Guider for air turbine starter

Abstract

The invention relates to the technical field of turbine guiders, in particular to a guider for an air turbine starter. According to the technical scheme, the guide device comprises a guide device body and a plurality of sets of blades, the inner ring of the guide device body is an inner ring, the outer ring of the guide device body is an outer ring, the outer ring of the outer ring is an installation edge, the axial shape of the installation edge is in the shape of five arc edges and a straight edge, and the blades are evenly installed between an inner flow channel face and an outer flow channel face in the axial direction. The rear portion of the guider body is arranged to be in the shape of two sets of step faces, the center of the rear portion of the guider body is in the shape of a cavity, and the front edges of the blades are airflow inlets. The guider is integrally and precisely cast and formed, the whole ring modeling is adopted, the structure is simple, the assembling operation of the guider body and the starter is convenient and fast through the arrangement of the bolt mounting holes, the overall weight can be reduced through the arrangement of the cavity, the overall flow texture is good, the strength is reliable, and meanwhile good corrosion resistance and abrasion resistance are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of turbine guide devices, and in particular to a guide device for an air turbine starter. Background Art

[0002] The air turbine starter (hereinafter referred to as the starter) is a small-sized turbine starter that uses compressed air to drive the engine gas generator rotor during ground and air starting. As an aviation auxiliary power device, the starter has many advantages such as simple structure, easy use, safety and reliability, and low cost.

[0003] When the starter is working, compressed air flows into the intake housing of the starter through the control valve. After expansion, the flow velocity increases when passing through the turbine guide. The high-speed airflow blows the impeller. At this time, the pressure energy and heat energy are converted into kinetic energy, causing the turbine to expand and do work. The shaft power obtained is transmitted through the gear reduction mechanism and the sprag clutch, and the torque is output through the output shaft assembly, driving the engine gas generator rotor to rotate.

[0004] The turbine guide is an important component of the starter, which requires reliable strength, good flow capacity, simple structure and other characteristics. Based on this, we specially propose a guide for an air turbine starter. Summary of the invention

[0005] The purpose of the present invention is to provide a guide for an air turbine starter in view of the problems existing in the background technology.

[0006] The technical solution of the present invention is as follows: A guide for an air turbine starter comprises a guide body and a plurality of groups of blades, wherein the inner ring of the guide body is an inner ring, the outer ring of the guide body is an outer ring, the outer ring of the outer ring is a mounting edge, the axial shape of the mounting edge is five arc edges and one straight edge, a plurality of groups of bolt mounting holes are provided on the mounting edge, the outer ring surface of the inner ring is an inner flow channel surface, the inner ring surface of the outer ring is an outer flow channel surface, the blades are axially evenly installed between the inner flow channel surface and the outer flow channel surface, the rear part of the guide body is a machined surface, two groups of step surfaces are arranged at the rear of the guide body, the rear center position of the guide body is a cavity, and the leading edge of the blade is an airflow inlet.

[0007] Preferably, the hole edge of the bolt mounting hole is convex outward relative to the arc edge and the straight line edge.

[0008] Preferably, the inner flow channel surface and the outer flow channel surface are both flat channels, and the inner flow channel surface and the outer flow channel surface are both casting surfaces, with a contour degree of 0.2 and a surface roughness of 1.6.

[0009] Preferably, the trailing edge of the blade is the airflow outlet.

[0010] Preferably, the guide body is made of aluminum alloy material, and the surface of the guide body is anodized and painted.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects:

[0012] The guide in the present invention is integrally precision cast and has a simple whole-ring structure. The arrangement of bolt mounting holes makes the assembly of the guide body and the starter quick and convenient. The arrangement of the cavity can reduce the overall weight. The overall flow organization is good, the strength is reliable, and the guide has good corrosion resistance and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 It is a front view of the present invention;

[0015] Figure 3 It is a side cross-sectional view of a part of the present invention;

[0016] Figure 4 It is a schematic diagram of the structure of the blade in the present invention.

[0017] Figure numerals: 1. guide body; 2. blades; 3. inner ring; 4. outer ring; 5. mounting edge; 6. arc edge; 7. straight edge; 8. bolt mounting hole; 9. inner flow channel surface; 10. outer flow channel surface; 11. step surface; 12. cavity. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] Example

[0020] like Figure 1-4As shown, a guide for an air turbine starter proposed by the present invention comprises a guide body 1 and a plurality of blades 2. The guide body 1 is made of aluminum alloy material, and the alloy is an aluminum-silicon-magnesium cast aluminum alloy that can be heat-treated and strengthened, has high mechanical properties and is light in weight. The guide body 1 is integrally precision cast and has a whole ring structure. The inner ring of the guide body 1 is an inner ring 3, the outer ring of the guide body 1 is an outer ring 4, the outer ring of the outer ring 4 is a mounting edge 5, the outer circular edge of the mounting edge 5 is chamfered, and the axial shape of the mounting edge 5 is five arc edges 6 and one straight edge 7, and the two top positions of each arc edge 6 are chamfered. Circular, two top ends of each arc edge 6 and the outer circular edge of the mounting edge 5 are short straight edges, multiple groups of bolt mounting holes 8 are provided on the mounting edge 5, and six groups of bolt mounting holes 8 are provided. The hole edges of the bolt mounting holes 8 are convex outward relative to the arc edge 6 and the straight edge 7. The angle of the bolt mounting hole 8 is determined according to the angle of the bolt hole of the turbine casing. The setting of the straight edge 7 at one end of the mounting edge 5 can better facilitate the operator to find the angle of the bolt mounting hole 8 when assembling the starter. The setting of the bolt mounting hole 8 can enable the guide body 1 to be connected and installed with the intake housing and the turbine casing through bolts when it is installed in conjunction with the starter;

[0021] The outer ring surface of the inner ring 3 is the inner flow channel surface 9, and the inner ring surface of the outer ring 4 is the outer flow channel surface 10. Both the inner flow channel surface 9 and the outer flow channel surface 10 are flat channels. Both the inner flow channel surface 9 and the outer flow channel surface 10 are casting surfaces with a contour of 0.2 and a surface roughness of 1.6. No reverse step can appear at the junction of the inlet chamfered surface of the inner ring 3 and the inner flow channel surface 9 along the airflow direction. The rear part of the guide body 1 is a machined surface with a surface roughness of 1.6. The machined surface is used in conjunction with the impeller to form an outer flow channel for the airflow at the impeller on the one hand, and to play a smaller containment role on the other hand. Two groups of step surfaces 11 are arranged at the rear of the guide body 1. The outer group of step surfaces 11 cooperates with the stop of the turbine casing, and the inner group of step surfaces 11 cooperates with the containment ring. The rear center position of the guide body 1 is in the shape of a cavity 12. The arrangement of the cavity 12 can reduce the weight of the parts.

[0022] The blades 2 are evenly installed axially between the inner flow channel surface 9 and the outer flow channel surface 10. There are 17 or 19 groups of blades 2. The surface of the blades 2 is a casting surface with a surface roughness of 1.6. The leading edge and the trailing edge of the blades 2 are not allowed to have flat heads, chamfered edges, sharp edges and necked states. The circumferential deviation of the multiple groups of blades 2 from the theoretical position is not greater than 0.2, and the axial deviation from the theoretical position is not greater than 0.2. The leading edge of the blade 2 is the airflow inlet, and the trailing edge of the blade 2 is the airflow outlet. The multiple groups of blades 2 adopt a transonic blade cascade design, and the airflow inlet Mach number is about 0.13. It expands and accelerates to a supersonic flow state in the blade cascade flow channel, reaching a post-cascade Mach number of 1.25. At the same time, the blade profile of the blade 2 adopts a convergent nozzle design, which can avoid the occurrence of the guide back pressure being lower than the critical pressure, resulting in nozzle blockage and affecting the blade cascade flow capacity;

[0023] The turbine guide vane is a static part, which is mainly affected by air pressure and loads such as vibration and impact during use. The air flow of the starter is controlled by the effective throat area of ​​the guide vane, which can be achieved by changing the number of guide vane 2 and the blade height of the guide vane 2. The surface of the guide vane body 1 is anodized and painted, and the guide vane is anodized with sulfuric acid as a whole. Since the arc edge 6 and the straight edge 7 are exposed to the external environment during use, additional painting treatment is adopted to make the parts have good corrosion resistance, wear resistance and other characteristics, and the overall structure is simple, light weight and reliable strength.

[0024] In this embodiment, the operator uses bolts to assemble the guide body 1 with the air intake housing and the turbine casing through the bolt mounting holes 8. At this time, the two sets of step surfaces 11 are respectively adapted and installed with the stopper and the containment ring of the turbine casing;

[0025] The flow in the turbine guide vane is well organized, there is no obvious secondary flow and flow separation on the blade basin surface of blade 2, and the aerodynamic loss is small; the intensity of the incident shock wave and the reflected shock wave generated between the back of blade 2 and the adjacent blade 2 is low, and no open separation bubble under a strong adverse pressure gradient occurs, so the aerodynamic performance of the guide vane is less affected;

[0026] When the turbine expansion ratio is supercritical, the expansion ratio is greater than 1.89. The throat area of ​​the guide determines the flow rate of the starter, and thus determines the output power of the starter. Therefore, appropriate starter output power requires a certain starter air flow rate, that is, the throat area of ​​the guide should be within an appropriate range.

[0027] If the throat area of ​​the guide is too small, the air flow rate will be small, which will make the output power of the starter small and cannot meet the predetermined power requirements;

[0028] If the throat area of ​​the guide is too large, the air flow will be large. Firstly, the air supply conditions may not allow it. Secondly, the excessive output power will make the starter and related parts larger and overweight, and may even cause damage to the parts.

[0029] The above specific embodiment is only a preferred embodiment of the present invention. Based on the technical solution of the present invention and the relevant inspiration of the above embodiment, those skilled in the art can make various alternative improvements and combinations to the above specific embodiment.

Claims

1. A guide for an air turbine starter, comprising a guide body (1) and a plurality of blades (2), characterized in that: The inner ring of the guide body (1) is an inner ring (3), the outer ring of the guide body (1) is an outer ring (4), the outer ring of the outer ring (4) is a mounting edge (5), the axial shape of the mounting edge (5) is in the form of five arc edges (6) and one straight edge (7), a plurality of bolt mounting holes (8) are provided on the mounting edge (5), the outer ring surface of the inner ring (3) is an inner flow path surface (9), the inner ring surface of the outer ring (4) is an outer flow path surface (10), the blades (2) are axially evenly mounted between the inner flow path surface (9) and the outer flow path surface (10), the rear of the guide body (1) is a machined surface, two sets of step surfaces (11) are arranged at the rear of the guide body (1), the rear center of the guide body (1) is in the form of a cavity (12), and the leading edge of the blade (2) is an airflow inlet.

2. A guide for an air turbine starter according to claim 1, characterized in that: The hole edge of the bolt mounting hole (8) is convex outward relative to the arc edge (6) and the straight edge (7).

3. A guide for an air turbine starter according to claim 2, characterized in that: The inner flow channel surface (9) and the outer flow channel surface (10) are both flat channels, and the inner flow channel surface (9) and the outer flow channel surface (10) are both casting surfaces, with a contour degree of 0.2 and a surface roughness of 1.

6.

4. A guide for an air turbine starter according to claim 3, characterized in that: The trailing edge of the blade (2) is the airflow outlet.

5. A guide for an air turbine starter according to claim 4, characterized in that: The guide body (1) is made of aluminum alloy material, and the surface of the guide body (1) is anodized and painted.

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