Expanding the choke margin of a mixed flow compressor stage for a micro gas turbine engine

Eck, Hano van; Spuy, Sybrand J. van der; Gannon, Anthony J.

doi:10.1515/tjj-2022-0060

Cited by 3 publications

(8 citation statements)

References 9 publications

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“…To expand the operating range of the upgraded CAT250TJ_BL compressor, selected operating range expansion methods discussed in Van Eck [15] are employed. These are discussed below.…”

Section: Baseline Test Compressor Designmentioning

confidence: 99%

“…3) allows the boundary layer to be re-energised, better controlling the boundary layer at various operating points and therefore the overall operating range. Van Eck [15] numerically investigated various tandem vane crossover diffuser configurations and their effect on compressor design point performance and operating range. It was shown that a low solidity front vane configuration displayed a marked increase in choke margin.…”

Section: Introductionmentioning

confidence: 99%

“…A 70-75 configuration provided superior exit tangential velocity results. The designation 70-75 refers to a tandem vane diffuser having a front vane length 70% relative to the total diffuser vaned [12] length and a second vane relative tangential shift of 75% [15].…”

Section: Introductionmentioning

confidence: 99%

“…Van Eck et al [16] evaluated methods to increase the choke margin of a mixed flow compressor fitted with a crossover diffuser. Various splitter vaned, tandem vaned and combinations of these were presented and these provided a marked increase in choke margin.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to note that the current study forms part of a larger PhD study [15] evaluating the effect of various crossover diffuser configurations on the performance of the compressor stage of an MGT engine. The current paper is in fact the culmination of this study, where the findings of the larger study is tested on a real-world application, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Upgrading the Compressor Stage of the CAT250TJ Micro Gas Turbine Engine

van Eck,

van der Spuy

2024

Aerotec. Missili Spaz.

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Due to their simplicity and relative ease of manufacture, single-stage centrifugal and mixed flow micro gas turbine (MGT) engines are preferred in thrust-based remotely piloted aerial vehicles. A single-stage mixed-flow compressor upgrade for the 200 N CAT250TJ MGT engine is numerically evaluated and presented. An in-house developed mean line application and commercial CFD software is used for the design and performance evaluation of the proposed upgrade configurations. The CAT250TJ – Gen1 engine features a single-stage centrifugal compressor, annular combustor, and single stage axial turbine. Apart from an upgraded impeller, a new crossover diffuser configuration is introduced to replace the wedge-type, straight outlet diffuser configuration of the Gen1 engine. The new single vane crossover diffuser configuration provides a design point total-to-total efficiency and pressure ratio increase of 8.3% and 12.1%, respectively. A disadvantage of a single-vaned crossover diffuser compared to legacy diffusers is a narrower operating range. To alleviate this issue, various combinations of tandem and splitter vane crossover diffuser configurations are proposed. These provide an enhanced operating range, comparable with the operating range displayed by the Gen1 configuration. A turbine power matching analysis is additionally completed to ensure proper compressor integration. Gas turbine cycle software is used to evaluate the on-engine performance of the upgraded compressor configurations. It is shown that the new baseline, single vane crossover diffuser configuration provides a 10.74% increase in design point static thrust.

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“…To expand the operating range of the upgraded CAT250TJ_BL compressor, selected operating range expansion methods discussed in Van Eck [15] are employed. These are discussed below.…”

Section: Baseline Test Compressor Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Upgrading the Compressor Stage of the CAT250TJ Micro Gas Turbine Engine

van Eck,

van der Spuy

2024

Aerotec. Missili Spaz.

Self Cite

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Investigating the mechanism of flow of transonic compact crossover tandem diffuser

Zhang,

Huang

et al. 2024

Physics of Fluids

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Dealing with high transonic airflow at the outlet of a mixed-flow impeller is a challenging issue in research on the design of efficient and compact diffusers. A low aspect ratio and an adverse pressure gradient in the passage of the diffuser can lead to flow separation on the hub side of the bend and the suction side of the aft blade. Tandem blading can be used to attain flow control through an appropriate relative circumferential tandem position (λ). However, a comprehensive understanding of flow in a compact crossover tandem diffuser (CTD) requires further investigation. This study provides a detailed analysis of the mechanism of flow in a compact crossover baseline tandem diffuser (CBTD) as well as the influence of different values of λ on the structure of flow of the CTD. The findings show that the CBTD can suppress secondary flow separation on the hub side of the bend by reasonably distributing the radial load. We also found that a value of λ of 75% can delay the point of separation on the suction side of the aft blade over a wide range of spans, where this inhibits the corner separation vortex and improves the structure of flow and performance of the diffuser. We also preliminarily explore the impacts of excitation of full-span jet intensities with different values of λ on the corner separation vortex on the suction side of the aft blade and offer guidance for the design of a compact and efficient CTD.

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Upgraded one-dimensional code for the design of a micro gas turbine mixed flow compressor stage with various crossover diffuser configurations

van Eck,

van der Spuy

2024

International Journal of Turbo &Amp; Jet-Engines

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Micro Gas Turbine (MGT) designers often have the need for a design tool, capable of rapidly providing feasible design options. The upgrade of such an existing MATLAB® based mixed flow compressor design application (1D App) is discussed. In MGT engines, diffuser design largely influences the compressor stage performance. Crossover diffusers provide superior efficiency and pressure ratio performance compared to legacy type diffusers, albeit at the expense of operating range. The reduced operating range attributed to single vane crossover diffusers can be alleviated by splitter vane, tandem vane, and combined configurations. Therefore, the 1D App is updated to allow the user the ability to design these additional crossover diffuser configurations. Performance results are verified using Numeca/FINE™ Turbo CFD software. It is shown that the upgraded 1D App provides predicted performance results within 1 % of CFD results for both total-to-total efficiency and pressure ratio.

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Expanding the choke margin of a mixed flow compressor stage for a micro gas turbine engine

Cited by 3 publications

References 9 publications

Upgrading the Compressor Stage of the CAT250TJ Micro Gas Turbine Engine

Upgrading the Compressor Stage of the CAT250TJ Micro Gas Turbine Engine

Investigating the mechanism of flow of transonic compact crossover tandem diffuser

Upgraded one-dimensional code for the design of a micro gas turbine mixed flow compressor stage with various crossover diffuser configurations

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