Abstract
In an attempt to reduce engine frontal area, while maintaining a high single stage pressure ratio, mixed flow compressor stages are frequently used in micro gas turbine (MGT) engines. The expansion of the choke margin of such a mixed flow compressor is presented. The use of a crossover diffuser configuration in a mixed flow compressor stage has displayed superior performance results compared to legacy diffuser configurations, especially when geometric restrictions are enforced. A disadvantage of a crossover diffuser configuration is that it typically displays an inferior operating range compared to legacy diffuser configurations. In an attempt to expand the choke margin of a MGT mixed flow compressor, the use of tandem and splitter vane crossover diffuser configurations was evaluated. It was found that a low solidity first vane row configuration provided a 3% increase in choke margin. A splitter vane crossover diffuser configuration provided a 5.9% increase in choke margin. A tandem vaned diffuser with a reduced first row vane number provided a 7.8% increase in choke margin.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: None declared.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
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