Centrifugal compressor suitable for mixed flow compression system

Abstract

The invention discloses a centrifugal compressor suitable for a mixed-flow compression system. At present, due to the adoption of a two-stage centrifugal compressor, the efficiency is reduced due to too many turning of a flow channel, and meanwhile, complexity is caused when double shafts are adopted. The centrifugal compressor comprises a centrifugal impeller, an impeller end cover, a centrifugal compressor casing, a diffusion section, an outlet guide vane assembly and a vane back sealing body. The centrifugal impeller is in clearance fit with the impeller end cover, and the impeller end cover is fixed with the centrifugal compressor casing through a bolt; a diffusion section is fixed above an outlet of the centrifugal impeller through a bolt, and the outlet side of the diffusion section is fixed to the outlet guide vane assembly. The invention is applied to the centrifugal compressor suitable for the mixed-flow compression system.

Description

Technical Field

[0001] The invention relates to a centrifugal compressor suitable for a mixed flow compression system. Background Art

[0002] Centrifugal compressors are widely used in various fields of the national economy. As industrial equipment gradually develops towards large-scale, large-flow, high-performance centrifugal compressors are currently the hot spot for research by many scientific researchers. The mixed-flow compression system takes into account the characteristics of centrifugal compressors and axial-flow compressors. While ensuring the aerodynamic performance requirements of the compressor, it is more suitable for the working requirements of large-flow conditions, and is therefore more suitable for use in large-flow centrifugal compressors. The current small and medium-flow engines and gas turbine axial-flow compressors have a small height of the last-stage blades and low efficiency as the pressure ratio increases. Summary of the invention

[0003] The object of the present invention is to solve the above-mentioned problems and thereby provide a centrifugal compressor suitable for a mixed flow compression system.

[0004] The above purpose is achieved through the following technical solutions: A centrifugal compressor suitable for a mixed flow compression system comprises a centrifugal impeller, an impeller end cover, a centrifugal compressor casing, a diffuser section, an outlet guide vane assembly and a blade back seal; The centrifugal impeller and the impeller end cover are clearance-matched, and the impeller end cover and the centrifugal compressor casing are fixed by bolts; A diffuser section is fixed above the centrifugal impeller outlet by bolts, and the outlet side of the diffuser section is fixed to the outlet guide vane assembly.

[0005] The centrifugal compressor is suitable for a mixed flow compression system, wherein the centrifugal blades include large centrifugal blades, small centrifugal blades and a centrifugal wheel. The large centrifugal blades and the small centrifugal blades are evenly and alternately arranged circumferentially on the centrifugal wheel. The length of the large centrifugal blades is greater than that of the small centrifugal blades, and the tails of the large centrifugal blades and the small centrifugal blades are flush.

[0006] The centrifugal compressor suitable for a mixed flow compression system, the diffuser section includes a diffuser section inner wall, blades and a diffuser section end cover, the diffuser section inner wall and the diffuser section end cover are connected by assembly bolts, the diffuser section inner wall is connected to the blades to form a blade diffuser in the diffuser section.

[0007] The centrifugal compressor suitable for a mixed flow compression system, the outlet guide vane assembly comprises an outlet guide vane and a root top end wall, and the outlet guide vane is welded to the root top end wall.

[0008] In the centrifugal compressor suitable for a mixed flow compression system, the wheel back of the centrifugal wheel disc and the blade back sealing body form a sealing channel.

[0009] The centrifugal compressor suitable for a mixed flow compression system has through holes on the centrifugal wheel.

[0010] The centrifugal compressor suitable for a mixed flow compression system, the centrifugal impeller 1 and the impeller end cover are gap-matched to form an airflow channel, the impeller end cover matching surface contour line is consistent with the centrifugal impeller tip line, and the gap d of the matching surface is 0.3mm-0.5mm. Beneficial Effects

[0011] 1. The present invention provides a centrifugal compressor for a mixed flow compression system, which enriches the types of small and medium flow engines and gas turbine compressors. The centrifugal compressor structure can solve the leakage problem of high pressure airflow at the blade outlet and improve the compressor efficiency.

[0012] 2. The present invention introduces air into the axial compressor part through the through hole on the centrifugal impeller and into the back of the centrifugal impeller, which can help control the axial force of the centrifugal compressor.

[0013] 3. The present invention has the advantages of simple structure, ingenious design, convenient processing, low cost, and is suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the structure of a centrifugal impeller; Figure 3 yes Figure 1 Enlarged view of part C; Figure 4 It is a schematic diagram of centrifugal impeller assembly; Figure 5 It is a schematic diagram of the structure of the diffuser section; Figure 6 yes Figure 5 BB section view; Figure 7 is a schematic diagram of the structure of the outlet guide vane assembly; Figure 8 yes Figure 7 AA section view; Fig. 9 It is a schematic diagram of the sealing structure of the wheel back and the blade back sealing body of the centrifugal impeller; Fig.10 It is a schematic diagram of the assembly structure of the present invention and the axial flow compressor; In the figure: A, axial flow compressor; B, centrifugal compressor; 1, centrifugal impeller; 2, impeller cover; 3, centrifugal compressor casing; 4, diffuser section; 5, outlet guide vane assembly; 6, back seal; 11, centrifugal large blades; 12, centrifugal small blades; 13, centrifugal impeller; 14, through hole; 21, annular sealing teeth; 22, circular protrusion; 31, axial flow compressor last stage wheel; 41, blades; 42, diffuser section inner wall; 43, diffuser section end cover; 44, bolts; 51, outlet guide vanes; 52, end wall. DETAILED DESCRIPTION

[0015] Reference Figure 1-Figure 10 , a centrifugal compressor suitable for a mixed flow compression system, used for compressing the air of an upstream axial flow compressor to reach the air pressure required by a combustion chamber, provides a centrifugal compressor for a mixed flow compression system, has the advantages of high pressure ratio, high efficiency, large flow rate, simple structure, etc., solves the problem that the height of the last stage blades is too small and the efficiency is too low as the pressure ratio of the axial flow compressor of a small and medium flow engine and a gas turbine increases, and enriches the structure of the centrifugal compressor of the mixed flow compression system, including a centrifugal impeller 1, an impeller end cover 2, a centrifugal compressor casing 3, a diffuser section 4, an outlet guide vane assembly 5 and a blade back seal 6; The centrifugal impeller 1 is a rotating component, and the impeller end cover 2 is a stationary component; The centrifugal impeller and the impeller end cover cooperate to form an air flow channel; the diffuser section 4 is located above the centrifugal impeller outlet, and a blade diffuser is provided in the diffuser section for reducing the air flow rate and increasing the air static pressure; the outlet guide vane assembly is provided with guide vanes for the air flow to flow out radially; The centrifugal impeller 1 is clearance-matched with the impeller end cover 2, and the impeller end cover is fixed to the centrifugal compressor casing by bolts; A diffuser section is fixed above the centrifugal impeller outlet by bolts, and the outlet side of the diffuser section is fixed to the outlet guide vane assembly.

[0016] The centrifugal blades include a large centrifugal blade 11, a small centrifugal blade 12 and a centrifugal wheel 13. The large centrifugal blades, the small centrifugal blades and the centrifugal wheel are integrally forged and made of titanium alloy. The large centrifugal blades 11 and the small centrifugal blades 12 are evenly and alternately arranged circumferentially on the centrifugal wheel 1. The length of the large centrifugal blades 11 is greater than the length of the small centrifugal blades 12, and the tails of the large centrifugal blades 11 and the small centrifugal blades 12 are flush. The roots of the large centrifugal blades 11 and the small centrifugal blades 12 are both chamfered. The leading and trailing edges of the centrifugal large blades and the centrifugal small blades are both elliptical structures, which, combined with air flow mechanics, is conducive to the rotation of the impeller.

[0017] By arranging the large centrifugal blades and the small centrifugal blades to match each other, an air passage is formed between each large centrifugal blade and the small centrifugal blade, which can delay the formation of separation at the outer end of the blade and reduce the size of the separation zone, thereby reducing gas flow losses and improving the working efficiency of the compressor; at the same time, the length of the large centrifugal blade 11 is greater than the length of the small centrifugal blade 12, which can effectively improve the intake efficiency of the compressor and ensure the intake quality of the intake airflow, effectively prevent the engine from surging and increase the working margin of the engine.

[0018] The diffuser section includes a diffuser section inner wall 42, blades 41 and a diffuser section end cover 43. The diffuser section inner wall 42 and the diffuser section end cover 43 are connected by assembly bolts 44. The diffuser section inner wall 42 is connected to the blades 41 to form a blade diffuser in the diffuser section. The assembly bolts have smooth surfaces on the inner arc and back arc of the blades, which can reduce airflow losses. The sealing body between the impeller cover and the centrifugal compressor casing includes a plurality of annular sealing tooth structures 21 of different diameters, which cooperate with the circular protrusions 22 on the outer surface of the impeller cover to prevent the high-pressure airflow at the impeller outlet from flowing to the impeller inlet; The outlet guide vane assembly comprises an outlet guide vane and a root top end wall, and the outlet guide vane 51 is welded to the root top end wall 52 .

[0019] The wheel back 6 of the centrifugal impeller and the blade back seal form a sealing channel to prevent high-pressure gas from flowing back to the centrifugal compressor inlet along the blade back and the wheel cover. The centrifugal compressor draws air from the axial compressor part and introduces it into the back of the centrifugal impeller through the through hole 14 on the centrifugal impeller, which can help control the axial force of the centrifugal compressor. At the same time, the sealing channel is composed of multiple groups of labyrinth gas sealing teeth. The high-pressure gas passes through the sealing channel, which can effectively reduce the leakage of the high-pressure gas at the impeller outlet. At the same time, the impeller outlet pressure is gradually reduced in the radial direction, which is also helpful to reduce the axial force of the impeller. In addition, the labyrinth gas sealing teeth are arranged in multiple groups. While achieving the sealing effect, it softens the airflow pressure, enhances the sealing effect, and prolongs the service life, which helps to solve the problem of large axial force on the compressor impeller in the prior art. The centrifugal impeller is connected to the final impeller 31 of the axial flow compressor via a flange, so that the centrifugal impeller and the axial flow compressor run at the same speed; The centrifugal wheel disc is provided with a through hole.

[0020] The centrifugal impeller 1 and the impeller end cover 2 are clearance-matched to form an airflow channel. The contour line of the impeller end cover matching profile is consistent with the tip profile of the centrifugal impeller. The clearance d of the matching surface is 0.3mm-0.5mm, which avoids unnecessary friction loss and improves service life.

Claims

1. A centrifugal compressor suitable for a mixed flow compression system, characterized in that: It includes a centrifugal impeller, an impeller cover, a centrifugal compressor casing, a diffuser section, an outlet guide vane assembly and a blade back seal; The centrifugal impeller and the impeller end cover are clearance-matched, and the impeller end cover and the centrifugal compressor casing are fixed by bolts; A diffuser section is fixed above the centrifugal impeller outlet by bolts, and the outlet side of the diffuser section is fixed to the outlet guide vane assembly.

2. A centrifugal compressor suitable for a mixed flow compression system according to claim 1, characterized in that: The centrifugal blades include large centrifugal blades, small centrifugal blades and a centrifugal wheel. The large centrifugal blades and small centrifugal blades are evenly and alternately arranged circumferentially on the centrifugal wheel. The length of the large centrifugal blades is greater than that of the small centrifugal blades, and the tails of the large centrifugal blades and the small centrifugal blades are flush.

3. A centrifugal compressor suitable for a mixed flow compression system according to claim 1, characterized in that: The diffuser section includes an inner wall of the diffuser section, blades and an end cover of the diffuser section. The inner wall of the diffuser section and the end cover of the diffuser section are connected by assembly bolts. The inner wall of the diffuser section is connected to the blades to form a blade diffuser in the diffuser section.

4. The centrifugal compressor suitable for a mixed flow compression system according to claim 1, characterized in that: The outlet guide vane assembly comprises an outlet guide vane and a root top end wall, and the outlet guide vane is welded to the root top end wall.

5. The centrifugal compressor suitable for a mixed flow compression system according to claim 1, characterized in that: The wheel back of the centrifugal wheel disc and the blade back sealing body form a sealing channel.

6. A centrifugal compressor suitable for a mixed flow compression system according to claim 5, characterized in that: The centrifugal wheel disc is provided with a through hole.

7. The centrifugal compressor suitable for a mixed flow compression system according to claim 1, characterized in that: The centrifugal impeller 1 and the impeller end cover are gap-matched to form an airflow channel. The contour line of the matching profile of the impeller end cover is consistent with the tip profile of the centrifugal impeller, and the gap d of the matching surface is 0.3mm-0.5mm.

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