CN-116085303-B - Centrifugal compressor closed type runoff impeller blade tip clearance flow loss inhibition structure

Abstract

The invention discloses a closed type radial flow impeller top clearance flow loss inhibition structure of a centrifugal compressor, wherein a top clearance and a wheel cover seal for reducing air leakage of the top clearance are arranged between a closed type radial flow impeller and a shell of the centrifugal compressor, the closed type radial flow impeller comprises a wheel cover, a wheel disc and a plurality of blades, the blades are arranged between the wheel cover and the wheel disc at intervals along the circumferential direction, the centrifugal compressor further comprises the wheel cover seal, first grooves with geometric shapes are arranged on the circumferential direction of the inner wall of the wheel cover and between the adjacent blades, and first protrusions with the same shape as the first grooves are arranged on the outer wall of the wheel cover corresponding to the first grooves. The invention can effectively reduce the airflow kinetic energy of the clearance flow at the top of the blade and reduce the steam leakage, thereby effectively inhibiting the loss of the clearance flow at the top of the blade.

Inventors

• ZHONG ZHUHAI
• YANG CHANGZHU
• CHEN HONGFEN
• WEI YAN
• FAN XIAOPING
• SUN QI
• HOU MINGJUN
• TIAN CHAOYANG
• ZHU YING

Assignees

• 东方电气集团东方汽轮机有限公司

Dates

Publication Date

20260512

Application Date

20221128

Claims (5)

1. 1. A closed type radial flow impeller blade tip clearance flow loss restraining structure of a centrifugal compressor is characterized in that a blade tip clearance (11) and a wheel cap seal (3) for reducing air leakage of the blade tip clearance (11) are arranged between a closed type radial flow impeller (2) and a shell (1) of the centrifugal compressor, the closed type radial flow impeller (2) comprises a wheel cap (21), a wheel disc (22) and a plurality of blades (23), the blades (23) are arranged between the wheel cap (21) and the wheel disc (22) at intervals in the circumferential direction, first grooves (211) with geometric shapes are formed in the circumferential direction of the inner wall of the wheel cap (21) between the adjacent blades (23), and first protrusions (212) with the same shape as the first grooves (211) are arranged on the outer wall of the wheel cap (21) corresponding to the first grooves (211).
2. 2. The closed radial flow impeller tip clearance flow loss suppressing structure of a centrifugal compressor according to claim 1, wherein said first grooves (211) are plural in the axial direction, and correspondingly said first protrusions (212) are plural in the axial direction.
3. 3. The closed radial flow impeller tip clearance flow loss suppressing structure for a centrifugal compressor according to claim 1 or 2, wherein the first grooves (211) are regular hexagons, and the first protrusions (212) are regular hexagons, respectively.
4. 4. The closed radial flow impeller tip clearance flow loss suppression structure of the centrifugal compressor according to claim 1, wherein one end of the shroud (21) matched with the shroud seal (3) is of a stepped structure which gradually rises from left to right in the axial direction, and the shroud seal (3) is provided with a seal tooth (31) matched with the stepped structure corresponding to each step.
5. 5. The structure for suppressing the loss of a shrouded radial flow impeller tip clearance flow of a centrifugal compressor as set forth in claim 1, wherein the shroud seal (3) is provided with a plurality of second protrusions (32) at intervals corresponding to the circumference of one side of the tip clearance flow entering direction, and second grooves (33) are formed between adjacent second protrusions (32).

Description

Centrifugal compressor closed type runoff impeller blade tip clearance flow loss inhibition structure Technical Field The invention relates to the technical field of radial flow impellers, in particular to a closed radial flow impeller blade tip clearance flow loss suppression structure of a centrifugal compressor. Background In recent years, radial flow impellers are widely used in industrial production with low power level due to the characteristics of simple structure and manufacturing process, convenient installation, small volume and the like. Radial flow impellers typically have three configurations, closed, semi-open, and open. Such as closed-flow impellers for centrifugal compressors. The closed radial flow impeller is arranged in the shell and has relative motion, a gap is needed to exist between the dynamic component and the static component, and the gap structure enables working medium in the centrifugal compressor to generate blade top gap flow loss, so that steam leakage loss is caused, and the efficiency of the unit is affected. The existing research on the leakage of the clearance between the blade tips is focused on the axial-flow impeller, the flow field structure in the closed-type radial-flow impeller is relatively complex, the influence of the leakage flow of the clearance between the blade tips on the mechanical property of the impeller is more serious, and the leakage steam loss control technology aiming at the axial-flow impeller cannot be well applied to the closed-type radial-flow impeller. At present, main technical means for reducing/inhibiting the clearance flow loss of the blade tip comprise reducing the clearance size of the dynamic and static components, mounting and sealing, and the like, and the clearance size of the dynamic and static components cannot be too small in practical application in consideration of the safety of the unit. The common seal is an inner seal and an outer seal. The inner seal is used for preventing gas from flowing backwards between stages, such as a shroud seal at the shroud, but the gas still has higher flow speed when flowing out of the impeller, and the problem of higher loss of clearance flow at the top of the blade still exists when the single seal structure is adopted in actual use. Therefore, the reasonable structure is adopted to reduce the steam leakage loss and improve the safety and the economical efficiency of the unit aiming at the structural characteristics of the closed radial flow impeller. Disclosure of Invention The invention aims to provide a closed radial flow impeller blade tip clearance flow loss restraining structure of a centrifugal compressor, which has good sealing effect and can slow down the flow speed of the blade tip clearance flow. The technical problems to be solved by the invention are realized by the following technical scheme: A closed type radial flow impeller blade tip clearance flow loss restraining structure of a centrifugal compressor is characterized in that a blade tip clearance and a shroud seal for reducing air leakage of the blade tip clearance are arranged between a closed type radial flow impeller and a shell of the centrifugal compressor, the closed type radial flow impeller comprises a shroud, a wheel disc and a plurality of blades, the blades are arranged between the shroud and the wheel disc at intervals along the circumferential direction, the centrifugal compressor further comprises the shroud seal, first grooves with geometric shapes are formed in the circumferential direction of the inner wall of the shroud and between adjacent blades, and first protrusions with the same shape as the first grooves are arranged on the outer wall of the shroud corresponding to the first grooves. The first grooves are plural in the axial direction, and correspondingly, the first protrusions are plural in the axial direction. The first grooves are regular hexagons, and correspondingly, the first protrusions are regular hexagons. One end of the wheel cover, which is matched with the wheel cover in a sealing way, is of a stepped structure which gradually rises from left to right in the axial direction, and sealing teeth matched with the wheel cover are arranged on the wheel cover in a sealing way corresponding to each step. The wheel cover seals, a plurality of second bulges are arranged at intervals corresponding to the circumference of one side of the entering direction of the clearance flow of the blade top, and second grooves are formed between every two adjacent second bulges. Compared with the prior art, the invention has the beneficial effects that: 1. the inner wall of the wheel cover is provided with the regular hexagon first grooves between the adjacent blades, namely a plurality of regular hexagon first grooves are uniformly arranged on the inner wall of the wheel cover at intervals along the flowing direction and the circumferential direction corresponding to the air passages. By arranging the first groove