WO1999002864B1

WO1999002864B1 - High pressure centrifugal compressor

Info

Publication number: WO1999002864B1
Application number: PCT/IL1998/000310
Authority: WO
Filing date: 1998-07-02
Publication date: 1999-02-25

Abstract

A multi stage compressor includes a first stage centrifugal compressor (1) with an axial inducer (2) and a number of radial outlets (4), and a second stage centrifugal compressor (6) with a rotating vaned disk (15) mounted to rotate coaxially with the first stage centrifugal compressor (1). The second stage compressor includes radial inlets (5).

Claims

AMENDED CLAIMS[received by the International Bureau on 12 January 1999 (12.01.99); original claims 1-8 replaced by amended claims 1-10 (4 pages)]

1. A multi-stage centrifugal compressor for compressing a fluid, the compressor comprising:

(a) a first centrifugal compressor stage including an mducer rotatably mounted about a virtual central axis, said inducer having a plurality of vanes defining a first stage inlet and a peripheral first stage outlet;

(b) a second centrifugal compressor stage including a rotor rotatably mounted about said virtual central axis, said rotor having a plurality of vanes deployed in an annular configuration having an inner periphery defining a second stage inlet and an outer periphery defining a second stage outlet, said second stage inlet circumscribing said first stage outlet;

(c) first rotation means configured to rotate said first centrifugal compressor stage at a first angular velocity; and

(d) second rotation means configured to rotate said second centrifugal compressor stage at a second angular velocity, said second angular velocity being co-directional with, but less than, said first angular velocity.

2. The compressor of claim 1, wherein a configuration of said first centrifugal compressor stage together with said first angular velocity defines a first stage fluid outlet velocity, and wherein a configuration of said second centrifugal compressor stage together with said second angular velocity defines a second stage fluid inlet velocity, a relative velocity defined as the difference between said first stage fluid outlet velocity and said second stage fluid inlet velocity being subsonic.

3. The compressor of claim 2, wherein said first stage fluid outlet velocity is supersonic.

4. The compressor of claim 3, wherein a configuration of said second centrifugal compressor stage together with said second angular velocity defines a second stage fluid outlet velocity, said second stage fluid outlet velocity being subsonic.

5. The compressor of claim 1, wherein said second rotation means includes a gear assembly in engagement with said inducer so as to receive rotational energy from said first centrifugal compressor stage.

6. The compressor of claim 1, fiαrther comprising a turbojet engine including a first shaft rotating at a first speed and a second shaft rotating at a second speed less than said first speed, wherein said first rotation means includes a mechanical connection to said first shaft and said second rotation means includes a mechanical connection to said second shaft. 10

7. A method for compressing a compressible fluid, there being defined a given speed of sound within the fluid, the method comprising:

(a) providing a multi-stage centrifugal compressor having n centrifugal compression stages, where n is at least 2, deployed in a concentric series centered about an axis of rotation, an innermost of said stages being referred to as the first stage and an outermost of said stages being referred to as the n'th stage, each of said stages including a set of vanes defining an inlet and an outlet; and

(b) rotating said stages such that all of said stages rotate in a common rotational direction, each stage having an angular velocity φ,- where i is an integer assuming values from 1 to n, wherein the values of φ,- are chosen such that:

(i) an outlet velocity of said first stage is greater than the speed of sound; (ii) an outlet velocity of said w'th stage is less than the speed of sound; and (iii) a difference between an outlet velocity of the /th stage and an input velocity of the (/^'+l)'th stage is less than the speed of sound fory from 1 to «-l.

8. The method of claim 7 , wherein «=2. 11

9. The method of claim 7, wherein the first stage is rotated by mechanical connection to an external power source, and wherein each stage other than the first stage is rotated by connection through a step-down transmission to the first stage.

10. The method of claim 7, wherein the first stage is rotated by mechanical connection to a first shaft of a turbojet engine, and the second stage is rotated by mechanical connection to a second shaft of said turbojet engine.