US3606901A - Monostable fluidic switch - Google Patents

Monostable fluidic switch Download PDF

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Publication number
US3606901A
US3606901A US3606901DA US3606901A US 3606901 A US3606901 A US 3606901A US 3606901D A US3606901D A US 3606901DA US 3606901 A US3606901 A US 3606901A
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United States
Prior art keywords
wall
fluid
pressure
chamber
jet
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Expired - Lifetime
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English (en)
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Raymond V Thompson
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Colt Industries Operating Corp
Colt Industries Inc
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Chandler Evans Inc
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Assigned to COLT INDUSTRIES OPERATING CORPORATION, A CORP. OF DE reassignment COLT INDUSTRIES OPERATING CORPORATION, A CORP. OF DE MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE ON 10/24/1986 DELAWARE Assignors: CHANDLER EVANS INC., A DE CORP., HOLLEY BOWLING GREEN INC., A DE CORP., LEWIS ENGINEERING COMPANY, THE, A CT CORP.
Assigned to COLT INDUSTRIES INC., A PA CORP. reassignment COLT INDUSTRIES INC., A PA CORP. MERGER (SEE DOCUMENT FOR DETAILS). EFFECTIVE ON 10/28/1986 PENNSYLVANIA Assignors: CENTRAL MOLONEY INC., A DE CORP., COLT INDUSTRIES OPERATING CORP., A DE CORP.
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
    • F15C1/00—Circuit elements having no moving parts
    • F15C1/08—Boundary-layer devices, e.g. wall-attachment amplifiers coanda effect
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/206—Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
    • Y10T137/218—Means to regulate or vary operation of device
    • Y10T137/2202—By movable element
    • Y10T137/2218—Means [e.g., valve] in control input

Definitions

  • Fluid from a pressurized source is injected into a reaction chamber at supersonic velocity. Either by means of offsetting one wall only of the chamber at the throat of the injection nozzle and/or by the creation of an artificial ambient pressure within and at one side of the chamber.
  • the fluid jet will be caused to normally attach to one wall of the chamber.
  • Monostable switching action is achieved by increasing the pressure within the recirculation region produced along the wall to which the supersonic jet normally attaches thereby reversing the transverse pressure unbalance across the jet.
  • the present invention relates to fluidics. More particularly, the present invention relates to fluid devices such as switches and relays which operate with supersonic flow and which are monostable in nature. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
  • Fluidics may be defined as the field relating to the control of apparatus by jets of high velocity fluid.
  • Prior art fluid relays comprise a casing defining a reaction chamber or operating region which is narrower at its entrance end than at its discharge end.
  • the casing is formed with an inlet port, through which a power or main stream of fluid is discharged into the narrow end of the reaction chamber, and will have an outlet passage or passages leading from the other or wide end of the reaction chamber.
  • the diverging walls of the reaction chamber at both sides of the inlet port were offset from the discharge end of the inlet port whereby the narrow end of the reaction chamber was wider than the inlet port.
  • One and usually two control ports the ports facing one another and having axes which are oriented transversely to the axis of the inlet port, are typically located closely adjacent to the narrow end of the reaction chamber.
  • the inlet and control ports are connectable to supplies of gas under pressure, the usual operating pressure being somewhere between 5 and 15 p.s.i.
  • the power stream By admitting fluid under pressure to the control port on the side of the chamber toward which the mam or power stream of fluid discharging from the inlet port is bent, the power stream can be caused to swing to the opposite wall of the reaction chamber so that it is then directed into the other outlet passage.
  • a comparatively small quantity of low pressure control fluid can thus control a jet powerful enough to perform control or propulsion functions when directed in the appropriate outlet passage.
  • the pressure in the power stream issuing from the inlet port of the prior art fluid relays is super-atmospheric and, because the pressure is super-atmospheric and also because of the tendency of the stream of fluid to adhere to one wall or the other of the reaction chamber, it has been necessary to form prior art fluid relays in such a manner that the stream issuing from the inlet port cannot contact either wall of the chamber immediately as it leaves the inlet port.
  • This design requirement is necessary in order to provide a space within which the control fluid may operate transversely against the stream issuing from the inlet port.
  • prior art fluid relays are formed in such a manner that the narrow end of the chamber is wider than thedischarge end of the port through which the power stream enters the reaction chamber. This is usually referred to as offsetting the control ports and the amount by which the control ports are offset is usually referred to as set back.
  • conventional prior art fluid relays operate mainly on simple mechanical principles whereby the pressure of the control fluid simply pushes the power stream of fluid issuing from the inlet port in a tranverse direction and forcibly detaches it from the wall of the chamber along which it was flowing and causes it to move by a form of snap action over to the other side of the chamber where the fluid attaches to the other wall.
  • Prior art fluid relays of the type briefly described above are incapable of providing output streams with suflicient energy to perform many control functions. Attempts have been made to enhance the power output of fluid relays by increasing the pressure of the fluid and particularly by increasing the pressure to such an extent that the fluid injected into the reaction chamber leaves the inlet port with supersonic velocity. While most prior art attempts to utilize supersonic flow have resulted in unstable devices, particularly when the downstream or back pressure against which the device operated was not constant, a stable and highly eflicient supersonic fluidic switch is described in copending application Ser. No. 786,684 filed by the same inventor on Dec. 24, 1968. The disclosure of copending application Ser. No. 786,684- is incorporated herein by reference. The apparatus disclosed in the said copending application is bistable in nature in that the power stream may be switched to either wall of the reaction chamber and will retain attached to the wall to which it has been directed until switching is again commanded.
  • the present invention overcomes the above-discussed and other disadvantages of the prior art by providing for the monostable operation of supersonic fiuidic switches.
  • Devices in accordance with the present invention are characterized by an inlet port which cooperates with the diverging walls of the reaction chamber to define a convergent-divergent nozzle.
  • the pressure at the source of fluid for the power stream is selected to be sufficiently high that the fluid expanding through the nozzle will attain supersonic velocity. Switching of the supersonic jet is achieved, in monostable operation, by reversing a transverse pressure unbalance created across the jet.
  • the reaction chamber is designed in such a manner as to produce a condition adjacent to the discharge end of the inlet nozzle whereby an oblique shock wave is generated; the shock wave serving to promote attachment of the supersonically flowing fluid to the wall from which the shock wave emanates.
  • boundary layer separation and reattachment will occur and a low pressure recirculation region or vortex will be created on the wall along which the supersonic fluid is flowing.
  • the pressure intermediate the separation and reattachment points of the power stream to the chamber wall may be increased to thereby reverse a transverse pressure unbalance across the stream and cause switching.
  • closing of the control port will result in the power stream immediately reattaching to the wall in which the control port is located.
  • the oblique shock wave is produced by offsetting a small distance the chamber wall which has the control port therein; the set back being at the throat of the convergent-divergent inlet nozzle.
  • the opposite wall of the chamber will exhibit the gradual change or flaring from the nozzle which is characteristic of the supersonic switches of copending application Ser. No. 786,684.
  • monostable operation and/or altitude compensation may be provided through the creation of a region of artificial ambient pressure within the fluidic switches.
  • This artificial ambient will be created adjacent to the opposte wall of the chamber from that along which it is desired to normally have the stream flow.
  • the artificial ambient is created by a combination of forward pressure feed from the power stream source and secondary injection. Creation of the artificial ambient provides a degree of immunity from the large ambient pressure fluctuations which may be imposed on the devices of the present invention when employed in environments such as missiles.
  • FIG. 1 is a cross-sectional, top view of a first embodi: ment of the present invention.
  • FIG. 2 is a cross-sectional, side view of a second embodiment of the present invention; the embodiment of FIG. 2 being depicted in the environment of a reaction engine control.
  • FIG. 1 a monostable fluidic switch in accordance with the present invention is shown.
  • the switch of FIG. 1 comprises a casing, indicated generally at 10, which is etched or machined to provide a reaction chamber 12.
  • Reaction chamber 12 is defined, in part, by diverging walls 14 and 1 6 and by-an'exit or discharge port 18.
  • the switch of the embodiment of FIG. 1 is also characterized by a convergent-divergent nozzle, the convergent portion of the nozzle being indi-- cated at 20, through which pressurized fluid from a source, not shown, is discharged into reaction chamber 12, the reaction chamber serving as the divergent portion of the inlet nozzle.
  • the pressure P at the upstream end of nozzle 20 is sufficient to impart supersonic velocity to the fluid expanded through nozzle 20 into chamber 12.
  • FIG. 1 is also characterized by a control port 22 in wall 16. Communication between control port 22 and the ambient atmosphere 'is via passage 23 formed in casing 10. A control valve 24 is disposed in passage 23 whereby port 22 may either be placed a the ambient pressure'P or isolated therefrom.
  • Wall 14 of reaction chamber 12 in accordance with the teachings of copending application 786,684, diverges from the exit end of nozzle 20 without any set back.
  • wall 16 of chamber 12 is oflset'by a small amount at section A-A as shown. The reason for theset back of wall 16 will become obvious from the description of the operation of the invention to follow.
  • the applied pressure P is of suflicient magnitude to cause sonic flow at the throat section AA of nozzle 20 against the ambient back pressure P Due to the sonic flow condition, fluid discharged from nozzle 20 will expand into the divergent reaction chamber completely filling the chamber to section BB and forming an oblique shock wave X emanating from the corner tiating the corner resulting from the set back of wall 16.
  • the control port 22 is positioned intermediate the points of separation and reattachment so as to be in communication with the recirculation region.
  • the pressure within the recir culation region is alsoless than the pressure P in chamber 12 caused by entrainment activity on the free surface of the jet; P being less than P due to entrainment.
  • the 7 pressure differential between P and the recirculation region pressure P will aid in holding the jet against wallv 16 until such time as switching is commanded.
  • control port 22 When it is desired to switch the jet from wall *16 to wall 14, control port 22 will be placed into communication with the ambient atmosphere, or other suitable pressurized source, by means of opening valve 24. Opening of the control port to the source of pressurized fluid disrupts the existing condition of stability by raising the pressure in the recirculation region from P to P and, since P is greater than P the power stream will be switched to wall 14 by reversal of the transverse pressure differential. When switched to wall '14, the power stream will attach thereto and a new recirculation region will be formed along wall 14. With valve 24 open, the openvortex in chamber 12 resulting from entrainment activity on the free surface of the jet, which vortex had previously produced the chamber pressure P will be disrupted.
  • valve 24 With valve 24 open and the jet switched to wall 14, the chamber pressure will become P where A' A" A- Reclosure of valve 24 will cause P to decrease toward P since the disruption of the open vortex, caused by fluid entering the chamber through control port 22, will be terminated. Accordingly, the jet will be caused to return to wall 16 due to the combined effects of transverse pressure unbalance and set back orientation. That is, closing of control valve 24 will reduce the pressure unbalance to the point where it is unable to overcome the transverse acceleration forces, the jet will return to wall 16 and the original transverse pressure unbalance P P will be reestablished.
  • the set back of wall 16 at section AA permits transverse acceleration of the power stream at its point of entry to reaction chamber 12 and thereby orients the velocity vector along wall 16 causing sufiicient bias to permit the above-described monostable operation.
  • the AP across the inlet nozzle and the back pressure P are critical design factors in that these parameters control the size of the recirculation region. If the recirculation region is too small, attachment of the jet to wall '16 may not be maintained.
  • FIG. 2 operates in essentially the same manner as that of the FIG. 1 embodiment.
  • the FIG. 2 embodiment is provided with a flow splitter 30 which divides the outlet port into a pair of channels 32 and 34.
  • a flow splitter 30 which divides the outlet port into a pair of channels 32 and 34.
  • the direction of the power stream through channel 32 will cause the power stream to impinge transversely upon the engine exhaust, at pressure P and thus will permit thrust vector control.
  • the direction of a fluid through outlet channel 34 will permit discharge or dumping into the ambient atmosphere and may provide a transverse stream of fluid for steering purposes.
  • thrust vector control is the stable control mode. It is, of course, to be understood that the device may be rendered inoperative by interrupting the communication between the source and nozzle 20 by means not shown.
  • conduit 36 is provided to feed pressure forward from the power stream source to a point along wall 14 opposite to control port 22. This forward pressure feed loop creates an artificial ambient which, in cooperation with the attachment vortex in the vicinity of the control port, will create a transverse pressure unbalance which will cause the power stream to remain attached to wall 16 unless control action is effected.
  • conduit 36 includes a stagnation region for converting fluid velocity to pressure.
  • conduit 38 extends between the upstream side of valve 24 and a region of pressure P With valve 24 in the open condition, communication is provided between the control port 22 and the engine exhaust, P being relatively constant and higher than either the artificial ambient or P Opening of valve 24 will, accordingly, unbalance the pressure differential across the power stream and cause switching of the power stream to wall 14 and channel 34. Reclosing of valve 24 will result in the power stream returning to wall 16 and channel 32. It is, of course, to be recognized that conduits 36 and 38 may be replaced by auxiliary sources of pressurized gas.
  • FIG. 2 operates into a differential back pressure (P and P Such operation, which has not previously been possible due to stability problems, is permitted by the creation of the artificial ambient.
  • a monostable fluidic device comprising: an operating region defined in part by a pair of diverging side walls; convergent nozzle means, said nozzle means communicating with the narrow end of said operating region and cooperating with said side walls to define a convergent-divergent nozzle for discharging a stream of fluid into said operating region at supersonic velocity; control means for causing a stream of fluid discharged into said operating region to normally flow along a first of said side walls, the supersonic velocity of the fluid resulting in separation and reattachment of the fluid stream to said first side wall, a low pressure recirculation region thereby being established between said points of separation and reattachment and a transverse pressure unbalance being thus created across the fluid stream in the vicinity of said recirculation region; a control port positioned in said first side wall between said points of separation and reattachment; and normally closed valve means for selectively supplying fluid at a pressure in excess of that established in said recirculation region to said control port, opening of said
  • valve means comprises:
  • valve the downstream side of said valve being in communication with said port; and means connecting the upstream side of said valve to a source of fluid.
  • control means comprises: i 7
  • conduit means providing communication between said second port and the upstream side of said nozzle means.
  • control means further comprises:
  • flow diverter means positioned at the wide end of said operating region, said diverter means cooperating with said side walls to define a pair of outlet ports from said operating region.
  • conduit having a first end connected to said valve and a second end in communication with the back pressure against which the device is operating.
  • conduit having a first end connected to said valve and a second end in communication with the back pressure against which the device is operating.
  • control means comprises:
  • control means comprises:
  • control means comprises:
  • control means further comprises:

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Toys (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Jet Pumps And Other Pumps (AREA)
US3606901D 1969-09-05 1969-09-05 Monostable fluidic switch Expired - Lifetime US3606901A (en)

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US85567269A 1969-09-05 1969-09-05

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US3606901A true US3606901A (en) 1971-09-21

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US3606901D Expired - Lifetime US3606901A (en) 1969-09-05 1969-09-05 Monostable fluidic switch

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US (1) US3606901A (enrdf_load_stackoverflow)
CA (1) CA922232A (enrdf_load_stackoverflow)
DE (1) DE2043961A1 (enrdf_load_stackoverflow)
GB (1) GB1288845A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4413795A (en) * 1980-09-05 1983-11-08 The Garrett Corporation Fluidic thruster control and method
US4537371A (en) * 1982-08-30 1985-08-27 Ltv Aerospace And Defense Company Small caliber guided projectile

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2355543A (en) * 1999-10-20 2001-04-25 Univ Sheffield Fluidic flow control and fluidic device
CN113883133B (zh) * 2021-09-18 2024-07-12 天津大学 一种基于附壁效应的单稳态输出反馈式射流振荡器

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4413795A (en) * 1980-09-05 1983-11-08 The Garrett Corporation Fluidic thruster control and method
US4537371A (en) * 1982-08-30 1985-08-27 Ltv Aerospace And Defense Company Small caliber guided projectile

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Publication number Publication date
CA922232A (en) 1973-03-06
GB1288845A (enrdf_load_stackoverflow) 1972-09-13
DE2043961A1 (de) 1971-03-11

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Legal Events

Date Code Title Description
AS Assignment

Owner name: COLT INDUSTRIES INC., A PA CORP.

Free format text: MERGER;ASSIGNORS:COLT INDUSTRIES OPERATING CORP., A DE CORP.;CENTRAL MOLONEY INC., A DE CORP.;REEL/FRAME:004747/0300

Effective date: 19861028

Owner name: COLT INDUSTRIES OPERATING CORPORATION, A CORP. OF

Free format text: MERGER;ASSIGNORS:LEWIS ENGINEERING COMPANY, THE, A CT CORP.;CHANDLER EVANS INC., A DE CORP.;HOLLEY BOWLING GREEN INC., A DE CORP.;REEL/FRAME:004747/0285

Effective date: 19870706