40 research outputs found

    How Combustion made us Human

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    Flight Performance and Propulsio

    Energy transition in aviation: The role of cryogenic fuels

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    Aviation is the backbone of our modern society. At present, around 4.5 Billion passengers travel through the air every year and aviation is responsible for around 5 % of anthropogenic causes of Global Warming (Lee et al, 2009). With the increase in global GDP, the number of travellers is expected to increase to 7.5 Billion by 2037 and to around 15 Billion by 2050. Even though the crude oil prices are low at the moment, with finite petroleum reserves available on our planet, it is expected that the Jet fuel prices will increase in the future. Moreover using kerosene causes several emissions which are bad for the environment. Liquefied Natural gas (LNG) and Liquid Hydrogen (LH2) can provide an attractive alternative for aviation.Aircraft Noise and Climate EffectsFlight Performance and Propulsio

    A review of gas turbine engine with inter-stage turbine burner

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    Society is going through transformations at a rate that is unprecedented in human history. One such transformation is the energy transition, which will affect almost every facet of our society. Gas turbine engines are state of the art machines, a backbone of modern society, and used in various applications, right from power generation to propelling aircraft and ships. This paper reviews the possibilities offered by the Inter-stage Turbine Burner (ITB) configuration for both aviation and power generation with a view on sustainability and fuel flexibility. First, the thermodynamic characteristics of a Brayton-Joule cycle with ITB is elaborated, followed by discussions on the design and the off-design performance characteristics of such a gas turbine architectural variation. Finally, the viability of ITB architecture in reducing emissions and enabling “Energy Mix” in aviation is elaborated. The paper concludes with an outlook on the technological readiness ladder that the engineering community will have to address in the future.Aircraft Noise and Climate EffectsFlight Performance and Propulsio

    Performance assessment of a Multi-fuel Hybrid Engine for Future Aircraft

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    This paper presents performance assessment of the proposed hybrid engine concept using Liquid Natural Gas (LNG) and kerosene. The multi-fuel hybrid engine is a new engine concept integrated with contra rotating fans, sequential dual combustion chambers to facilitate “Energy Mix” in aviation and a Cryogenic Bleed Air Cooling System (CBACS). The current analysis focuses on three aspects: 1) effects of the CBACS on the HPT cooling air requirement and the associated effects on the cycle efficiency; 2) performance optimization of the hybrid engine; 3) assessment of the emission reduction by the hybrid engine. An integrated model framework consisting of an engine performance model, a turbine cooling model, and a Cryogenic Heat Exchanger (CHEX) model is used to perform the analyses. The parametric analysis shows that using the CHEX, the bleed air temperature can be reduced significantly (up to 600 K), which reduces the turbine cooling air requirement by more than 50%, while increasing the LNG temperature by 300K. Consequently, the cycle efficiency improves even further. Depending on the fuel flow distribution between two combustors. The CO2 emission from the hybrid engine is lower by 15% to 30%. The mission analysis along with the Multi-Fuel Blended Wing Body aircraft shows a reduction in NOx emissions by 80% and CO2 emission by 50% when compared to B-777 200ER.Aircraft Noise and Climate EffectsFlight Performance and Propulsio

    Thermodynamic analysis of a zero-emission combustion cycle for energy transition

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    The power sector accounts for ∌40% of global energy-related CO2 emissions. Its decarbonization by switching to low-carbon renewables is essential for a sustainable future. Existing electrical grids, however, have limited capacity to absorb the variability introduced by these new energy sources and rely largely on natural-gas-based power generation. For deep decarbonization, alternative solutions to increase grid flexibility are needed. Among these, energy storage is expected to have a key role. This paper proposes a unique energy storage and re-conversion system by coupling the hydrogen combustion in supercritical CO2 (HYCOS) cycle, a zero-emission combustion cycle, with long-term/seasonal energy storage based on green H2 production. This power cycle is expected to be highly scalable and compact and can deliver power at net electrical efficiency between 55% and 60% at distributed generation levels. Thus, it can be highly competitive with existing solutions such as fuel cells, reciprocating engines, and gas turbines.Flight Performance and Propulsio

    Discussion: “Beyond Brayton Cycle: It is Time to Change the Paradigm” (S. Can G€ulen, 2018, ASME J. Eng. Gas Turbine Power, 140(11), p. 111702)

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    Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Flight Performance and Propulsio

    Performance analysis of an Aero Engine with Interstage Turbine Burner

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    The historical trends of reduction in fuel consumption and emissions from aero engines have been mainly due to the improvement in the thermal efficiency, propulsive efficiency and combustion technology. The engine Overall Pressure Ratio (OPR) and Turbine Inlet Temperature (TIT) are being increased in the pursuit of increasing the engine thermal efficiency. However, this has an adverse effect on engine NOx emission. The current paper investigates a possible solution to overcome this problem for future generation Very High Bypass Ratio (VHBR)/Ultra High Bypass Ratio (UHBR) aero-engines in the form of an Inter-stage Turbine Burner (ITB). The ITB concept is investigated on a next generation baseline VHBR aero engine to evaluate its effect on the engine performance and emission characteristics for different ITB energy fractions. It is found that the ITB can reduce the bleed air required for cooling the HPT substantially (around 80%) and also reduce the NOx emission significantly (>30%) without penalising the engine specific fuel consumption.Aircraft Noise and Climate EffectsFlight Performance and Propulsio

    Effect of dilution in an inter-turbine Flameless combustor

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    Alternatives to combustion in aircraft engines are not expected to become feasible in the decades to come. As the aviation traffic increases and regulations become more stringent, reduction in pollutant emissions are needed. The Flameless Combustion (FC) regime has been one of the promising candidates to achieve lower emissions in gas turbine engines. This combustion regime is characterized by welldistributed reactions, with low peak temperatures, resulting in lower emissions and acoustic oscillations. However, the attainment of the FC regime is not straight forward considering the conditions and requirements of gas turbines. Most of the previous combustor design attempts failed to provide broad operational range, high combustion efficiency, or were difficult to integrate in an engine. Along with a novel aircraft concept, the European project AHEAD (Advanced Hybrid Engines for Aircraft Development) resulted in the conceptual design of a gas turbine engine with two sequential combustion chambers1. As the aircraft concept allows the use of cryogenic fuels, the first combustion chamber was designed to operate with hydrogen or natural gas. The second is the inter-turbine combustor herein studied, which would operate under the FC regime burning conventional fuels. Flight Performance and Propulsio

    A CFD Based Parametric Analysis of S-shaped Inlet for a Novel Blended Wing Body Aircraft

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    The Advisory Council for Aeronautics Research in Europe (ACARE) has set an ambitious array of objectives to be accomplished by 2050 for civil aviation. It is often claimed that complying with those targets will not require evolution but, rather, revolution. If the growth in aviation has to be sustained in the future, then we must come up with radical aircraft and engine configurations which can meet the demands of future aviation. The AHEAD project (co-funded by the European Commission) investigated a novel multi-fuel blended wing body aircraft with a unique propulsion system to address the challenges of the future. The engine for this aircraft uses an embedded hybrid engine exploiting the boundary layer ingestion technique to increase the propulsive efficiency. Two major consequences of BLI are vital in this regard. Namely, loss of total pressure recovery and increased total pressure distortion at the Aerodynamic Interface Plane (AIP) or the engine fan-face. Hence, the inlet performance is measured by the total Pressure Recovery Factor (PRF) and Distortion Coefficient (DC60). The current research work aims to design an embedded inlet on a Blended Wing Body (BWB) aircraft that produces maximum value of PRF and minimum DC60. The aim of this research is to investigate the S-shaped inlet to understand the effect of various geometrical parameters on its performance. The Knowledge Based Engineering platform ParaPy is used to parametrize the S-shaped inlet and generate a variety of inlet geometries and volume meshes. These different variants were analysed using the AnsysÂź CFD code.Flight Performance and PropulsionControl & Simulatio

    A Novel Engine Architecture for Low NOx Emissions

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    The fuel efficiency of turbofan engines has improved significantly, hence reducing aviation's CO2 emissions. However, the increased operating pressure and temperature for fuel efficiency cause adverse effects on NOx emissions. Therefore, a novel engine concept, which can reduce NOx emissions without affecting the cycle efficiency, is of high interest to the aviation community. This paper investigates the potential of an intercooler and inter-turbine burner (ITB) for the future low NOx aircraft propulsion system. The study evaluates performance and NOx emissions of four engine architectures: a very high bypass ratio (VHBR) turbofan engine (baseline), a VHBR engine with intercooler, a VHBR engine with ITB, and a VHBR engine with both intercooler and ITB. The cycles are optimized for minimum cruise Thrust Specific Fuel Consumption (TSFC), considering the same design space, thrust requirements, and operational constraints. The ITB is only used during take-off to minimize cruise fuel consumption. The analysis shows that using an ITB solely, with the energy split of 75% (the first burner) / 25% (ITB), reduces the cruise NOx emission by 26%, and the cruise TSFC slightly by 0.5%. The intercooler alone reduces the NOx emissions by 16% and the cruise TSFC by 0.8%. The combination of intercooler and ITB reduces the NOx emissions further by 38%. The analysis confirms that introducing an intercooler and ITB can potentially resolve the contradicting effects of fuel efficiency and NOx emissions for the future advanced turbofan engine. Aircraft Noise and Climate EffectsFlight Performance and Propulsio
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