| 1. |
- Gkoutzamanis, Vasilis, et al.
(författare)
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Thermal energy storage for gas turbine power augmentation
- 2019
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Ingår i: Journal of the Global Power and Propulsion Society. - : Global Power and Propulsion Society. - 2515-3080. ; 3, s. 592-608
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Tidskriftsartikel (refereegranskat)abstract
- This work is concerned with the investigation of thermal energy storage (TES) in relation to gas turbine inlet air cooling. The utilization of such techniques in simple gas turbine or combined cycle plants leads to improvement of flexibility and overall performance. Its scope is to review the various methods used to provide gas turbine power augmentation through inlet cooling and focus on the rising opportunities when these are combined with thermal energy storage. The results show that there is great potential in such systems due to their capability to provide intake conditioning of the gas turbine, decoupled from the ambient conditions. Moreover, latent heat TES have the strongest potential (compared to sensible heat TES) towards integrated inlet conditioning systems, making them a comparable solution to the more conventional cooling methods and uniquely suitable for energy production applications where stabilization of GT air inlet temperature is a requisite. Considering the system’s thermos-physical, environmental and economic characteristics, employing TES leads to more than 10% power augmentation.
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| 2. |
- Roy, Arijit Sinha, et al.
(författare)
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Flow instability effects related to purge through a gas turbine chute seal
- 2021
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Ingår i: Journal of the Global Power and Propulsion Society. - : Global Power and Propulsion Society. - 2515-3080. ; 5, s. 111-125
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates flow instabilities inside the cavity formed between the stator and rotor disks of a high-speed turbine rig. The cavity rim seal is of chute seal design. The influence of flow coefficient on the sealing effectiveness at constant purge flow rate through the wheel-space is determined. The effectiveness at different radial positions over a range of purge flow conditions and flow coefficients is also studied. Unsteady pressure measurements have identified the frequency of instabilities that form within the rim seal, phenomena which have been observed in other studies. Frequencies of these disturbances, and their correlation in the circumferential direction have determined the strength and speed of rotation of the instabilities within the cavity. Large scale unsteady rotational structures have been identified, which show similarity to previous studies. These disturbances have been found to be weakly dependent on the purge flow and flow coefficients, although an increased purge reduced both the intensity and speed of rotation of the instabilities. Additionally, certain uncorrelated disturbances have been found to be inconsistent (discontinuous) with pitchwise variation.
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| 3. |
- Vouros, Stavros, et al.
(författare)
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Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans
- 2021
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Ingår i: Journal of the Global Power and Propulsion Society. - : Global Power and Propulsion Society. - 2515-3080. ; 5, s. 164-176
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid-electric propulsion has emerged as a promising technology to mitigate the adverse environmental impact of civil aviation. Boosting conventional gas turbines with electric power improves mission performance and operability. In this work the impact of electrification on pollutant emissions and direct operating cost of geared turbofan configurations is evaluated for an 150-passenger aircraft. A baseline two-and-a-half-shaft geared turbofan, representative of year 2035 entry-into-service technology, is employed. Parallel hybridization is implemented through coupling a battery-powered electric motor to the engine low-speed shaft. A multidisciplinary design space exploration framework is employed comprising modelling methods for multi-point engine design, aircraft sizing, performance and pollutant emissions, mission and economic analysis. A probabilistic approach is developed considering uncertainties in the evaluation of direct operating cost. Sensitivities to electrical power system technology levels, as well as fuel price and emissions taxation are quantified at different time-frames. The benefits of lean direct injection are explored along short-, medium-, and long-range missions, demonstrating 32% NOx savings compared to traditional rich-burn, quick-mix, lean-burn technologies in short-range operations. The impact of electrification on the enhancement of lean direct injection benefits is investigated. For hybrid-electric powerplants, the take-off-to-cruise turbine entry temperature ratio is 2.5% lower than the baseline, extending the corresponding NOx reductions to the level of 46% in short-range missions. This work sheds light on the environmental and economic potential and limitations of a hybrid-electric propulsion concept towards a greener and sustainable civil aviation.
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| 4. |
- Zaccaria, Valentina, 1989-, et al.
(författare)
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Advanced gas turbine hybrid power systems to improve SOFC economic viability
- 2017
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Ingår i: Journal of the Global Power and Propulsion Society. - 2515-3080. ; 1, s. 28-40
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Tidskriftsartikel (refereegranskat)abstract
- Coupling a solid oxide fuel cell (SOFC) with a gas turbineprovides a substantial increment in system efficiency comparedto the separate technologies, which can potentiallyintroduce economic benefits and favor an early market penetrationof fuel cells. Currently, the economic viability of suchsystems is limited by fuel cell short lifetime due to a progressiveperformance degradation that leads to cell failure.Mitigating these phenomena would have a significant impacton system economic feasibility. In this study, the lifetime of astandalone, atmospheric SOFC system was compared to apressurized SOFC gas turbine hybrid and an economic analysiswas performed. In both cases, the power production wasrequired to be constant over time, with significantly differentresults for the two systems in terms of fuel cell operating life,system efficiency, and economic return. In the hybrid system,an extended fuel cell lifetime is achieved while maintaininghigh system efficiency and improving economic performance.In this work, the optimal power density was determined forthe standalone fuel cell in order to have the best economicperformance. Nevertheless, the hybrid system showed bettereconomic performance, and it was less affected by the stackcost.
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