CN102678590B - Ultra-compact high pressure ratio oblique flow-centrifugal combined compressor structure - Google Patents

Abstract

The invention discloses an ultra-compact high-pressure ratio diagonal flow-centrifugal combined compressor structure, which relates to the compressor technology, which has two stages of a diagonal flow compressor and a centrifugal compressor, the first stage is a diagonal flow compressor, and the second stage is a For the centrifugal compressor, the key is to adopt a small-diameter "S" elbow connection structure between the diagonal flow compressor and the centrifugal compressor. The structure of the present invention can be directly used in aviation gas turbine engines, and has many advantages such as simple structure, few parts, compact structure, high reliability, and low processing and maintenance costs, and can solve the problem of using many small and medium-sized aviation gas turbine engines in China. The single-stage axial flow compressor and the axial flow-centrifugal combined compressor have the problems of low single-stage pressure ratio, many stages, heavy weight, high manufacturing cost, and the large radial scale of the two-stage centrifugal compressor.

Description

Ultra-compact High Pressure Ratio Diagonal Flow-Centrifugal Combined Compressor Structure

technical field

The invention relates to the technical field of compressors, and is an ultra-compact high-pressure ratio oblique flow-centrifugal combined compressor structure, which is especially suitable for high-performance aviation gas turbine engines.

Background technique

The biggest difference between various types of small and medium thrust aviation gas turbine engines is reflected in the difference in the type of compressor components, which is different from the structural form of a multi-stage axial flow compressor with large flow rate and high pressure ratio used in large thrust aviation engines, and the compression system of small and medium thrust aviation engines adopts Combined compressor. However, there are also full-axial flow compressors, such as WS500, whose high-pressure compressor uses a 5-stage axial flow compressor. The advantages of multi-stage axial flow compressors are smooth flow channels and high efficiency, but the disadvantages are also obvious: ①Multi-stage Axial flow compressors have a large number of components and high cost; ②Low distortion tolerance and poor resistance to foreign object damage; ③As the pressure ratio increases, the channel height of the subsequent stage becomes smaller and smaller, the blades are short and thin, and the entire compressed air When all compressors use axial flow stages, the efficiency of the subsequent stages will be very low, and the difficulty of blade processing will be increased; ④The single-stage pressure ratio of the axial flow compressor is low. The rotor dynamics problem will occur due to the long span of the rotor; ⑤ Due to the difficulty in matching between the stages of the small multi-stage axial flow compressor, the stability margin of the compressor at low and medium speeds is small. In order to expand the stable working range, The first few stages of stator blades are often adjustable or an air release mechanism is installed. The introduction of complex blade adjustment and air release mechanisms and corresponding control systems further increases the structural complexity, making the improvement of the thrust-to-weight ratio of the engine encounter a bottleneck. Axial flow-centrifugal/diagonal flow combination compressor combines the characteristics of smooth flow path of axial flow stage, high efficiency and small flow rate of centrifugal stage, wide working range, few parts and high reliability, and is widely used in engines with small and medium flow rates. Several latest foreign engines such as GE's T700 engine, Williams' F107 engine and Honeywell's TFE731 engine all use axial-centrifugal combined compressors. However, due to the existence of the axial flow stage, the axial flow-centrifugal combined compressor is also difficult to avoid the above-mentioned disadvantages of the multi-stage axial flow compressor; the two-stage centrifugal compressor has the advantages of simple structure, few parts, high reliability and processing maintenance. Low cost and other advantages, however, the radial size of the two-stage centrifugal compressor is larger, which increases the windward area and weight of the engine, and increases the force acting on the bearing, which increases the difficulty of bearing design and reduces the life of the bearing. Therefore, it is urgent to explore a new structural layout of combined compressors.

Contents of the invention

In order to overcome the existing problems of multi-stage axial flow compressors, axial flow-centrifugal/diagonal flow combined compressors and double-stage centrifugal compressors of aero-engines, the purpose of the invention is to propose an ultra-compact diagonal flow-centrifugal combination compressor structure , which has many advantages such as simple structure, few parts, compact structure, high reliability and low processing and maintenance costs.

In order to achieve the above object, technical solution of the present invention is:

An ultra-compact high-pressure ratio diagonal flow-centrifugal combined compressor structure, suitable for high-performance small and medium-sized aero-engines; it includes two stages of a diagonal flow compressor and a centrifugal compressor, the first stage is a diagonal flow compressor, and the second stage is a For the centrifugal compressor, a section of "S" elbow connection structure is adopted between the diagonal flow compressor and the centrifugal compressor. The inlet of the "S" elbow is fixedly connected with the outlet of the diagonal flow compressor, and the outlet is fixedly connected with the inlet of the centrifugal compressor. .

The oblique flow-centrifugal combined compressor structure has blades inside the "S" bend, and the inlet diameter of the "S" bend is larger than the outlet diameter of the "S" bend, and the "S" bend The area of the pipe channel has experienced a process of first increasing and then decreasing to ensure a good flow state in the "S" bend.

In the oblique flow-centrifugal combined compressor structure, the blades in the "S" bend are arranged in a row at the inlet of the "S" bend along the circumference with a 45°-60° For the wedge-shaped rectifier blades with installation angles, a row of reflux blades extending radially with an installation angle of 25° to 40° is arranged at the outlet along the circumference, and the inlets of the two rows of blades are aligned with the outlet airflow direction of the upstream blades.

In the structure of the oblique flow-centrifugal combined compressor, the reflux blades in the "S" elbow can rectify the airflow with 45-75° pre-rotation at the outlet of the oblique-flow rotor into a centrifugal impeller inlet with 15-75° 0° pre-swirled airflow.

In the structure of the oblique flow-centrifugal combined compressor, the oblique flow stage pressure ratio is 4.0-6.0:1, and the centrifugal stage pressure ratio is 2.0-3.0:1.

The structure of the diagonal flow compressor and the centrifugal compressor, the "S" elbow connection of a novel structure is adopted between the diagonal flow compressor and the centrifugal compressor, which is comparable to the two-stage centrifugal compressor with the same design parameters Compared with it, its radial size can be reduced by 25%, and the structure is more compact.

In the structure of the oblique flow-centrifugal combined compressor, the oblique flow impeller of the oblique flow compressor and the centrifugal impeller of the centrifugal compressor are axially tensioned by a central tie rod to form a rigid whole, and the oblique flow impeller and the centrifugal impeller Installed on the same shaft; when working, the turbine transmits torque through the arc-shaped end teeth, driving the oblique flow impeller and the centrifugal impeller to rotate around the engine axis together.

The beneficial effects of the present invention are:

(1) The single-stage pressure ratio of the diagonal flow compressor is high, and the front stage adopts the diagonal flow compressor instead of the multi-stage axial flow 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 ;

(2) The front stage uses a diagonal flow compressor instead of a multi-stage axial flow compressor to shorten the support span and reduce the difficulty of shafting design;

(3) The wide-chord design of the front stage adopts the oblique flow air pressure with high distortion tolerance, strong resistance to foreign object impact (FOD), and is insensitive to the gap and the surface finish of the blade;

(4) The oblique flow-centrifugal combined compressor has a wide stable working range, which can save the inlet guide vane, complex blade adjustment mechanism and corresponding control system;

(5) Compared with the structural layout of the two-stage centrifugal compressor, the use of a diagonal flow compressor in the front stage can overcome the limitation of the small flow rate of the two-stage centrifugal compressor; at the same time, a novel structural S Elbow connection, on the one hand, avoids the problem of large radial dimension of the two-stage centrifugal compressor, on the other hand, reduces the force acting on the bearing and increases the life of the bearing.

Description of drawings

Fig. 1 is the structure schematic diagram of ultra-compact high pressure ratio oblique flow-centrifugal combined compressor of the present invention; Wherein:

Diagonal flow impeller disc 1 inner wall part 2 inner wall part 3

Centrifugal impeller disc 4 central tie rod 5 axis 6

Slant flow rotor blades 7 Arc end teeth 8 Straightener blades 9

Outer wall part 10 reflux vane 11 outer wall part 12

Outer wall parts 13 Centrifugal rotor blades 14 Radial diffuser blades 15

Axial diffuser vanes 16

Detailed ways

Referring to Fig. 1, the structure of the ultra-compact high-pressure ratio oblique flow-centrifugal combined compressor of the present invention consists of oblique flow impellers, small-diameter "S" elbows with rectifiers and return blades, centrifugal impellers, radial diffusers and shafts. The diffuser is composed of six parts, the oblique flow impeller is composed of oblique flow impeller disk 1 and oblique flow rotor blade 7, the centrifugal impeller is composed of centrifugal impeller disk 4 and centrifugal rotor blade 14, and the oblique flow impeller and centrifugal impeller pass through An ultra-compact "S" elbow with small radial size is connected. The inner wall of the "S" elbow is composed of inner wall parts 2 and inner wall parts 3, and the outer wall of the elbow is composed of outer wall parts 10, outer wall parts 12 and outer wall parts 13. A row of rectifier blades 9 is arranged at the inlet of the elbow, and a row of reflux blades 11 is arranged at the outlet. The oblique flow impeller and the centrifugal impeller are tensioned axially through the center tie rod 5 to form a rigid whole. The oblique flow impeller and the centrifugal impeller are installed on the same shaft. When the combined compressor is working, the turbine is twisted to the centrifugal impeller through the arc end teeth 8 The disk 4 drives the oblique flow impeller and the centrifugal impeller to rotate around the engine axis 6 together.

The ultra-compact high-pressure ratio diagonal flow-centrifugal combined compressor structure of the present invention, the compressor is composed of two stages of a diagonal flow compressor and a centrifugal compressor, the first stage is a diagonal flow compressor, the second stage is a centrifugal compressor, and the oblique flow compressor is a centrifugal compressor. The flow compressor and the centrifugal compressor are connected by a small-diameter "S" elbow with a novel structure. When the compressor is working, the air flow is introduced into the working blades of the first-stage diagonal flow compressor from the converging channel of the intake casing. After being pressurized by the working blade 7, it flows into the axial flow rectifier 9, and after being rectified and diffused, it enters the centrifugal rotor blade 14 of the second-stage centrifugal compressor through a section of small-diameter "S" elbow (with reflux blade 11) After being further pressurized by the centrifugal impeller, it enters the vane radial diffuser 15, where it decelerates and pressurizes, and then passes through the axial diffuser 16 to further diffuse, rectify, and finally flow into the combustion chamber.

In summary, the present invention can be directly used in aviation gas turbine engines, and has many advantages such as simple structure, few parts, compact structure, high reliability and low processing and maintenance costs, and can solve the problem of existing domestic small and medium-sized aviation gas turbine engines. Turbine engines adopt multi-stage axial flow compressors, axial flow-centrifugal combined compressors have the problems of low single-stage pressure ratio, many stages, heavy weight, high manufacturing cost and large radial scale of double-stage centrifugal compressors .

Claims (5)

1. A high-pressure ratio diagonal flow-centrifugal combined compressor structure, suitable for small and medium-sized aero-engines; it is characterized in that: it includes two stages of a diagonal flow compressor and a centrifugal compressor, the first stage is a diagonal flow compressor, and the second stage It is a centrifugal compressor, and a section of "S" elbow connection structure is adopted between the diagonal flow compressor and the centrifugal compressor. The inlet of the "S" elbow is fixedly connected with the outlet of the diagonal flow compressor, and the outlet is fixed catch; Among them, the "S" elbow has blades inside, and the inlet diameter of the "S" elbow is larger than the outlet diameter of the "S" elbow, and the area of the "S" elbow channel has experienced a first increase and then a decrease. process to ensure that there is no flow separation in the "S" bend; For the blades in the "S" bend, a row of wedge-shaped rectifier blades with an installation angle of 45° to 60° is arranged at the inlet of the "S" bend along the circumference, and a row of Row radially extending reflux blades with an installation angle of 25° to 40°. At the same time, the inlet of the wedge-shaped rectifier blade is aligned with the airflow direction of the outlet of the upstream oblique flow rotor blade, and the inlet of the reflux blade is aligned with the airflow direction of the outlet of the upstream wedge-shaped rectifier blade. 2. The structure of the high-pressure ratio oblique flow-centrifugal combined compressor according to claim 1, characterized in that: the rectifier blades and reflux blades in the "S" elbow can make the oblique flow rotor outlet have 45~ The 75° pre-swirled air flow is rectified into a 15-0° pre-swirled air flow at the inlet of the centrifugal impeller. 3. The structure of high-pressure ratio diagonal flow-centrifugal combined compressor according to claim 1, characterized in that: the pressure ratio of the diagonal flow stage is 4.0-6.0:1, and the pressure ratio of the centrifugal stage is 2.0-3.0:1. 4. The structure of high pressure ratio diagonal flow-centrifugal combined compressor according to claim 1, characterized in that: compared with the two-stage centrifugal compressor structure with the same design parameters, the high pressure ratio diagonal flow-centrifugal combined compressor structure is The radial dimension can be reduced by 25%. 5. The structure of high-pressure ratio mixed-flow-centrifugal combined compressor according to claim 1, characterized in that: the mixed-flow impeller of the mixed-flow compressor and the centrifugal impeller of the centrifugal compressor are pulled axially by a central pull rod Tightly forming a rigid whole, the oblique flow impeller and the centrifugal impeller are installed on the same shaft; when working, the turbine is twisted to the combined compressor through the arc end teeth, driving the oblique flow impeller and the centrifugal impeller to rotate around the engine axis together.