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International Standard Serial Number:
ISSN 1001-4551
Sponsor:
Zhejiang University;
Zhejiang Machinery and Electrical Group
Edited by:
Editorial of Journal of Mechanical & Electrical Engineering
Chief Editor:
ZHAO Qun
Vice Chief Editor:
TANG ren-zhong,
LUO Xiang-yang
Tel:
86-571-87041360,87239525
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86-571-87239571
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No.9 Gaoguannong,Daxue Road,Hangzhou,China
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Abstract: To clarify the mechanism of the influence of tip clearance on the performance of centrifugal compressors, numerical simulation methods were used to study the effects of leakage vortices and flow losses at the centrifugal compressors under different tip clearances. Firstly, the reliability of the simulation was verified by comparing the experimental results with the numerical calculation results. Then, the changing trends of isentropic efficiency and pressure ratio of the compressor under different tip clearances were analyzed. Finally, the internal flow characteristics were analyzed, and under different clearances, the changes in the vortex structure inside the impeller, the distribution of leakage flow streamlines, and the entropy change law along the flow direction were elaborated. The mechanism of different tip clearances' effect on compressor performance was investigated. The research results indicate that when the tip clearance ratio increases from 0.018 to 0.054, the maximum changes in efficiency decrease across the entire operating range are 0.7%, 0.6%, 0.4%, and 0.2% respectively. The overall decrease in pressure ratio remains around 0.3%. The tip leakage flow is mixed with the mainstream to form tip leakage vortices and tip separation vortices, among which tip leakage vortices are the main source of loss. As the tip clearance ratio increases, the flow loss within the 20% flow direction range near the leading edge of the blade changes less, while the loss increases within the 40% range near the trailing edge of the blade. The increase in the tip clearance ratio leads to an increase in the size of the leakage vortex, thereby reducing the effective flow area, which is the main reason for the performance degradation of the compressor.
Key words: gas compressor; centrifugal compressor; entropy change law; numerical simulation method; compressor aerodynamic performance; leakage vortex; flow loss;internal flow characteristics
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2010 Zhejiang Information Institute of Mechinery Industry
Technical Support：Hangzhou Bory science and technology
