CN-121997551-A - Centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis

CN121997551ACN 121997551 ACN121997551 ACN 121997551ACN-121997551-A

Abstract

The invention provides a centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis, which comprises the steps of constructing a computational fluid dynamics simulation model of a centrifugal compressor impeller, obtaining unsteady pressure load data of the surface of the impeller through the computational fluid dynamics simulation model, mapping the unsteady pressure load data to a structural field of the impeller, establishing fluid structure coupling data association, constructing a solid structure simulation model of the centrifugal compressor impeller, calculating impeller stress distribution data under the coupling effect of centrifugal load and pneumatic pressure load based on the fluid structure coupling data association, determining a fatigue crack initiation area of the impeller based on a fatigue strength theory according to the impeller stress distribution data, carrying out shot peening strengthening process optimization design on the fatigue crack initiation area, and realizing improvement of fatigue resistance of the impeller by regulating shot peening process parameters. The method accurately predicts the fatigue crack initiation area of the impeller, carries out accurate strengthening on the key area, and ensures the reliability and the effectiveness of the fatigue strengthening process.

Inventors

XIANG JIAN
JIANG LIJUN
TAN JIANGFENG
HOU HAICHEN
Jiang Anhuan
LIU JING

Assignees

重庆通用工业(集团)有限责任公司

Dates

Publication Date: 20260508
Application Date: 20251224

Claims (8)

1. A centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis is characterized by comprising the following steps: S001, constructing a computational fluid dynamics simulation model of the centrifugal compressor impeller, and acquiring unsteady pressure load data of the surface of the blade through the computational fluid dynamics simulation model; step S002, mapping the unsteady pressure load data to a structural field of an impeller to obtain pneumatic pressure load, and establishing fluid structure coupling data association; Step S003, a solid structure simulation model of the centrifugal compressor impeller is constructed, and impeller stress distribution data under the coupling action of centrifugal load and pneumatic pressure load are calculated based on the coupling data association of the fluid structure; Step S004, determining a fatigue crack initiation area of the impeller based on a fatigue strength theory according to the impeller stress distribution data; And S005, performing shot peening strengthening process optimization design on the fatigue crack initiation area, and improving the fatigue resistance of the impeller by regulating and controlling shot peening process parameters.
2. The method for fatigue reinforcement of centrifugal compressor impeller based on multi-field coupling analysis according to claim 1, wherein the step S001 comprises: Constructing a three-dimensional geometric model of the impeller fluid domain; setting calculation parameters including rotation speed, flow rate, inlet pressure and inlet temperature according to the design working condition of the impeller; performing unstructured grid division on the three-dimensional geometric model of the impeller fluid domain, and arranging boundary layer grids on the wall surfaces of the blades and the flow channels to obtain a first grid model; And based on the first grid model, calculating a steady state and an unsteady flow field according to the calculation parameters, and extracting pressure values of each discrete node on the surface of the blade under different time steps to obtain unsteady pressure load data.
3. The method for fatigue reinforcement of centrifugal compressor impeller based on multi-field coupling analysis according to claim 1, wherein the step S002 comprises: And mapping the unsteady pressure load data to a structural field of the impeller through a linear interpolation technology to obtain pneumatic pressure load, and establishing fluid structural coupling data association.
4. The method for fatigue reinforcement of a centrifugal compressor impeller based on multi-field coupling analysis according to claim 1, wherein the constructing a solid structure simulation model of the centrifugal compressor impeller comprises: establishing an impeller three-dimensional solid geometric model; setting mechanical property parameters of impeller materials; Carrying out structural grid division on the impeller three-dimensional solid geometric model, and carrying out grid refinement on the root area of the blade to obtain a second grid model; And setting a fixed constraint condition to apply the pneumatic pressure load, and obtaining a solid structure simulation model based on the second grid model.
5. The method for strengthening fatigue of an impeller of a centrifugal compressor based on multi-field coupling analysis according to claim 1, wherein calculating impeller stress distribution data under coupling effect of centrifugal load and pneumatic load based on the coupling data of the fluid structure comprises: And calculating dynamic stress response of the impeller based on the solid structure simulation model by adopting a transient dynamics finite element method to obtain a maximum dynamic stress distribution curve on the blade and the hub, and obtaining impeller stress distribution data.
6. The method for fatigue reinforcement of centrifugal compressor impeller based on multi-field coupling analysis according to claim 1, wherein the step S004 comprises: processing the impeller stress distribution data based on a rain flow counting method, and extracting the mean value and the amplitude of stress circulation; acquiring an S-N curve of an impeller material; Based on a Michenna linear accumulated damage theory, fatigue damage of each part of the impeller is calculated according to the mean value and the amplitude of the stress cycle and the S-N curve, and a region with the damage accumulated value exceeding a preset threshold is identified as a fatigue crack initiation region.
7. The method for strengthening fatigue of a centrifugal compressor impeller based on multi-field coupling analysis according to claim 1, wherein the optimization design of the shot peening process for the fatigue crack initiation area comprises: And optimizing and determining at least one technological parameter of a shot blasting area, a shot diameter, a shot blasting speed and a shot blasting angle according to the position of the fatigue crack initiation key area and the impeller stress distribution data.
8. The method of claim 6, wherein the step of obtaining an S-N curve of the impeller material comprises: The S-N curve is obtained through least square fitting, and the fitting equation is as follows: lgN=blgS+a Where N represents lifetime, S represents stress, and a and b represent fitting parameters.

Description

Centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis Technical Field The invention relates to the technical field of centrifugal compressor blade optimization design, in particular to a centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis. Background The centrifugal compressor has become a core device in the fields of petrochemical industry, natural gas, coal chemical industry and the like by virtue of the remarkable advantages of high single-stage pressure ratio, wide working condition range, compact structure and the like. The high-efficiency gas compression capacity and the compact mechanical structure of the device can keep stable operation under severe working conditions such as high temperature, high pressure, high load and the like, and the device becomes an indispensable key power device in modern industrial processes. The impeller is used as a core component of the centrifugal compressor, and the performance of the impeller directly determines the efficiency and reliability of the whole machine. However, under the complex working condition, the impeller is required to bear the long-term action of steady-state loads such as centrifugal force, thermal load and the like, and also is required to cope with the fluid exciting force generated by the unsteady flow field. The exciting force is generated by dynamic phenomena such as gas vortex, separation, reattachment and the like in a flow field, so that transient and alternating stress distribution is generated on the surface of the blade. When such alternating stresses exceed the fatigue limit of the material, microcracks may develop on the blade surface or inside, thereby initiating fatigue failure. The Chinese patent application publication No. CN 116127653A discloses a shape optimization design method for improving the fatigue strength of a blade, the blade and a centrifugal impeller, and the core flow comprises the steps of precisely positioning the initiation position of the fatigue crack of the blade through a high-cycle fatigue test, further identifying key areas in the manufacture of the impeller, then adjusting the edge fillet structure of the key areas, designing a surface microscopic morphology forming process, and simultaneously assisting in the shot blasting strengthening treatment of microparticles so as to remarkably improve the fatigue strength of the key areas. However, the high-cycle fatigue test method relied on by the patent has the remarkable limitations that the test cost is high, the period is long, the engineering requirement of quick iteration is difficult to meet, and the multi-field coupling effect (such as interaction of pneumatic load, thermal stress and mechanical vibration) under the actual working condition cannot be comprehensively simulated, so that the identification precision of a key area is limited, and the pertinence and the reliability of the optimal design are further affected. Disclosure of Invention In view of the foregoing, it is desirable to provide a method for fatigue reinforcement of centrifugal compressor impellers based on multi-field coupling analysis. A centrifugal compressor impeller fatigue strengthening method based on multi-field coupling analysis comprises the following steps: S001, constructing a computational fluid dynamics simulation model of the centrifugal compressor impeller, and acquiring unsteady pressure load data of the surface of the blade through the computational fluid dynamics simulation model; step S002, mapping the unsteady pressure load data to a structural field of an impeller to obtain pneumatic pressure load, and establishing fluid structure coupling data association; Step S003, a solid structure simulation model of the centrifugal compressor impeller is constructed, and impeller stress distribution data under the coupling action of centrifugal load and pneumatic pressure load are calculated based on the coupling data association of the fluid structure; Step S004, determining a fatigue crack initiation area of the impeller based on a fatigue strength theory according to the impeller stress distribution data; And S005, performing shot peening strengthening process optimization design on the fatigue crack initiation area, and improving the fatigue resistance of the impeller by regulating and controlling shot peening process parameters. In one embodiment, step S001 includes: Constructing a three-dimensional geometric model of the impeller fluid domain; setting calculation parameters including rotation speed, flow rate, inlet pressure and inlet temperature according to the design working condition of the impeller; performing unstructured grid division on the three-dimensional geometric model of the impeller fluid domain, and arranging boundary layer grids on the wall surfaces of the blades and the flow channels to obtain a first grid model; And based on the first grid model, calculating a s