CN104895841B - Rectifier, flow passage structure, combined compressor, aero gas turbine engine - Google Patents

Abstract

A combined compressor flow path structure, comprising: a single-stage axial flow compressor with an axial flow impeller; a rectifier with a negative curvature flow path; and a centrifugal compressor with a centrifugal impeller, wherein: the negative curvature flow path is formed along the circumferential direction Consists of uniformly distributed and spaced pipes; the inlet of the pipe is connected to the outlet of the axial flow compressor, and the outlet of the pipe is connected to the centrifugal compressor; the average radius of the inlet of the axial flow impeller (R1) is smaller than the average radius of the inlet of the pipe (R2) , the average outlet radius (R3) of the pipes is smaller than the average inlet radius (R2) of the pipes, and the ratio of the outlet flow area to the inlet flow area of each pipe falls within the range of 1.2-1.4. The invention also relates to a rectifier, a combined compressor and an aviation gas turbine engine with negative curvature flow passages. The use of negative curvature pipeline rectifiers can meet the dual requirements of high working capacity of axial flow compressors and low hub ratio of centrifugal compressors, and avoid the problem of air separation at the root of blade rectifiers.

Description

Rectifier, runner structure, combined compressor, aviation gas turbine engine

technical field

The embodiments of the present invention relate to the field of aero-engines, and in particular to a rectifier with a negative curvature flow channel, a flow channel structure of a combined compressor, a combined compressor with the flow channel structure, and an aviation gas turbine engine with the combined compressor.

technical background

Unlike high-thrust aero-engines that use a multi-stage axial flow compressor with large flow and high pressure ratio, the combined compressor is the main structural type of the compression system of small and medium-thrust aero-engines.

Axial flow + centrifugal combined compressor combines the characteristics of smooth axial flow channel, high efficiency, small flow rate of centrifugal stage, wide working range, few parts and high reliability, and is widely used in small and medium flow aviation gas turbine engines.

For modern high-performance axial flow + centrifugal combined compressors, no transition section design is usually used between stages. Due to the cancellation of the transition section, the axial length of the combined compressor is shorter and the efficiency is higher. However, the design without a transition section also brings certain difficulties to the optimization of the axial flow stage and the centrifugal stage and the matching of the two. For the axial flow stage, it is necessary to increase the outlet diameter of the axial flow impeller to increase its working capacity and achieve a higher single-stage pressure ratio, thereby reducing the number of parts, weight and manufacturing cost of the compressor; while for the centrifugal impeller In general, large inlet area, small inlet Mach number and small inlet hub diameter are required to ensure high efficiency and surge margin of the centrifugal stage, which is contradictory to the larger hub ratio of the axial flow stage outlet , the reduction of the outlet hub diameter of the axial flow rectifier will lead to the increase of the root load of the axial flow rectifier, the flow separation and the large loss and other adverse effects.

Therefore, it is urgent to explore a new combined compressor flow channel structure that takes into account the dual requirements of high outlet/inlet average radius ratio of axial compressor (enhanced working capacity) and low inlet hub ratio of centrifugal compressor.

Contents of the invention

In order to overcome the problems of low single-stage pressure ratio, large number of stages, heavy weight and high manufacturing cost of existing multi-stage axial flow or axial flow-centrifugal combined compressors used in existing small and medium-sized aviation gas turbine engines, the present invention is proposed.

According to an aspect of an embodiment of the present invention, a rectifier with a negative curvature flow channel is proposed, the inlet of the rectifier is suitable for communicating with an axial flow compressor, and the outlet is suitable for communicating with a centrifugal compressor, and the rectifier includes : Inner annulus; Outer annulus; Negative curvature flow passage arranged between the inner annulus and the outer annulus, the negative curvature flow passage is composed of a plurality of negative curvature pipes, the pipes are evenly distributed in the circumferential direction and spaced apart from each other open and spaced apart from each other and the ratio of the outlet flow area to the inlet flow area of each pipe falls within the range of 1.2-1.4.

Optionally, the cross-sectional shape of the pipe is circular, elliptical or quasi-elliptical.

Optionally, the angle between the centerline of each pipeline and the axis of rotation of the axial flow compressor is 25° to 45°; the dimensionless ratio L/H of each pipeline is less than 1.5, where L is the axial length of the pipeline , H is the radial height of the pipe outlet.

According to another aspect of the embodiments of the present invention, a flow path structure of a combined compressor is also proposed, including: a single-stage axial flow compressor as the first stage, with an axial flow impeller; a rectifier with a negative curvature flow path ; and as a second-stage centrifugal compressor, having a centrifugal impeller, wherein: the rectifier is the above-mentioned rectifier; the inlet of each pipeline communicates with the outlet of the axial flow compressor, and the outlet of each pipeline communicates with the centrifugal compressor; The average radius of the inlet of the axial flow impeller is smaller than the average radius of the inlet of the pipe, and the average radius of the outlet of the pipe is smaller than the average radius of the inlet of the pipe.

Optionally, the number of the pipes is 1.5 to 2 times the number of blades of the axial flow impeller.

Optionally, the number of pipes is 1.5-2 times the number of blades of the centrifugal impeller.

Optionally, the outlet of the duct is offset in the circumferential direction relative to the inlet of the duct, and the offset direction is consistent with the rotation direction of the axial flow impeller.

The embodiment of the present invention also relates to a combined compressor, comprising: a rotating shaft; the flow channel structure of the above-mentioned combined compressor; a radial diffuser arranged downstream of the centrifugal impeller; and a shaft arranged downstream of the radial diffuser To the diffuser, wherein the axial flow impeller and the centrifugal impeller of the combined compressor rotate around the axis of the rotating shaft.

The embodiment of the present invention also relates to an aviation gas turbine engine, including the above combined compressor.

The combined air compressor based on the technical scheme of the invention has the advantages of simple and compact structure, few parts, short rotor length and low processing and maintenance costs.

Description of drawings

Fig. 1 is a schematic view of the flow path of a combined compressor with a negative curvature duct rectifier according to an embodiment of the present invention.

Fig. 2 is a three-dimensional schematic diagram of a combined compressor with a negative curvature pipeline rectifier according to the present invention.

Explanation of reference numerals: axial flow impeller 1 , rectifier 2 , centrifugal impeller 3 , radial diffuser 4 , axial diffuser 5 , compressor shaft 6 .

Detailed ways

The technical solution of the present invention will be further specifically described below through the embodiments and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals designate the same or similar bottom members. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention, but should not be construed as a limitation of the present invention.

As shown in Figure 1, the present invention proposes a rectifier 2 with a negative curvature flow channel, the inlet of the rectifier 2 is suitable for communicating with the axial flow compressor (represented by the axial flow impeller 1 in Figure 1), and the outlet It is suitable for communicating with a centrifugal compressor (represented by a centrifugal impeller 3 in FIG. 1 ). Referring to Figures 1 and 2, the rectifier 2 includes: an inner ring surface 21; an outer ring surface 22; a negative curvature flow channel arranged between the inner ring surface and the outer ring surface, and the negative curvature flow channel is composed of a plurality of negative curvature pipes 23 , the pipes 23 are evenly distributed in the circumferential direction and spaced apart from each other, and the ratio of the outlet flow area to the inlet flow area of each pipe 23 falls within the range of 1.2 to 1.4, for example, the ratio can be 1.2, 1.25, 1.3, 1.35 , 1.4, in order to achieve the maximum rectification of the air flow under the premise of ensuring that the flow in the rectifier is not separated.

With this rectifier 2 it is possible to evenly distribute the gas flow from the axial compressor upstream of the rectifier to the centrifugal compressor downstream of the rectifier.

The blade type rectifier is used in the prior art, but the blade type rectifier has the problems of large curvature change and difficult processing, and there is airflow separation at the root of the blade, while the pipeline type negative curvature rectifier of the present invention has simple structure and low processing cost. Low, while avoiding the separation of the blade root under the negative curvature flow channel, it can maximize the performance of the rectifier.

The rectifier can be made of steel, in particular a pipe can be drilled directly between the inner and outer rings in a steel ring with negative curvature. The rectifier can also be made in one piece by casting process.

Optionally, the cross-sectional shape of the pipe is circular, elliptical or quasi-elliptical. In this way, the pipes intersect to form a dovetail leading edge, which can better adapt to the uneven flow at the outlet of the axial flow impeller and improve the performance of the rectifier.

As shown in Figure 1, optionally, the angle θ between the center line of each pipeline and the rotation axis of the combined compressor is 25° to 45°, and the dimensionless ratio L/H of each pipeline is less than 1.5 to ensure that the rectifier It has high total pressure recovery performance and outlet flow field uniformity, where L is the axial length of the pipeline, and H is the radial height of the pipeline outlet. θ can be 25 degrees, 30 degrees, 45 degrees.

Correspondingly, the present invention also proposes a flow path structure of a combined compressor, as shown in Figure 1, the flow path structure includes: a single-stage axial flow compressor as the first stage, with an axial flow impeller 1; the above-mentioned A rectifier 2 with a negative curvature flow path; and a centrifugal compressor as the second stage, with a centrifugal impeller 3, wherein: the inlet of each pipeline 23 communicates with the outlet of the axial flow compressor, and the outlet of each pipeline 23 communicates with the centrifugal compressor. The machine is connected; and the average radius R1 of the inlet of the axial flow impeller is smaller than the average radius R2 of the inlet of the pipeline, and the average radius R3 of the outlet of the pipeline is smaller than the average radius R2 of the inlet of the pipeline.

As shown in Figure 1, the flow channel of the axial flow compressor is gradually raised from the inlet, so that the average radius R1 of the inlet of the axial flow impeller is smaller than the average radius R2 of the inlet of the pipeline, and the outer diameter of the flow channel at the outlet of the axial flow impeller can be increased by increasing the function The average radius R3 of the outlet of the pipeline 23 is smaller than the average radius R2 of the inlet of the pipeline 23, which can effectively reduce the hub ratio of the centrifugal impeller inlet, meet the requirements of the inlet of the centrifugal compressor, and reduce the design difficulty of the centrifugal compressor.

Since the outlet of the pipeline 23 communicates with the passage between the blades of the centrifugal impeller, and the outlet area of the pipeline 23 is greater than the inlet area of the pipeline 23, therefore, preferably, also consider the difference between the number of the pipeline 23 and the number of centrifugal impeller blades relation. Optionally, the number of ducts 23 is 1.5 to 2 times the number of axial flow blades, for example, 1.5 times, 2 times or 1.7 times the number of axial flow blades. In the case that the pipes 23 are evenly distributed along the circumferential direction, this can ensure that the rectifier has high total pressure recovery performance and uniformity of the outlet flow field.

In order to reduce flow loss, optionally, the outlet of the pipe 23 is offset in the circumferential direction relative to the inlet of the pipe 23, and the offset direction is consistent with the rotation direction of the axial flow impeller. For example, in Fig. 2, when the blades of the axial impeller 1 rotate in the clockwise direction, the outlet of the duct 23 is offset in the clockwise direction relative to the inlet.

According to the channel structure of the combined compressor of the present invention, one of at least one of the following advantages can be obtained relative to the flow channel layout of the traditional combined compressor: ① the single-stage pressure ratio of the axial flow compressor is high, which can reduce the number of parts of the compressor. Much less, simple and compact structure, significantly reducing the cost of processing, installation and maintenance; ②The front stage uses a high-pressure ratio single-stage axial flow compressor instead of a multi-stage axial flow compressor to shorten the support span and reduce the difficulty of shafting design; ③The front stage The wide-chord design of the stage adopts the axial-flow compressed air distortion tolerance, and the foreign object impact resistance (FOD) is strong. At the same time, the Reynolds number based on the blade chord length is increased, and it has higher performance under the condition of high altitude and low Reynolds number.

As shown in Figure 1, the present invention also proposes a kind of combination compressor, comprises: rotating shaft 6; The channel structure of above-mentioned combination compressor; The radial diffuser 4 that is arranged on the centrifugal impeller downstream; An axial diffuser 5 downstream of the diffuser 4, wherein the axial flow impeller and the centrifugal impeller of the combined compressor rotate around the axis of the rotating shaft.

The operation of the combined compressor is described below. When the combined compressor is working, the axial flow impeller 1 and the centrifugal impeller 3 rotate around the compressor axis 6, and the air flow is introduced into the axial flow impeller 1 from the intake casing, and after being pressurized by the axial flow impeller 1, it flows into the rectifier 2 for rectification, and after After being rectified and diffused, it enters the centrifugal impeller 3, and after being further pressurized by the centrifugal impeller 3, it enters the vane radial diffuser 4, where it decelerates and pressurizes, and then passes through the axial diffuser 5 for further rectification, and finally flows into the combustion chamber.

The axial flow-centrifugal combined compressor according to the present invention has a large humpback flow channel, which can meet the dual requirements of high working capacity of the axial flow compressor and low hub ratio of the centrifugal compressor, because the single-stage axial flow compressor has a higher The stage pressure ratio, therefore, can replace the multi-stage axial flow compressor in front of the axial flow-centrifugal combined compressor, so that the number of parts of the compressor is greatly reduced, the structure is simple and compact, and the cost of processing, installation and maintenance is significantly reduced.

The combined air compressor according to the present invention can be applied to aviation gas turbine engines, especially high-performance small and medium-sized aviation gas turbine engines.

While embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by The appended claims and their equivalents are defined.

Claims (9)

1. a kind of rectifier with negative cruvature runner, the entrance of the rectifier is suitable to communicate with axial flow compressor, and exports Suitable for being communicated with centrifugal compressor, the rectifier includes：

Inner ring surface；

Outer ring surface；

The negative cruvature runner being arranged between inner ring surface and outer ring surface,

Characterized in that,

The negative cruvature runner is made up of multiple negative cruvature pipelines, and negative cruvature pipeline is uniform in a circumferential direction and is spaced Open and the ratio between the outlet stream area of each negative cruvature pipeline and entrance circulation area are fallen into the range of 1.2~1.4, bear The entrance mean radius (R2) of curvature pipeline is more than axial wheel entrance mean radius (R1).

2. rectifier according to claim 1, wherein：

The cross sectional shape of the negative cruvature pipeline is circular, ellipse or class ellipse.

3. rectifier according to claim 1 or 2, wherein：

The angle of the center line of each negative cruvature pipeline and the rotation axis of axial flow compressor is 25 °~45 °；

The non-dimensional ratio L/H of each negative cruvature pipeline is less than 1.5, wherein, L is the axial length of negative cruvature pipeline, and H is negative The radial height of curvature pipe outlet.

4. a kind of flow passage structure of combined compressor, including：

As the single-stage axial compressor of the first order, there is axial wheel；

Rectifier with negative cruvature runner；With

As the centrifugal compressor of the second level, there is centrifugal impeller,

Wherein：

The rectifier is the rectifier according to any one of claim 1-3；

The entrance of each negative cruvature pipeline and the outlet of axial flow compressor, the outlet and centrifugation of each negative cruvature pipeline Compressor connects；

Axial wheel entrance mean radius (R1) is less than the entrance mean radius (R2) of negative cruvature pipeline, the outlet of negative cruvature pipeline Mean radius (R3) is less than the entrance mean radius (R2) of negative cruvature pipeline.

5. the flow passage structure of combined compressor according to claim 4, wherein：

The number of the negative cruvature pipeline is 1.5~2 times of the axial wheel number of blade.

6. the flow passage structure of combined compressor according to claim 4, wherein：

The number of the negative cruvature pipeline is 1.5~2 times of centrifugal impellers blades number.

7. the flow passage structure of combined compressor according to claim 4, wherein：

The outlet of the negative cruvature pipeline relative to the negative cruvature pipeline entrance it is along the circumferential direction upper offset, offset direction with The direction of rotation of axial wheel is consistent.

8. a kind of combined compressor, including：

Rotating shaft；

The flow passage structure of combined compressor according to any one of claim 4-7；

It is arranged on the radial diffuser in centrifugal impeller downstream；And

The axial diffuser in radial diffuser downstream is arranged on,

Wherein, the axis rotation of the axial wheel of the combined compressor and centrifugal impeller around the shaft.

9. a kind of aero gas turbine engine, including：

Combined press mechanism of qi according to claim 8.