US3846039A

US3846039A - Axial flow compressor

Info

Publication number: US3846039A
Application number: US00408476A
Authority: US
Inventors: E Stalker
Original assignee: Stalker Corp
Current assignee: CHROMALLOY COMPRESSOR TECHNOLOGIES Corp C/O CHROMALLOY GAS TURBINE CORPORATION; Stalker Corp
Priority date: 1973-10-23
Filing date: 1973-10-23
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05

Abstract

A supersonic axial flow compressor is formed with an annular compartment downstream of the rotor. The compartment is provided with axially extending dividers or partitions which divide the compartment into sub-chambers. The walls of the partitions form curved surfaces which are inclined to the direction of flow from the rotor to induce a succession of shock waves for increasing the static pressure. A collector is axially positioned with respect to the compartment and shares with the compartment a common dividing wall within which are formed a plurality of inclined passages which receive the flow and direct it into the collector. The passages are inclined both to the radius and the axis to accommodate the high speed flow without generating shock waves, and are formed with throats which converge and diverge in the direction of flow.

Description

United States Patent 11 1 Stalker 1 5] Nov. 5, i974 [52] U.S. Cl 415/206, 415/209, 415/210 [51] Int. Cl. F01d 9/00, F03b 3/16 {58] Field of Search 415/181, 206, 209, 210,

[56] References Cited UNITED STATES PATENTS 2/1953 Wosika 415/210 3,285,567 11/1966 Richardson.. 3.652.184 3/1972 Conrad 415/209 FOREIGN PATENTS OR APPLICATIONS 991,675 4/1902 France 415/209 Primary Examiner-Carlton R. Croylc Assistant Examiner-Louis J. Casarcgola Attorney, Agent, or Firm-Biebel, French & Bugg [57] ABSTRACT A supersonic axial flow compressor is formed with an annular compartment downstream of the rotor. The compartment is provided with axially extending dividers or partitions which divide the compartment into sub-chambers. The walls of the partitions form curved surfaces which are inclined to the direction of flow from the rotor to induce a succession of shock waves for increasing the static pressure. A collector is axially positioned with respect to the compartment and shares with the compartment a common dividing wall within which are formed a plurality of inclined passages which receive the flow and direct it into the collector. The passages are inclined both to the radius and the axis to accommodate the high speed flow without generating shock waves, and are formed with throats which converge and diverge in the direction of flow.

7'Claims, 5 Drawing Figures PATENTEDNUV 5 m4 FIG-4 I FIG AXIAL FLOW COMPRESSOR BACKGROUND OF THE INVENTION This invention relates to elastic fluid compressors and more particularly axial flow compressors in which the flow of fluid from the compressor rotor is supersonic. Supersonic axial flow compressors can produce .high compression ratios but they often present problems in diffusing the flow to increase thestatic pressure, and problems in turning the flow to a desired direction.

SUMMARY OF THE INVENTION In the present invention, means are disclosed for increasing the static pressure in an axial flow compressor by first passing the flow from the compressor blades along'a curved surface. It is known that supersonic flow of about Mach 1.7 when turned by a 12 wedge will have a shock wave that drops the Mach number down to about 0.92. This invention utilizes curved surfaces to create successive inclined shock waves for effectively increasing the static pressure, in combination with inclined inlets or passages leading from a compartment defined by curved walls, into a collector.

The fiow from the rotor of an axial flow compressor is directed mainly in the peripheral direction. This flow is reduced in velocity by passing the supersonic flow along curved surfaces which take the form of axially extending walls or dividers defining generally annular sub-compartments. A common wall separates the subcompartments from a collector, and passages or collector inlets are formed in this wall to direct the flow into the collector. The inlets are inclined both to the radius and to the axis and direct the flow substantially along the surface of the wall in the collector.

It is an accordingly important object of this invention to provide an axial flow compressor in which curved wall means are employed to reduce the velocity of the supersonic flow.

A furtherobject of this invention is the provision of an axial flow compressor in which the output of the compressor is received within a compartment defined by a radial series. of axially extending curved wall means. and in which a collector receives the flow from the compartment through inclined inlet passages.

Another important object of the invention is the provision of a collector compartment in an axial flow compressor which has at least one axially extending divider which is curved in the direction of fluid flow, to induce a series of shock waves. The divider also reduces the intensity and magnitude of turbulence which would otherwise arise from the fact that there are different fluid velocities in the portions ofthe flow from different radial portions of the compressor blades.

These and other objects and advantages of the inven-' tion will be apparent from the following description, the accompanying drawings, and the appended claims.

.BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 discloses a compressor according to this invention, in axial section;

FIG. 2 shows a fragmentary development of the rotor;

FIG. 3 is a plan view ofthe compressor of FIG. 1 with the case being partially broken away;

FIG. 4 is a section on line 4-4 in FIG. 3; and

FIG. 5 is an enlarged development of a fragment of I the collector particularly to show the passages leading into the collector.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the figures in the drawings, a supersonic axial flow compressor constructed according to the teachings of this invention is shown in'and as including a rotor 20. The rotor 20 has blades 22 mounted on a hub 24 which is, in turn, mounted on a shaft 26 and supported for rotation on bearings 28 in a case 29. Fluid enters at the entrance 30 and flows between the blades 22 in the direction of the arrows 33 and into an annular compartment 34.

The compartment 34 is subdivided into generally concentric sub-compartments including an inner subcompartment 35, a middle sub-compartment 36,-and an outer sub-compartment 37, by a pair of wall means or

divider

40 and 41 and an inside wall 42. The

dividers

40 and 41 are extended generally axially in the direction of the rotor 20 and from the sub-compartment which receive flow.from corresponding axial regions of the blades 22. The divider surfaces together with the walls of the case 29 present curved surfaces to the flow from the compressor blades 22.

As seen in FIG. 2, the flow from the blades 22 has a large peripheral component of velocity and a relatively smaller axial velocity component. Since the

dividers

40 and 41 are curved in the direction of flow they precipitate a succession of inclined shock waves which reduce the supersonic flow velocity. While a pair of

dividers

40 and 41 is disclosed forming three sub-compartments, it is within the scope of the invention to use more or less said dividers or to employ a single spirally formed divider to assure the benefits of this invention.

The fluid is extracted from the compartment 34 into a collector by preferably inclined inlets 43 which are formed in the rear wall 44 of the compartment 34. The rear wall 44 is also the front wall of the collector 50. The inlets 43, as shown in FIGS. 4 and 5, are inclined both at an angle to the radius and at an angle to the axis to accommodate the high speed flow without generating shock waves. The inlets 43 may extend entirely across the compartment 34 or may extend only across one of the sub-compartments as shown by the inlets 43A extending across the outermost compartment 37 in FIG. 4. The collector 50 has one or more conduits leading out of the collector for the discharge of flow therefrom.

The inlets 43 direct the flow from the compartment 34 substantially along the wall 44 within the collector 50. The inlets thus define passages which may be formed with throats as defined by the wall 44 and inwardly extending fingers 62 which converge somefluid velocities existing in the portions of the flow from.

corresponding radial portions of the blades 22.

It is preferred that the slots defined in the inlets 43 be placed as close together as 12 of are. As this may not be practical this spacing may be greater. However, the spacing of the inlets leading to the collector from the outer sub-compartments 37 may be greater in number, as shown by the inlets 43A of HO. 4.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. In an axial flow compressor having a bladed rotor, the improvement comprising an annular compartment positioned in downstream relation to the rotor and adapted to receive the flow from the compressor blades, said compartment being defined by a back wall and axial wall means extending from said back wall toward the compressor blades dividing said compartment effectively into a plurality of radially spaced subcompartments, a collector positioned, axially downstream from said compartment, said compartment back wall forming a partition between said compartment and said collector, and means in said back wall defining a plurality of angularaly spaced inlets leading from said compartment into said collector, said inlets being inclined to direct the flow from said compartment into the collector substantially along the surface of said back wall.

2. The compressor of claim 1 in which said inlets are formed with walls which converge and then expand in the direction of flow to diffuse the flow and increase static pressure.

3. The compressor of claim 1 in which said inlets extend along straightlines in said back wall at an angle to a radius.

4. The compressor of claim 1 in which there are a plurality of said axially extending wall means arranged in concentric relation.

5. In an axial flow supersonic compressor the improvement comprising an annular compartment positioned to receive flow from the compressor blades and having a back wall means, means in said compartment defining a generally axially extending partition effectively dividing said compartment into radial inner and outer sub-compartments, said partitions curving arcuately in the direction of rotational flow from said blades thereby'reducing the velocity of supersonic flow by the generation of shock waves along the surfaces thereof, a collector positioned in axial relation to said subcompartments and separated therefrom by said wall means, and a plurality of inlet passages formed in said wall means leading from said compartment into said collector, said passages receiving the flows from said compartment, and being inclined at an angle to the axis so that the exit flow from said compartment is in the same rotational direction as the flow in said subcompartments.

6. The compressor of claim 5 inwhich there is provided a pair of said paritions dividing said compartment into radially outer, middle, and inner subcompartments.

7. The compressor of claim 5 in which said inlets are formed with throats which converge and then expand in the direction of fluid flow to diffuse the flow.

Claims

3. The compressor of claim 1 in which said inlets extend along straight lines in said back wall at an angle to a radius.

5. In an axial flow supersonic compressor the improvement comprising an annular compartment positioned to receive flow from the compressor blades and having a back wall means, means in said compartment defining a generally axially extending partition effectively dividing said compartment into radial inner and outer sub-compartments, said partitions curving arcuately in the direction of rotational flow from said blades thereby reducing the velocity of supersonic flow by the generation of shock waves along the surfaces thereof, a collector positioned in axial relation to said sub-compartments and separated therefrom by said wall means, and a plurality of inlet passages formed in said wall means leading from said compartment into said collector, said passages receiving the flows from said compartment, and being inclined at an angle to the axis so that the exit flow from said compartment is in the same rotational direction as the flow in said sub-compartments.

6. The compressor of claim 5 in which there is provided a pair of said paritions dividing said compartment into radially outer, middle, and inner sub-compartments.