US3538934A - Vortex amplifier - Google Patents

Description

United States Patent [721 Inventors Louis R. Erwin [56] References Cited Livonia; UNITED STATES PATENTS 2 l A I N 52%;;- Mum, Michigan 3,198,214 8/1965 Lorenz 137181.5X Se 13 1968 3,290,947 12/1966 Reilly 137/81.5x P 3,343,790 9/1967 Bowles l37/8l.5X Patented NW1", 3 373 759 3/1968 Ad 137/81 5 73] Asslgnee The Bendix Corporation ams l a me 3,431,930 3/1969 Bowles 137/81.5 3,442,280 5/1969 Boothe 137/81.5

Primary Examinerwilliam R. Cline AttorneyPlante, l-lartz, Smith & Thompson ABSTRACT: A laminated vortex amplifier in which the vortex chamber is constructed to reduce the unstable flow conditions rawmg that occur at an input control pressure near the value required [52 US. Cl 137/8L5 to achieve cutoff of supply flow. in the disclosed embodiment [51] Int. Fl5c 1/16 this is accomplished by providing an interruption in the form [50] Field of Search 137/8 1 .5 of a slot in one end wall of the vortex chamber.

Patented Nov 10, 1970 3,533,934

INV'E NTORS LOUIS" R. ERWIN ROGER H. Mc FALL ATTORNEY VORTEX AMPLIFIER The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).

BACKGROUND OF THE INVENTION All vortex pressure amplifiers have inherent positive and negative internal l'eedbacks. When the inherent positive feed back is sufficiently large, the device tends to be unstable and therefore there exists a range of possible values of the pressure output signal which cannot be obtained as single value functions of input control pressure. This condition exists at an input control pressure near the value required to achieve cutoff of supply flow.

SUMMARY OF THE INVENTION It has been hypothesized that the unstable conditions which exist at an input control pressure near the value required to achieve cutoff of supply flow result from the boundary layer of swirling fluid first attaching and then breaking loose from the outer circumferential wall of the vortex chamber, thereby causing fluctuations in the pressure output signal for single value functions of the input control pressure. In the presentinvention, stabilization at this condition is obtained by inducing losses corresponding to negative feedback in the vortex chamber. The loss is introduced into the vortex chamber with the amount of loss increasing as the vortex chamber flow becomes more tangential and less radial. This is accomplished by forming an interruption in the form of a slot in one end wall of the vortex chamber. The interruption provided in the end wall prevents the fluid that is swirling in the vortex chamber from having a boundary layer which attaches to the outer wall. Thus, the condition which is believed to exist where the boundary layer first attaches and then breaks loose from the circumferentialwall is eliminated.

According to one form of' the present invention, a vortex fluid amplifier is provided comprising a body defining a cylindrical vortex chamber, an inlet passageway for supply fluid, an inlet passageway for control fluid extending substantially tangentially of said chamber and an exit passageway extending substantially axially from said chamber, and means are provided in the vortex chamber for breaking the boundary layer of swirling fluid from the circumferential wall of the chamber. In a preferred embodiment, the body of the amplifier is constructed from laminae, one of which is positioned on the exit wall of the vortex chamber, and this wall has an innermost lamina with an elongated opening cut therein which has a dimension so that the opposite ends of the opening extend at least as far as to the circumferential wall of the chamber. This interruption in the end wall affects the flow pattern. of the fluid in the vortex chamber to eliminate the unstable condition which otherwise would exist when the input control is near the value to achieve cutoff of the supply flow. While it is not known for certain what the precise flow pattern within a conventional vortex chamber is, it is known that there is a certain amount of internal recirculation with flow going radially outward in the center of the chamber length and radially inward along the end walls, in addition to a general rotation. It is believed that the interruption in the end wall affects this circulation in such a way so that the undesirable unstable condition discussed above is eliminated.

It is an object of this invention, therefore, to provide an improved vortex amplifier which is characterized by its stable operation.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a transverse sectional view of the vortex amplifier embodying the present invention; and

FIG. 2 is a sectional view taken on the lines 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of constructionnnd arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring now to the drawings, the vortex amplifier 10, embodying the present invention, will be described in greater detail. The vortex amplifier 10 consists of a laminated body 12 having a plurality of flat laminae 14-30, inclusive, which are positioned in surface-to-surface engagement and secured together to constitute the integral body 12. Prior to assembly, the laminae have been cut so that when assembled, they define an inlet passageway 32 for supply fluid, a pair of inlet passageways 34 for control fluid, an annular passageway 35 around the button or lamina 18 and radially inside of laminae 15, 16, a cylindrical vortex chamber 36, and an exit passageway 38 located substantially axially with respect to the vortex chamber 36. It will be noted, with particular reference to FIG. 2, that the inlet passageways 34 for control fluid are arranged substantially tangentially of the vortex chamber 36.

The wall which defines theexit end of the vortex chamber 36 comprises the laminae 20 and 22. The laminae 22 are similarly formed with a central opening to define the exit passageway 38, and the lamina 20 has an enlarged opening 40 therein which is elongated in shape and has its longitudinal axis perpendicular to the tangential inlet passageways 34. Also, the opening 40 along its longitudinal axis has a dimension which is at least as great as the diameter of the vortex chamber 36. This interruption or opening 40 in the end wall of the vortex chamber 36 functions to increase progressively the losses in the vortex chamber as the swirling fluid flow in the vortex chamber progressively becomes more tangential. It is discovered that the slot 40 functions when the input control pressure is near or at a maximum to create losses adjacent to the circumferential wall so that the boundary layer is prevented from attaching to the circumferential wall, thus avoiding the unstable condition which otherwise occurs when the tangential flow is near or at a maximum in the vortex chamber.

In the operation of the vortex amplifier 10, supply fluid is supplied through the inlet passageway 32 in the direction of the indicator arrow and control fluid is supplied through the tangential inlet passageways 34 so that fluid will issue from the exit passageway 38 in a cone-shaped configuration, with the magnitude of divergence of the fluid in the cone being determined by the magnitude of the pressure of the inlet control fluid introduced through passageways 34.

As shown in FIG. I, a vent passageway 44 is provided below the exit passageway 38, and the lamina 26 is provided with a pickoff orifice 46 for receiving portions or all of the fluid from the exit orifice 38. The fluids which pass through the pickoff orifice 46 are then discharged through the discharge passageway 48 'in the conventional manner.

The present invention has utility with vortex amplifiers having internal as well as external pickoff orifices, and any suita ble arrangement for vent passageways may be employed.

We claim:

1. A vortex'fluid amplifier comprising a body defining a cylindrical vortex chamber, an inlet passageway for supply fluid, an inlet passageway for control fluid extending substantially tangentially of said chamber and an exit passageway extending substantially axially from said chamber, and means in said vortex chamber disposed adjacent the circumferential wall of said chamber for breaking the boundary layer of swirling fluid from the circumferential wall of said chamber.

2. A vortex fluid amplifier as claimed in claim I, wherein said means comprises an interruption in one end surface of said vortex chamber, said interruption extending into proximity to said circumferential wall.

3. A vortex fluid amplifier as claimed in claim 1, wherein said-means comprises a slot in one end surface of said vortex chamber.

4. A vortex fluid amplifier as claimed in claim 1, wherein said body is formed of a plurality of laminae arranged normal to the axis of said vortex chamber with openings therein to define said passageways and said chamber, and said means includes one of said laminae having a hole cut therein of a dimension and in a location to provide a slot in the end surface of the vortex chamber, said slot extending into proximity to said circumferential wall.

5. A vortex fluid amplifier as claimed in claim 4, wherein said one lamina is positioned at the exit end of said vortex chamber.

6. A vortex fluid amplifier as claimed in claim 5, wherein the hole in said one lamina is elongated and has a major axis at least as long as the diameter of said vortex chamber.

7. A vortex fluid amplifier as claimed in claim 6, wherein said body defines two inlet passageways for control fluid, said two inlet passageways being normal to said major axis of the elongated hole.

Images