Improving the quality of design calculations of viscous flow in low-flow centrifugal compressor stages by methods of computational fluid dynamics through reasonable application of different turbulence models
The paper considers the issue of improving the quality of the numerical experiment in the calculation of viscous gas in the flowing part of a low-flow centrifugal compressor stage. The choice of turbulence model in creating a calculation model for calculations by methods of computational fluid...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Omsk State Technical University, Federal State Autonoumos Educational Institution of Higher Education
2021-04-01
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| Series: | Омский научный вестник |
| Subjects: | |
| Online Access: | https://www.omgtu.ru/general_information/media_omgtu/journal_of_omsk_research_journal/files/arhiv/2021/%E2%84%96%202%20(176)%20(%D0%9E%D0%9D%D0%92)/24-30%20%D0%9A%D0%B0%D1%80%D1%82%D0%B0%D1%88%D0%BE%D0%B2%20%D0%A1.%20%D0%92.,%20%D0%9A%D0%BE%D0%B6%D1%83%D1%85%D0%BE%D0%B2%20%D0%AE.%20%D0%92..pdf |
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| Summary: | The paper considers the issue of improving the quality of
the numerical experiment in the calculation of viscous gas
in the flowing part of a low-flow centrifugal compressor
stage. The choice of turbulence model in creating
a calculation model for calculations by methods of
computational fluid dynamics is substantiated. As object
of research is chosen low-flow stage with conditional flow
coefficient Ф=0,008 and relative width at impeller outlet
b2
/D2
=0,0133. The issue of qualitative modeling of friction
losses in low-flow stages is of fundamental importance and
is directly related to the choice of turbulence model. It is
shown that the choice of low-Reynolds turbulence models
in the case of unloaded and discontinuous low-flow stages
can be made from the main common models (SpalartAllmaras, SST, k-ω) based on the economy of calculations,
speed of convergence, solution stability and adequacy
of the obtained results. For models with wall functions,
the quality of the mesh model and the observance of the
dimensionless distance to the wall y+ throughout the
calculation domain are particularly important. For highReynolds turbulence models, at values of y+=25...50 on
all friction surfaces of the computational domain in the
optimal mode of operation, the grid independence of
the solution for the entire gas-dynamic characteristic is
ensured. It is unacceptable for y+ to fall into the transition region of 4...15 between the viscous sublayer and the
region of the logarithmic velocity profile. |
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| ISSN: | 1813-8225 2541-7541 |