US3578012A

US3578012A - Flueric device

Info

Publication number: US3578012A
Authority: US
Inventors: Cheng-Kuo Weng
Original assignee: Singer General Precision Inc
Current assignee: Kearfott Guidance and Navigation Corp
Priority date: 1969-04-02
Filing date: 1969-04-02
Publication date: 1971-05-11
Anticipated expiration: 1988-05-11

Abstract

A flueric device comprising a deflection chamber having at least two outlet receivers and a supply nozzle adapted to introduce supersonic fluid flow into said deflection chamber. Control means are provided to selectively deflect the fluid flow in the chamber between the two outlet receivers.

Description

United States Patent Inventor Cheng-Kuo Weng Fair Lawn, NJ.

Apr. 2, 1969 May 11, 1971 Singer General Precision, Inc. Little Falls, NJ.

App]. No. Filed Patented Assignee FLUERIC DEVICE 4 Claims, 7 Drawing Figs.

US. (I

1nt.Cl .1: Field ofSearch References Cited UNITED STATES PATENTS 3,135,291 6/1964 Kepleretal.

137/8l.5 FlSc 1/04 137/81.5

3,212,515 10/1965 Zisfein et a1. 137/81.5 3,262,466 7/ 1966 Adams et a]. 137/81.5 3,263,695 8/1966 Scudder et al. 137/81.5 3,285,262 11/1966 Ernst et a1 137/815 3,421,324 1/1969 Bains 137/81.5X 3,428,066 2/1969 Herr 137/81.5 3,472,255 10/1969 Fox et a1. 137/81.5

Primary Examiner-Samuel Scott Attomeys-S. A. Giarrantana, G. B. Oujevolk and S. M.

Bender .ABSTRACT: A flueric device comprising a deflection chamber having at least two outlet receivers and a supply nozzle adapted to introduce supersonic fluid flow into said deflection chamber. Control means are provided to selectively deflect the fluid flow in the chamber between the two outlet receivers.

PATENIm Hm I is" 3578.012

sum 1 OF 2 ig u'fllmHU Z10 INVENTOR CHENG-KUO WENG AT TORNE YS FLUERIC DEVICE BACKGROUND OF THE INVENTION The present invention relates to a flueric device, and, more particularly, to such a device that can be used as a transonic, beam-deflected, bistable flueric amplifier, or as an electricalto-flueric converter.

Flueric amplifiers have been proposed that have a supply nozzle supplying a power jet of fluid to a deflection chamber, which power jet is deflected between two outlet receivers by selectively supplying a pair of control nozzles with fluid. However, in these known arrangements, a relatively high pressure is required in the control nozzles in order to effect switching of the power jet, and the ratio of the output flow from the receivers to the flow required at the control nozzles is relatively low. This, of course, results in relative inefficient operation and renders the output from the receivers far from ideal for staging with other receivers, etc.

Electrical-to-flueric converters having a similar basic arrangement as the amplifier discussed above, but differing in the arrangement of the control means, have also been proposed. For example, electromagnetic forces have been utilized to switch the power jet by mechanically changing the cross-sectional area of the passage. Also, two temperature sensitive pneumatic resistors have been positioned inside the control port, their resistance varying as a function of the electrical voltage input causing a corresponding change in the differential output pressure. Other converters of the same general type include those utilizing two heating members attached to the walls immediately downstream of the power jet, the variation of the differential output pressure being caused by the boundary layer separation at the heating members. Still another proposal utilizes an emitter to ionize the power jet which is then deflected by a pair of screen electrodes, the differential pressure output being proportional to the electrical voltage input within a small range of power jet deflection. Another arrangement utilizes a high voltage electrical spark to induce a pressure wave to switch the fluid flow from one output port to the other.

The common disadvantages associated with all of these type converters is a limited output power, a relatively long switching time, and a relatively large amount of electrical energy consumption. The arrangement utilizing a mechanical change of the cross-sectional area of the passage also has a limited service life, a reduced response and reliability, and an increased manufacturing cost. The proposals utilizing resistors and heating elements also require a finite time to change their resistance, while the drive utilizing the ionized gas requires a relatively high temperature. In the proposal using an electrical spark, the pressure action on the power jet must develop enough differential force to deflect it in order to switch the jet, and the control port cross-sectional area must therefore be increased to provide the necessary pressure-exerting area against the jet. This increase of the control port cross-sectional area consequently increases the control port volume, which not only requires the high voltage sparks to release more pressure and energy for switching the jet, but also slows down the switching rate.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fluidic amplifier of the above described type which requires a relatively low pressure at the control nozzle for switching the input power jet, and has a relatively high ratio of output flow to control nozzle flow.

It is a further object of the present invention to provide an electrical-to-flueric converter which enables a power jet to be switched at a relative high speed by a relatively low amount of electrical energy, and which enjoys a relatively high pneumatic power output.

Briefly summarized, the device of the present invention comprises a deflection chamber having at least two outlet receivers, a supply nozzle adapted to introduce supersonic fluid flow into said deflection chamber, and control means responsive to an input signal fluid for deflecting said fluid flow in said chamber between said two outlet receivers. The device may be utilized as an amplifier in which case the control means would be in the form of nozzles disposed on either side of the fluid flow and adapted to discharge fluid into said fluid flow, or as an electrical-to-flueric converter in which case the control means would be in the form of a spark discharge device disposed on either side of said fluid flow.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring specifically to FIG. 1, the reference numeral 10 designates a body or plate of plastic material, or the like, in which a bistable fluidic amplifier is formed by machining or etching in a known manner. As shown, a convergent-divergent power nozzle 12 is provided which has an entrance 14, a throat l6, and an exit 18, and which is adapted to supply a jet of fluid at supersonic flow to a deflection chamber shown in general by the reference numeral 20.

A pair of

receivers

22 and 24 register with the deflection chamber 20 and are divided by a splitter 26 so that fluid flow from the power nozzle 12 passes through the deflection chamber and into one or the other of the two receivers, and from the latter, through a

restricted output port

28 or 30 formed at the exit end of the

receivers

22 and 24, respectively. This fluid flow from the power nozzle 12 through the amplifier will hereafter be termed a power jet."

A pair of

control nozzles

32 and 34 are provided to supply fluid at a predetennined flow and pressure through their

exit portions

36 and 38. These exit portions, together with the exit 18 of the power nozzle, the

exits

36 and 38 of the control nozzles, and the entrances to the

receivers

22 and 24, all register with a mixing zone 40 in the deflection chamber 20.

According to one of the main features of the present invention, the pressure in the power nozzle 12 and the control nozzles 32 and 34' is regulated so that the ratio of the pressure in each

exit portion

36 and 38 to the pressure of the fluid at the exit 18 is between 0.3 and 0.7, this being possible due to the supersonic flow of the power jet and the design of the

control nozzles

32 and 34, the power nozzle 12, and the

output ports

28 and 30. It has been determined that this particular pressure ratio enables a relatively low pressure in either control nozzle to effect switching of the power jet by gradually building up a local pressure atthe power jet near its intersection with the exit to the control nozzles, resulting in a separation of the fluid jet from the corresponding power nozzle wall immediately adjacent the exit of the active control nozzle. This, in tum,'induces discontinuities into the power jet and initiates a cornpression wave to switch the power jet from the particular receiver in which the fluid is flowing to the other receiver, in a known manner.

According to an additional feature of the present invention, the

restricted output ports

28 and 30 of the

receivers

22 and 24, respectively, introduce a normal shock wave in an area immediately adjacent the entrance to the

receivers

22 and 24, as shown by 42 in the receiver 22. The exact location of the shock wave 42 is determined by the ratio of the area of the output port to the nozzle throat area, which ratio should be between 1.2 and 3.0 according to the present invention. As a result of this shock wave, the supersonic flow in the mixing zone 40 is reduced to subsonic flow in the respective receiver, which results in a relatively high fluid pressure in the receiver. This high pressure renders the power jet in the particular receiver relatively unstable so that it is relatively easy to switch in accordance with the above.

In operation, the power nozzle supplies fluid at supersonic flow into the mixing zone 40, and, assuming that the initial conditions are such that the flow passes into the left receiver 22, a normal shock wave is induced in this receiver by the restricted output port 28 which reduces the power jet flow to subsonic and therefore renders it relatively unstable. When it is desired to switch the power jet to the receiver 24, fluid flow is introduced in the control nozzle 32 which builds up the pressure near the power jet and initiates a compression wave as discussed above, to cause a resulting switching of the power jet to the right receiver 24.

As an example'of the application of above amplifier, it has been ascertained that with a power jet pressure of 100 p.s.i.g., switching will occur at a relatively low value of approximately 0.25 p.s.i.g., in the control nozzle 32 or the control nozzle 34. The pressure at the exit 18 of the power nozzle 12 would be approximately 0.18 p.s.i.g., and the flow gain, which is the ratio between the flow (in cubic feet per minute, for example) at the output port 28 to the flow at the control nozzle, is I00.

Since the prior art devices require much more pressure than 0.25 p.s.i.g., in the control nonle, and since the flow gain ratio of these known devices is usually l or less, it is apparent that the amplifier disclosed above achieves distinct advantages over the prior art.

In the embodiments of FIGS. 2A-2C and 3A-3C, the fluen'c device of the present invention is utilized as an electrical-to-flueric converter. Since the basic device is identical to that shown in FIG. 1, with the exception of the control nozzles, identical parts will be given similar reference numerals.

According to the embodiment of FIGS. 2A-2C, a pair of

control chambers

50 and 52 are provided which register with the mixing zone 40 of the deflection chamber.

Electrodes

54 and 56 are provided in the

chambers

50 and 52, respectively it being understood that the electrodes are of a high voltage, spark type well known in the art.

Upon the application of an input voltage from a power source (not shown) to either of the

electrodes

54 and 56, the latter will initiate a spark which creates energy to induce a compression pressure which travels towards the power jet, and causes the local pressure to build up at the power jet, resulting in a separation of the power jet from the power nozzle wall immediately adjacent the exit of the active control nozzle. This, in turn, induces discontinuities into the power jet and initiates a compression wave to switch the'power jet from the particular receiver in which the fluid is flowing to the other receiver, as described in connection with the amplifier above. Therefore, assuming that the power jet is flowing from the power noule 12 in the left side receiver 22 in the direction shown by the arrow A in FIG. 2A, the electrode 54 would be tired to induce a compression pressure, as indicated by the reference numeral 60 in FIG. 2A, which induces discontinuities into the power jet to initiate a compression wave 62 as shown in FIG. 2B. This compression wave causes a switching of the power jet to the right receiver 24, as shown in FIG. 2C, the output power jet then passing outwardly through the latter receiver as shown by the arrow B.

As in the previous embodiment, a normal shock wave 42 is induced in the left-hand receiver 22 to render the power jet relatively unstable, thus permitting it to be switched more easily, and the ratio of the pressure at the exit portions of the

control chambers

50 and 52 to the pressure at the exit of the power nozzle 12, is maintained at between 0.3 and 0.7, the advantages of the latter being discussed in detail above.

The embodiment of FIGS. 3A-3C is identical to that of FIGS. 2A--2C with the exception that a pull switching mode is utilized by means of the spark energy released from the

electrodes

54 and 56. This spark energy creates a compression pressure which passes through the mixing zone 40 before it strikes the power jet, whereby it is partially reflected back from the power jet boundary and travels away from the power jet thus creating a vacuum to cause switching of the power jet. in particular, and assuming the power jet is flowing through receiver 22 in the direction indicated by the arrow A in FIG. 3A, a spark is released by the electrode 56 in the control chamber 52, and the compression pressure initiated by the spark travels toward the power jet in a direction from right to left as shown by reference numeral 60 in FIG. 3A. After passing through the mixing zone 40 the compression pressure intersects the power-jet which, in effect, is essentially a constant pressure boundary to the incoming compression pressure. The latter is thus partially transmitted through the boundary and partially reflected back from the boundary as a rarefaction pressure 64 shown in FIG. 3B, which travels in an opposite direction, i.e., from left to right, through the mixing zone 40 back towards the control chamber 52. The pressure of the region behind the rarefaction pressure 64 will have the same magnitude as the incoming compression pressure, but will be of an opposite sign, thus creating a vacuum pressure within the entire region behind the rarefaction wave, i.e., the entire section of the power jet boundary that is exposed to the right control chamber 52. As a result of this differential pressure created across the power jet, the power jet is switched to the right receiver 24, and flows outwardly through the receiver in the direction indicated by the arrow B in FIG. 3C. Again, a shock wave is induced in the receiver 22 and the ratio of the pressure at the exit portions of the control chambers to the pressure at the exit of the power noule 12 is maintained at between 0.3 and 0.7.

It is apparent that the principles of FIGS. 2 and 3 can be combined into a push/pull" system wherein a spark from the control chamber immediately adjacent the receiver in which the power jet is flowing is initiated to create a push mode, while a finite time later, such a microsecond, the electrode in the opposite control chamber is energized to create a pull mode, thus enabling the switching to occur at a much faster rate than heretofore pomible.

In both of the embodiments of FIGS. 2A-2C and 3A3C it is understood that the spark discharge passages in the

control chambers

50 and 52 are designed so that any rarefaction waves within the chambers are cancelled.

The advantages of the embodiments in FIGS. 2 and 3 are numerous. For example, the required electrical energy for switching a power jet of the same pneumatic power is less than 0.2 percent of the amount needed of the above mentioned prior art device utilizing a high voltage electrical spark. Also, the size of the control chamber can be reduced to a size that is approximately equal to or less than the supply nozzle throat area, whereby in the prior art device mentioned immediately above, the control chamber size must be at least 2 times the size of the supply nozzle throat area. Also, the overall maximum percentage of pressure recovery of the present arrangement is higher than that of the conventional converters, and the maximum output pressure and pneumatic power output per unit weight of the device is over 5 times higher than that obtainable with conventional converters. Further, the switching time is as much as 10 times faster than that of the conventional converters, and an extremely small amount of electrical energy, i.e., 0.01 joules/pneumatic watt is needed to switch the power jet as compared to approximately 4 joules/pneumatic watt required by the prior art device using electrodes. Still further, a supply pressure of as high as p.s.i.g. can be switched utilizing the converter of the present invention, whereas in the prior art converters the supply pressure is limited to 25 p.s.i.g. or less.

Of course, variations of the specific construction and arrangement of the device disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

Iclaim:

l. A flueric device comprising a deflection chamber having at least two outlet receivers, a supply nozzle adapted to introduce supersonic fluid flow into said deflection chamber, a pair of control chambers registering with said deflection chamber on either side thereof, spark discharge means disposed in each saidcontrol chambers and responsive to an input signal for inducing compression pressure on said flow to deflect said 'flow in between said two outlet receivers, and means for inducing a normal shock wave in at least one of said output receivers near the entrance thereof.

2. The device of claim 1 wherein said spark discharge means are adapted to be selectively actuated to push said fluid flow

Claims

1. A flueric device comprising a deflection chamber having at least two outlet receivers, a supply nozzle adapted to introduce supersonic fluid flow into said deflection chamber, a pair of control chambers registering with said deflection chamber on either side thereof, spark discharge means disposed in each said control chambers and responsive to an input signal for inducing compression pressure on said flow to deflect said flow in between said two outlet receivers, and means for inducing a normal shock wave in at least one of said output receivers near the entrance thereof.

2. The device of claim 1 wherein said spark discharge means are adapted to be selectively actuated to push said fluid flow between said outlet receivers by means of said compression pressure.

3. The device of claim 1 wherein said spark discharge means are adapted to be selectively actuated to pull said fluid flow between said outlet receivers by means of a reflection from said compression pressure.

4. The device of claim 1 wherein said spark discharge means are adapted to be selectively actuated to push and pull said fluid flow between said outlet receivers by means of said compression pressure and a reflection from said compression pressure, respectively.