DE2043961A1 - Monostable fluid switch - Google Patents

Description

DR. BERG DIPL.-ING. STAPF PATENT Attorneys £ U 4 O · \ 3 O I

8 MUNICH 2, HIUBLESTRASSE 2O

Df. Berg Dipl.-Ing. Stapf, 8 Munich 2, HllblestraBe 20

Your mark Your letter Our mark

Attorney's files Mr. 19 931

Raymond V. Thompson Sinsbury Connecticut / USA

Monostable positive switch

DCurn

4. ββΡ. 1970

The invention relates to fluid devices or fluid mechanical devices, for example switches and relays, which operate with an overhead flow and are monostable .

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The rapid development in certain areas of technology, such as ballistic projectiles, where the mechanism for controlling the punctures or movements of the device must react quickly, must be highly reliable and light in weight, drew attention heavily to the technology of the Fluid control elements or flow mechanisms, control baits Amplifier devices, which in the following for the sake of brevity are all referred to as fluid control elements. The field of fluid control elements can be defined as a technique that focuses on the regulation and / or the Control of devices and facilities by jetting a fluid (below fluid we mean gaseous or drip liquids, but preferably gaseous liquids are understood) with high flow velocity relates.

One of the most important devices in the field of fluid control elements is the fluid relay or switch. Known fluid relays include a housing that forms a reaction chamber or work area, > which is narrower at its inlet end than at its outlet end. The housing has an integrally molded inlet passage through which a force or main stream of the fluid is entered into the narrow end of the reaction chamber will. Furthermore, the housing bit is an outlet port

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occurs or several such passages are provided, which lead away from the other or wide end of the reaction chamber. In the known fluid relays, the diverging walls of the reaction chamber were on both sides of the inlet passage offset from the outlet side of the inlet passage, the narrow end of the reaction chamber wider than the inlet passage was. One tax pass, usually two tax passes, which face each other and have axes oriented transversely to the axis of the inlet passage usually close to the narrow end of the reaction chamber. The inlet and control passages are with gas A. Feed lines with pressurized gas can be connected, the normal operating pressure between about 0.35 and 1> 1 kp / cm lies.

When the known fluid relay is operated, a moves low velocity fluid jet emanating from the inlet passage into the diverging reaction chamber. As a result of irregularities in the flow and an asymmetry in the shape of the chamber, the Fluid jet deflected to one side or the other before flowing into an outlet passage closer to this side. As a result of the subsonic speed of the fluid, there is no significant expansion or expansion of the force jet when the beam enters the reaction chamber

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occurs. By supplying fluid under pressure to the control passage on the side of the chamber against which the main or force jet of the fluid after flowing in is deflected by the inlet passage, the jet of force may be directed to the opposite wall of the reaction chamber be pivoted so that it then passes into the other outlet passage is directed. A relatively small amount of low pressure control fluid can in this way Steer the beam with enough force to perform steering or propulsion functions when aligning takes place in the corresponding outlet passage.

The prior art low-pressure relays briefly described above are based on the Coanda effect. This can briefly be viewed as the endeavor of a fluid in motion to flow along a surface and to follow the outline of a surface even as it curves away from the direction of flow of the fluid is. In utilizing the Coanda effect, a fluid of relatively low pressure had to be used, whereby the speed of the jet of force emanating from the inlet passage is low and below the sound limit. In this way, the pressure in the force flow, which emanates from the inlet passage in the known fluid relays, over-atmospheric. Because the pressure is superatmospheric and the fluid flow has a tendency to at one

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or other wall of the reaction chamber to adhere the known relays are designed so that the outgoing from the inlet passage beam immediately after leaving the inlet passage is unable to touch any wall of the chamber.

This design is necessary in order to create a space within which the control fluid can act in the transverse direction against the jet emanating from the inlet passage. In order to create the reaction space in accordance with the above explanations, in known fluid relays the narrow end of the chamber is wider than the outlet end of the passage through which the jet of force enters the reaction chamber. This is commonly referred to as the staging of control steps; the extent of the offset of the control throughputs is usually called "setback ¹¹ (in American parlance referred to as" set back "). Overall, the known positive relays are mainly based on simple mechanical laws, whereby the force flow of the fluid emerging from the inlet passage in the transverse direction with the pressure of the Control fluids are acted upon and detached under force from the chamber wall along whose fluid flowed, the fluid being caused to move over to the other side of the chamber and on by a kind of snap action

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the other wall.

Known positive relays in accordance with the above explanations are unable to create output beams of sufficient energy to fulfill many control functions. Attempts have been made to increase the power output of fluid relay by the fluid pressure was increased, ^w ert particularly to such that the current injected into the reaction chamber fluid leaves the inlet passage at supersonic speed. While most of the prior art attempts to use supersonic flow have resulted in unstable devices, particularly when the downstream pressure or back pressure against which the device was operating was not constant, a stable and very effective supersonic fluid switch is not yet known in US made pending British patent application 58834/67. The device contained in this proposal is bistable insofar as the flow of force can be switched to any wall of the rectification chamber and remains applied to this wall against which it was directed until another switching command comes.

Although the aforementioned suggestion, which does not belong to the state of the art, is useful, there are many cases of application,

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which require the high energy Output fluid jet at supersonic speed after the cessation of a control action automatically to a selected flow mode returns. For example, it is in a thrust vector control for a rocket motor favorable if the control functions are reduced and a single valve can be used to initiate and terminate the control action exerted by the output fluid the vector control current and the engine exhaust jet is achieved. Accordingly, there is a need for fluid relays, which are monostable in operation and have a known output power using a supersonic flow hand over.

The invention avoids the disadvantages mentioned above and the other disadvantages of known devices in that they have monostable operation in supersonic fluid switches permitted. Devices according to the invention are characterized by an inlet passage, which with the divergent walls of the reaction chamber cooperates to form a convergent / divergent nozzle. The pressure at the fluid source for the power jet becomes sufficiently high chosen so that the fluid expanding through the nozzle reaches supersonic speed. The switching of the supersonic jet is achieved in monostable operation by a transverse pressure misalignment that is transverse to the Ray is created, is reversed.

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According to a first embodiment of the invention is the reaction chamber formed so that a state near the outlet end of the inlet nozzle is created in which one oblique shock wave is generated. The shock wave serves to address the concern of the flowing at supersonic speed To promote fluids to the wall from which the shock wave originates. As a result of the supersonic flow, a Boundary layer separation as well as a re-installation, with a low-pressure back circulation area or a vortex the wall, along which the supersonic fluid flows.

A control effect can be achieved by installing a control passage between the points of separation and reinvestment. In this ^w ay, by a valve in series with the control passage of the pressure between the points of separation and re-installation of the ^ raftstrahls be increased to the chamber in order to achieve in this way a passage extending in the transverse direction pressure incorrect equalization across the flow and in this way To cause switching operation. Because of the speed gradient, which leads to the generation of the above-mentioned oblique shock wave, however, closing the control passage leads to an immediate reapplication of the force jet on the wall in which the control passage is located.

According to the first embodiment of the invention, the

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oblique shock wave generated by the chamber wall, which in it receives the control passage, is offset by a small distance, the offset on the neck the converging / differentiating inlet nozzle takes place »The opposite wall of the chamber shows a gradual Modification or expansion of the nozzle, which does not belong to the state of the art for supersonic switches Proposal made in accordance with the aforementioned British patent application is characteristic.

According to the invention a mono-stable operation and / or a height compensation may be provided by a region artificial ^u mgebungsdruckes provided within the fluid switch. This artificial ambient pressure is created adjacent to that chamber wall which is opposite to the other wall which is normally intended to guide the flow. The artificial ambient pressure is created by a combination of a forward pressure supply from the power jet source and a secondary injection. The artificial ambient pressure results in the fact that rare, large fluctuations in the ambient pressure cannot be influenced, which fluctuations can occur in the devices according to the invention when the invention is applied under ambient conditions such as those that exist for projectiles.

According to the invention, a mono-stable fluid switch unit is

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direction created, which has the following facilities: A working chamber, which is partly by a pair of diverging Side walls is formed, element nozzles which interact with the narrow end of the operating area, around a convergent / divergent nozzle for emitting a pluid jet into the working chamber at supersonic speed to create controls for acting on the fluid jet in the sense of a flow along the first side wall of a pair of side walls, whereby due to the supersonic velocity of the fluid a separation of the and re-application of the fluid jet to the sidewall takes place, a low pressure recirculation area between the points of separation and re-installation and a transverse pressure equalization is ensured in the Fluid jet created near the recirculation area and components for reversing the pressure balance across the beam around it along the second opposite side wall of the working chamber to flow, with a shutdown of the pressure balance reversal element allows the beam to return to the first side wall.

The invention is detailed below with reference to the drawing explained:

Pigο 1 shows a first embodiment of an inventive Establishment on average.

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Figo 2, a second embodiment shows a inventions ^■: <lung proper device in section and when used in conjunction with a controller for a recoil engine.

The monostable fluid switch according to ^£ ig. 1 includes a housing 10 which is etched or machined to form a reaction chamber 12. The reaction chamber 12 is limited in part by diverging walls 14 »16" and has an outlet or outlet passage 18. The switch according to ^{FIG. 1} IgV 1 "is also provided with a convergent / divergent nozzle through its convergent. Part 20, a bridged fluid supplied by a fluid source (not shown) flows into the reaction chamber 12 which serves as the diverging part of the inlet nozzle. The pressure Pg at the upstream end of the nozzle 20 is sufficient to cause the fluid exiting through the nozzle 20 into the chamber 12 to assume supersonic speed.

A control passage 22 is attached to a wall 16. The control passage 22 is with the surrounding atmosphere connected via a passage 23 which is in the housing 10 is formed. A control valve 24 is in the passage 23 arranged, the passage 22 either at the ambient pressure P ^ or can be kept separate from it.

The wall 14 of the reaction chamber 12 diverges accordingly

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the aforementioned, unpublished British patent application 58 834/67 of the exit end of the Nozzle 20 without any setback. However, the wall of the chamber 12 is a small amount at the cross-section A-A as shown in the drawing.

The reason for the deposition of the wall 16 is explained in more detail below.

As mentioned above, the applied pressure P _{g is} sufficiently great to bring about a sound flow at the mouth AA of the nozzle 20 against the ambient back pressure P. As a result of the state of the sonic flow, the fluid that has emerged from the nozzle 20 expands into the diverging reaction chamber, the chamber being completely filled up to the section BB and an oblique shock wave X being formed which emanates from the corner of the wall 16.

The shock wave X results from the sudden change in the direction of flow, which the expanding fluid when negotiating the corner as a result of the deposition of the wall 16 is imposed. As a result of the lateral acceleration of the fluid expanding through the nozzle 20, this transverse acceleration resulting from the settling of the wall 16, the flow separates from wall 14 at section B-B as shown. The fixed and owing to

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the shock wave generated by the separation of the flow from the wall 14 is indicated at Y.

Because of the detachment of the beam from the wall 14 and because of the Coanda effect, the force beam is applied to the wall and flows along it. Because of the Übersdhallström-. However, as a result of the back pressure P. a separation of the fluid jet from the wall 16 occurs at a section CG, this separation causing another locally fixed shock wave Z. As a result of the turbulence that occurs between the wall 16 and the jet of force, the jet rests against the wall 16 again at a section DD, including a recirculation or vortex area of the pressure P _B, which is adjusted on the average. The pressure P _B is less than P ^. As previously mentioned, the control passage 22 lies between the points of separation and reinstallation to provide communication with the recirculation area. Furthermore, the pressure within the recirculation area is also lower than the pressure P 'in the chamber which is caused by the entrainment effect on the free surface of the jet. The value P / is lower than the value due to the entrainment effect. The pressure differential between the value P * ¹ and the pressure P «of the return circulation area contributes to the jet on the wall

hold until a switch is commanded.

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When the jet is to be switched from wall 16 to wall 14, control passage 22 is brought into communication with the surrounding atmosphere or other suitable pressure source by opening valve 24. The opening of the control passage to the pressurized fluid source interrupts the present state of stability in that the pressure in the recirculation region is raised from the value P _B to the value P *; since P. is greater than P., the power jet of the wind 14 is switched by reversing the transverse pressure differential. When a switchover to the wall 14 takes place, the force beam is applied to it and a new recirculation area is formed along the wall 14. When the valve is open, the open vortex in the chamber 12, which is caused by the entrainment effect on the free surface of the jet, (this vortex was previously generated by the chamber pressure P. ') is interrupted. Accordingly, when the valve 24 is open and the jet is switched to the wall 14, the chamber pressure assumes a value P. ", where

Closing the valve 24 again causes the pressure to drop from the value P. "" to the value P. ¹ , since the interruption of the open vortex created by the fluid entering the chamber through the control passage 22 is terminated the ray causes, as a result

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the combined effects of the transverse pressure mismatching as well as the deposition to return to the wall 16. This means that when the control valve 24 is closed, the Pressure mismatch is reduced to the point where it is no longer able to handle the lateral acceleration forces with the jet returning to wall 16 and the original transverse pressure misbalance P. "~ 7 P-g is restored.

Overall, accordingly, when the fluid switch according to FIG. 1 is operated, the wall 16 can be deposited on the cross section A-A the transverse acceleration of the force jet at this entry point to the reaction chamber 12 and aligns the speed along the wall 16, which creates a sufficient pretensioning effect, to ensure the monostable operation explained above. The pressure difference ρ across the inlet nozzle as well as the back pressure P »are critical design factors insofar as these parameters determine the dimensions of the back circulation area is too small, an accumulation of the jet on the wall 16 cannot be maintained.

The embodiment of FIG. 2 operates essentially in the same way as that of Fig. 1. However, a flow divider 30 is provided which passes the outlet passage divided into a pair of channels 32,34. Taking into account

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Consideration of the environmental conditions at an engine causes the direction of the power flow through the channel 32, that the force jet at a pressure P-g transversely to the engine gas jet hits and thus enables a thrust vector control. The direction of a flowing through the outlet passage 34 Fluids enables an outflow or an exit into the surrounding atmosphere and can create a cross-flow of fluid form for control purposes. When viewed in terms of a monostable operation, the thrust control is the stable type of control, - ^ s is possible, the establishment ineffective to keep by all connection between the source and the nozzle 20 interrupted by (not shown) components will.

As in the case of the exemplary embodiment according to i'ig. 1 will Gas expands through the nozzle 20, which brings about a separation and reattachment of the boundary layer on the wall 16, provided that valve 24 is initially closed. Since the ambient pressure P. ', Against which the jet of force acts, changes with the height, components in the form of a line 36 are provided to pressure in front of the power jet source to a point on the wall 14 opposite the control passage 22 to deliver. This forward pressure supply circuit results in an artificial ambient pressure, which with the contact vortex adjacent to the control passage a · »lateral pressure imbalance creates a

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Remaining of the force flow on the wall 16 causes unless there is a tax effect. The line 36 closes a standstill area for converting the Fluid velocity in pressure e, in.

the ambient pressure P ^ can be almost the same as that of the vacuum, it would not be sufficient to bring the control passage 22 via the valve 24 into communication with the surrounding atmosphere. Accordingly, a conduit 38 extends between the upstream side of the valve and a pressure area P ™. When the valve 24 is in the open position, there is a connection between the control passage 22 and the engine gas jet, the value Ρ, * · being relatively constant and higher than either the artificial ambient pressure or the value P ». An opening of the valve 24 calls accordingly a Pehlausgleieh the pressure differential across the flow of force produced and causes a switching of the ^ raftstrahls to the Wan 14 and the channel 34. A re-closing of the valve 24 results in a return of the power beam to the wall 16 and the channel 32. Accordingly, the lines 36, 38 by means of auxiliary sources of pressure are of the grass to be replaced.

A satisfactory operation of the positive switch according to -Pig. 2 can also be achieved without the separation of the wall 16

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will. However, while the application of the beam to the wall 16 is maintained without any transverse acceleration solely as a result of the transverse pressure mismatch between the artificial ambient pressure and the recirculation area pressure, it is favorable to use the one used Gas flow to create the artificial ambient pressure to be reduced by a certain deposition is provided. In this way, the switch design usually requires flow rate balancing through the line 36 opposite the offset of the wall 16, in order to ensure optimum operation with minimal gas consumption to achieve.

In the fluid switch of Fig. 2, operation in a differential back pressure (Bg and P.) is brought about. Such a Operation, which was previously not possible due to stability problems, is created by creating the artificial Ambient pressure allows.

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Claims (8)

2 o / t 3 9 6 1 Patent claims: Monostable fluid holder device, marked through a working chamber (reaction chamber 12), which is partly formed by a pair of diverging side walls (14, 16) is formed, nozzle elements (20), which with the narrow end of the operating range cooperate to form a convergent / divergent nozzle for dispensing a jet of fluid to create control elements (control valve 24) to act in the working chamber at supersonic speed on the fluid jet in the sense of a flow along the first side wall (16) of a pair of side walls, whereby, as a result of the supersonic velocity of the fluid, a separation from and re-installation of the Fluid jet takes place on the side wall, a low pressure recirculation area built between the points of separation and reinstallation as well as a transverse direction Pressure imbalance can be created in the fluid jet in the vicinity of the re-circulation area and components (Passage 23, grass valve 24) to reverse the pressure imbalance across the jet around it lengthways the second opposite side wall (14) of the working chamber to flow »with a shutdown of the pressure imbalance reversing element causes the jet to return to the first side wall. - 21 10 981 1/15Λ7 2U / .3961 2ο 2. Device according to claim 1, characterized in that the control element is a deposition of the first side wall (16) at the mouth of the converging / diverging nozzle (20), the deposition creating a velocity gradient in the fluid passing through the nozzle expands, which is secured so that the fluid is applied to the first (16) of the side walls. 3. Device according to one of claims 1 or 2, characterized in that the pressure misalignment reversal element a control passage (22) in the first side wall (16) between the points of separation (section C-C) and Reattachment (section D-D) comprises and that a valve (24) for the optional supply of fluid to the control passage is provided at a pressure above that which is built up in the recirculation area. 4. Device according to claim 3, characterized in that the upstream side of the valve (24) with a Fluid source is connected. 5. Device according to claim 3, characterized in that the upstream side of the valve (24) is in connection with the back pressure against which the device is working. - 22 - 1 0 9 8 1 1/1 F / 7 6. Device according to one of claims 1 to 5, characterized in that that the control element components (line 36) to create an artificial ambient atmospheric pressure within the working chamber (reaction chamber 12) next to the second wall (14) opposite to the side wall (16), along which the fluid flow initially circulates. 7. Switch according to claim 6, characterized in that the component for creating an artificial ambient atmospheric pressure a second passage (line 36) in the second wall (14) upstream of the recirculation area and that a line for establishing a connection between the second passage and the upstream wärtigen side of the nozzle (20) is provided. 8. Device according to one of claims 1 to 7, characterized by a flow diverter (flow divider 30) at the wide end of the working chamber, which is connected to the Side walls (14 »16) cooperates and forms a pair of outlet passages (channels 32,34) leading from the Open the working chamber (12). 109811/1547 Blank page