mechanical signals to be generated even at low pressures.

In FIG. 2 fluidic generator 21 is shown mounted inside of projectile or missile 20. Fluidic generator 21 would be supported in the interior of the forward portion of projectile or missile by any conventional mechanical support means as would be known to one skilled in the art. Fluidic generator 21 is comprised of tube 22 and resonating cavity 24 which comprise an integral system. Tube 22 is mounted in opening 23 of missile 20 and the exit end of tube 22 provides an orifice for fluid flowing into the resonating cavity. At its fluid intake end resonating cavity 24 has member 25 disposed completely across the center of the open end space of the cavity defined by the edge of the cavity which is comprised of

edge portions

26 and 27.

Edge portions

26 and 27 support member 25 at their forwardmost areas at each end of member 25 and the remainder of

edge portions

26 and 27 extend rearwardly to provide an entrance for resonating cavity 24.

In the preferred embodiment of the invention, member 25 is a,wedge-like member having diverging

surfaces

28 and 29 as is shown in FIG. 3. In the operation of the device, resonating cavity 24 is placed adjacent to tube 22 so that the member 25 is located in the exit end of tube 22. Resonating cavity 24 is supported in this position by conventional means and is shown separated from tube 22 in the drawings only for purposes of illustration.

It is thus seen that an advantage of the invention is that it does away with the collar used in the prior art shown at 4 in FIG. 1 and is thus simple mechanically and less costly to build than the prior art fluidic generator.

As fluid flows out of tube 22 it encounters member 25 and is separated into two halves as is shown in FIG. 4. Because of the location of the entrance to the cavity with'respect to member 25, part of the separated fluid encounters

sharp edge portions

26 and 27 and flows into the cavity. Because of the separation of the fluid by member 25 a low pressure region is created directly behind member 25. This low pressure region causes the outer fluid streamlines to converge at the entrance to the cavity as shown in FIG. 5. The fluid entering the cavity fills the cavity until the pressure within the cavity becomes greater than atmospheric pressure, when fluid leaves the cavity thus lowering the pressure. When the pressure in the cavity becomes lower than atmosphere, the fluid returns to the cavity and a new cycle initiates. The member 25 which creates a fluid instability condition at the intake end of the cavity contributes to the triggering mode of the oscillator. The diaphragm is vibrated at resonance as fluid alternately fills and empties the cavity and, as described with respect to the configuration shown in FIG. 1, electrical or mechanical output signals are produced.

While a wedge-like member with diverging surfaces is used for member' 25 in the preferred embodiment of the invention, it is to be understood that it is within the scope of the invention to use any mechanical member at the fluid intake end of the cavity for the purpose of separating and converging fluid flow. Also while tubes of circular crosssection are used for tube 22 and resonating cavity 24 it is within the scope of the invention to use tubes of any arbitrary cross-section for either or both of

tubes

22 and 24. For instance, tubes of rectangular cross-section can be used.

As used in the claims of this invention, the term electrical or mechanical signals" is to be construed as meaning either electrical signals or mechanical signals, or both electrical and mechanical signals and the term aircraft or spacecraft is to be construed as including a projectile or missile.

The mechanical output signals of the fluidic generator according to the invention may be utilized as shown in FIG. 6 to drive a mechanical safing and arming system. Curved reed 35 is attached to reed 31 or in the alternative,

reeds

31 and 35 may comprise a single integral unit. As

reeds

31 and 35 vibrate reed 35 rotates gear 36 which is meshed with larger gear 37 which in turn moves a slider 38 containing a detonator in line as is known to those skilled in the art.

It should be understood that the invention is not limited to the exact details of construction shown and described herein for obvious modifications will occur to persons skilled in the art.

We claim:

1. In a fluidic generator comprising a resonating cavity for receiving flowing fluid, which cavity is permanently closed except for an open fluid intake end space which is defined by the extreme edge of said cavity at said intake end, said end space being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for utilizing the energy of the displacements of said diaphragm, the improvement comprising:

said open end space of said resonating cavity including means disposed therein for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity whereby periodic alterations of flow are induced in said resonating cavity for displacing said diaghragm, said means for separating comprising a member which extends completely across the center of said open end space and which occupies an area which is less than the total cross-sectional area of said cavity, said member having two ends, each of which is secured to said extreme edge of said cavity.

, the forwardmost portions of said edge, the remainder of said edge extending rearwardly of said member.

4. A low pressure,'high mass-flow fluidic generator for generating high magnitude electrical or mechanical signals, comprising, an orifice for receiving flowing fluid, a resonating cavity which is permanently closed except for an open fluid intake end space which is defined by the extreme edge of said cavity at said intake end, a means for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity being disposed in said open end space, said means being located in proximity to said orifice whereby fluid flowing out of said orifice is separated and later converged, said means for separating comprising a member which extends completely across the center of said open end space and which occupies an area which is less than the total cross-sectional area of said cavity, said member having two ends, each of which is secured to said extreme edge of said cavity, said resonating cavity being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for generating signals in response to the displacement of said diaphragm.

5. In a fluidic generator comprising a resonating cavity for receiving flowing fluid, which cavity is permanently closed except for an open fluid intake end, and which is mounted in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for utilizing the energy of the displacements of said diaphragm, the improvement comprising:

said open fluid intake end of said resonating cavity including means disposed therein for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity whereby periodic alterations of flow are induced in said resonating cavity for displacing said diaphragm, said means for separating comprising a member which extends across the center of said open end of said cavity at said fluid intake end and occupies an area which is less than the total cross-sectional area of said cavity, said member being supported at each end thereof in said open end of said cavity by the forwardmost areas of the edge portions of said cavity at said open end, the remainder of said edge portions extending rearwardly of said member to form an entrance to said cavity, said entrance being positioned so that a portion of said separated fluid, as well as said converged fluid flows through said entrance, a circular orifice mounted upstream of said open end of said cavity, said cavity being positioned with respect to said orifice so that said member is adjacent said orifice and so that it divides the cross-sectional area of said orifice in half.

6. The fluidic generator of claim 5 wherein said member comprises a wedge-like member having two surfaces which diverge in the direction of the rear of said cavity.

7. The fluidic generator of claim 6 wherein said remainder of said edge portions are relatively sharp and wherein said cavity and said orifice are circular in cross-section.

8. A low pressure, high mass-flow, fluidic generator for generating high magnitude electrical or mechanical signals, comprising, an orifice for receiving flowing fluids, a resonating cavity which is permanently closed except for an open fluid intake end, a means for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity being disposed in said open end, said means being located in proximity to said orifice whereby fluid flowing out of said orifice is separated and later converged, said means for separating comprising a member which extends across the center of said open end of said cavity at said fluid intake end and occupies an area which is less than the total cross-sectional area of said cavity, said resonating cavity being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for generating signals in response to the displacement of said diaphragm, a tube having an open entrance end and an open exit end, said orifice comprising the open exit end of said'tube, said member being located adjacent said open exit end of said tube for separating fluid exiting from said tube.

9. The fluidic generator of claim 8 wherein said signals are electrical signals and said means for generating said signals includes a magnet having an air gap, a reed, and an electrical conductor located in proximity to said air gap and said reed, said reed being mechanically connected to said diaphragm and being movable with said air gap for inducing an electrical signal in said conductor, whereby when said diaphragm is displaced an electrical signal is induced in said conductor.

Claims

1. In a fluidic generator comprising a resonating cavity for receiving flowing fluid, which cavity is permanently closed except for an open fluid intake end space which is defined by the extreme edge of said cavity at said intake end, said end space being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for utilizing the energy of the displacements of said diaphragm, the improvement comprising: said open end space of said resonating cavity including means disposed therein for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity whereby periodic alterations of flow are induced in said resonating cavity for displacing said diaghragm, said means for separating comprising a member which extends completely across the center of said open end space and which occupies an area which is less than the total cross-sectional area of said cavity, said member having two ends, each of which is secured to said extreme edge of said cavity.

2. The fluidic generator of claim 1, further including a circular orifice mounted upstream of said open end space of said cavity, said cavity being positioned with respect to the said orifice so that said member is adjacent said orifice and so that it divides the cross-sectional area of said orifice in half.

3. The fluidic generator of claim 2, wherein each of said two ends of said member is secured to said edge at the forwardmost portions of said edge, the remainder of said edge extending rearwardly of said member.

4. A low pressure, high mass-flow fluidic generator for generating high magnitude electrical or mechanical signals, comprising, an orifice for receiving flowing fluid, a resonating cavity which is permanently closed except for an open fluid intake end space which is defined by the extreme edge of said cavity at said intake end, a means for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity being disposed in said open end space, said means being located in proximity to said orifice whereby fluid flowing out of said Orifice is separated and later converged, said means for separating comprising a member which extends completely across the center of said open end space and which occupies an area which is less than the total cross-sectional area of said cavity, said member having two ends, each of which is secured to said extreme edge of said cavity, said resonating cavity being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for generating signals in response to the displacement of said diaphragm.

5. In a fluidic generator comprising a resonating cavity for receiving flowing fluid, which cavity is permanently closed except for an open fluid intake end, and which is mounted in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for utilizing the energy of the displacements of said diaphragm, the improvement comprising: said open fluid intake end of said resonating cavity including means disposed therein for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity whereby periodic alterations of flow are induced in said resonating cavity for displacing said diaphragm, said means for separating comprising a member which extends across the center of said open end of said cavity at said fluid intake end and occupies an area which is less than the total cross-sectional area of said cavity, said member being supported at each end thereof in said open end of said cavity by the forwardmost areas of the edge portions of said cavity at said open end, the remainder of said edge portions extending rearwardly of said member to form an entrance to said cavity, said entrance being positioned so that a portion of said separated fluid, as well as said converged fluid flows through said entrance, a circular orifice mounted upstream of said open end of said cavity, said cavity being positioned with respect to said orifice so that said member is adjacent said orifice and so that it divides the cross-sectional area of said orifice in half.

8. A low pressure, high mass-flow, fluidic generator for generating high magnitude electrical or mechanical signals, comprising, an orifice for receiving flowing fluids, a resonating cavity which is permanently closed except for an open fluid intake end, a means for separating incoming fluid and for converging said fluid at a downstream area of said closed cavity being disposed in said open end, said means being located in proximity to said orifice whereby fluid flowing out of said orifice is separated and later converged, said means for separating comprising a member which extends across the center of said open end of said cavity at said fluid intake end and occupies an area which is less than the total cross-sectional area of said cavity, said resonating cavity being in fluid connection with a diaphragm which is displaceable by the force of said flowing fluid, and means for generating signals in response to the displacement of said diaphragm, a tube having an open entrance end and an open exit end, said orifice comprising the open exit end of said tube, said member being located adjacent said open exit end of said tube for separating fluid exiting from said tube.