Demonstration of a Semi-Closed Cycle, Turboshaft Gas Turbine Engine

Meitner, Peter L.; Laganelli, A. L.; Senick, Paul F.; Lear, W. E.

doi:10.1115/2000-gt-0535

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…The recirculation ratio of the first can be better adjusted to keep the high pressure components close to their peak efficiency, as also shown in Ref. (7). This is only partially achievable with the Coleman cycle arrangement as less feedback flow rate is available and sufficient power has to be extracted from the LPT.…”

Section: Resultsmentioning

confidence: 92%

“…Ref. (7) has shown that the HPRTE arrangement presents a much flatter SFC curve at part-power off-design operating points with respect to conventional configuration. This aspect has been confirmed by this analysis as well.…”

Section: Resultsmentioning

confidence: 99%

“…More recent research on semi-closed cycles, performed under the HPRTE (High Pressure Regenerative Turbine Engine) program (6,7) , has underlined the following main set of advantages over a conventional ICR configuration: Lower inlet mass flow As a consequence of the recirculated gases, the amount of inlet fresh air has to be sufficient only to ensure combustion. In this way, the ratio of fresh air to fuel mass flow is almost stoichiometric, even though the reaction temperature is reduced by the recirculated products. Engine compactness The optimal overall pressure ratio (OPR) is far higher in semi-closed cycles than in equivalent open cycle solutions.…”

Section: Introductionmentioning

confidence: 99%

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Multi-objective optimisation of semi-closed cycle engines for high-altitude UAV propulsion

2019

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The maximum attainable performance of small gas turbines represents a strong limitation to the operating altitude and endurance of high-altitude unmanned aerial vehicles (UAVs). Significant improvement of the cycle thermal efficiency can be achieved through the introduction of heat exchangers, with the consequent increase of the overall engine weight. Since semi-closed cycle engines can achieve a superior degree of compactness compared to their open cycle counterparts, their use can offset the additional weight of the heat exchangers. This paper applies semi-closed cycles to a high-altitude UAV propulsion system, with the objective of assessing the benefits introduced on the engine performance and weight. A detailed model has been created to account for component performance and size variation as function of thermodynamic parameters. The sizing has been coupled with a multi-objective optimisation algorithm for minimum specific fuel consumption and weight. Results of two different semi-closed cycle configurations are compared with equivalent state-of-the-art open cycles, represented by a recuperated and an intercooled-recuperated engine. The results show that, for a fixed design power output, engine weight is approximately halved compared to state-of-the-art open cycles, with slightly improved specific fuel consumption performance. Optimum semi-closed cycles furthermore operate at higher overall pressure ratios than open cycles and make use of recuperators with higher effectiveness as the mass penalty of the recuperator is smaller due to the lower engine mass flow rates.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multi-objective optimisation of semi-closed cycle engines for high-altitude UAV propulsion

2019

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“…Another interesting heat exchanged engine concept, but based on an even more complex mechanical arrangement, is the semi‐closed cycle (Rodgers, 1999; Meitner and Senick, 2000). The turboprop concept shown on Figure 12 shows intercooling and recuperation.…”

Section: Small Heat Exchanged Engine Conceptsmentioning

confidence: 99%

Recuperated gas turbine aeroengines. Part III: engine concepts for reduced emissions, lower fuel consumption, and noise abatement

McDonald

Massardo

Rodgers³

et al. 2008

Aircraft Engineering and Aerospace Technology

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PurposeThis paper seeks to evaluate the potential of heat exchanged aeroengines for future Unmanned Aerial Vehicle (UAV), helicopter, and aircraft propulsion, with emphasis placed on reduced emissions, lower fuel burn, and less noise.Design/methodology/approachAeroengine performance analyses were carried out covering a wide range of parameters for more complex thermodynamic cycles. This led to the identification of major component features and the establishing of preconceptual aeroengine layout concepts for various types of recuperated and ICR variants.FindingsNovel aeroengine architectures were identified for heat exchanged turboshaft, turboprop, and turbofan variants covering a wide range of applications. While conceptual in nature, the results of the analyses and design studies generally concluded that heat exchanged engines represent a viable solution to meet demanding defence and commercial aeropropulsion needs in the 2015‐2020 timeframe, but they would require extensive development.Research limitations/implicationsAs highlighted in Parts I and II, early development work was focused on the use of recuperation, but this is only practical with compressor pressure ratios up to about 10. For today's aeroengines with pressure ratios up to about 50, improvement in SFC can only be realised by incorporating intercooling and recuperation. The new aeroengine concepts presented are clearly in an embryonic stage, but these should enable gas turbine and heat exchanger specialists to advance the technology by conducting more in‐depth analytical and design studies to establish higher efficiency and “greener” gas turbine aviation propulsion systems.Originality/valueIt is recognised that meeting future environmental and economic requirements will have a profound effect on aeroengine design and operation, and near‐term efforts will be focused on improving conventional simple‐cycle engines. This paper has addressed the longer‐term potential of heat exchanged aeroengines and has discussed novel design concepts. A deployment strategy, aimed at gaining confidence with emphasis placed on assuring engine reliability, has been suggested, with the initial development and flight worthiness test of a small recuperated turboprop engine for UAVs, followed by a larger recuperated turboshaft engine for a military helicopter, and then advancement to a larger and far more complex ICR turbofan engine.

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Flame Blowout Stability in Vitiated Combustion

Singh¹,

Lear²

2009

7th International Energy Conversion Engineering Conference

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Demonstration of a Semi-Closed Cycle, Turboshaft Gas Turbine Engine

Cited by 5 publications

References 2 publications

Multi-objective optimisation of semi-closed cycle engines for high-altitude UAV propulsion

Multi-objective optimisation of semi-closed cycle engines for high-altitude UAV propulsion

Recuperated gas turbine aeroengines. Part III: engine concepts for reduced emissions, lower fuel consumption, and noise abatement

Flame Blowout Stability in Vitiated Combustion

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