Spray Combustion Modeling in Lean Direct Injection Combustors, Part I: Single-Element LDI

Dewanji, D.; Rao, Arvind Gangoli

doi:10.1080/00102202.2014.965810

Cited by 16 publications

(5 citation statements)

References 16 publications

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“…Lean direct injection (LDI) is a lean-burn combustion concept, where fuel is directly injected into the combustion chamber and quickly mixed with a large portion of air. Therefore, LDI can achieve reduced peak flame temperatures at medium to high power compared to traditional RQL combustors (Dewanji and Rao, 2015). However, LDI is more sensitive to combustion instabilities due to the challenging uniformity requirements in the fuel-air mixture before the reaction (Liu et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

Vouros

Kavvalos

Sahoo

et al. 2021

J. Glob. Power Propuls. Soc.

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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 multi-disciplinary 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% NO<italic><sub>x</sub></italic> 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 NO<italic><sub>x</sub></italic> 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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Section: Introductionmentioning

confidence: 99%

Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

Vouros

Kavvalos

Sahoo

et al. 2021

J. Glob. Power Propuls. Soc.

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show abstract

“…Apart from hybridization, low-emissions combustor technologies have been proposed to directly mitigate the environmental impact at source. Lean direct injection (LDI) can achieve reduced peak flame temperatures at medium to high power compared to traditional rich-burn quick-quench lean-burn (RQL) combustors (Dewanji et al, 2015). However, LDI is more sensitive to combustion instabilities due to the challenging uniformity requirements in the fuel-air mixture before the reaction (Liu et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Enabling the Potential of Hybrid Electric Propulsion Through Lean-Burn-Combustion Turbofans

Vouros¹,

Kavvalos²,

Sahoo³

et al. 2020

Proceedings of Global Power &Amp; Propulsion Society

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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 a realistic mission scenario, demonstrating 32% NOx savings compared to traditional rich-burn, quick-mix, lean-burn technologies. The impact of electrification on the enhancement of lean direct injection benefits is investigated. For hybrid-electric powerplants, the takeoff to cruise turbine entry temperature ratio is 2.5% lower than the baseline, extending the corresponding NOx reductions to the level of 46%. 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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“…Dewanji and Rao. 14,15 conducted LES simulations of both a single and a nine-element LDI combustor at atmospheric pressure for an inlet air temperature of 776 K and equivalence ratios of 0.41 and 0.7. Formation of vortex structures in the gas phase such as the VBB and the PVC were found to be critical to fuel distribution and consequently the location of the flame front in the combustor.…”

Section: Introductionmentioning

confidence: 99%

Parametric investigation of combustion instabilities in a single-element lean direct injection combustor

Gejji

Huang

Fugger

et al. 2018

International Journal of Spray and Combustion Dynamics

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Self-excited combustion dynamics in a liquid-fueled lean direct injection combustor at high pressure (1 MPa) are described. Studied variables include combustor and air plenum length, inlet air temperature, equivalence ratio, fuel nozzle location, and fuel composition. Measured pressure oscillations were dependent on combustor geometry and ranged from about 1% of mean chamber pressure at low equivalence ratio, up to 20% at high equivalence ratio. In the most unstable cases, strong pressure modes were measured throughout the frequency spectrum including a band around 1.2-1.5 kHz representing the 4th longitudinal mode, and another band around 7 kHz. The oscillation amplitudes have a non-monotonic dependency on air temperature, and are affected by the placement of the fuel nozzle relative to the throat of the subsonic swirling air flow. The parametric survey provides a rich dataset suitable for validating high-fidelity simulations and their subsequent use in analyzing and interpreting the complex combustion dynamics.

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Spray Combustion Modeling in Lean Direct Injection Combustors, Part I: Single-Element LDI

Cited by 16 publications

References 16 publications

Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

Enabling the Potential of Hybrid Electric Propulsion Through Lean-Burn-Combustion Turbofans

Parametric investigation of combustion instabilities in a single-element lean direct injection combustor

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