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Turbofan

About: Turbofan is a research topic. Over the lifetime, 4114 publications have been published within this topic receiving 39490 citations. The topic is also known as: fanjet & turbofan engine.


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Journal ArticleDOI
TL;DR: In this paper, a computational viewpoint on the problems of design and numerical simulation for the nozzles of modern aircraft turbofan engines is presented, including simulation of near and far field of a nozzle, for generation of input perturbations and for processing the far-field noise.

17 citations

Patent
22 Jan 2009
TL;DR: The Velarus Propulsion (VPx) as discussed by the authors is an aircraft propulsion system (APS) for turbofan engines that employs a modified combustor to increase the combustion chamber temperature.
Abstract: The invention adds details and alternate design supplementing the concept established with my patent application Ser. No. 12/013,431, Aircraft Propulsion System (APS). The APS ultimate fuel economy objectives requires long term design development, and this invention compromises some fuel economy for the expediency of short term implementation of a heat regeneration for turbofans via the re-arrangement of existing components and a few unique items readily designed. While this Velarus Propulsion (VPx) attains only 42% fuel economy, it retains the original APS fundamental architecture implementing heat regeneration for a turbofan engine, as well as the additional benefits of noise and emission abatement. This invention consists of the three APS technologies as follows: a) A novel arrangement of the power generation core features the turbine exhaust entering directly into the thrust chamber, thus providing heat regeneration with an appropriate configuration of the thrust chamber. b) The design of a modified combustor introduces the concept of a supersonic nozzle driving the turbines which allows for greater combustor's chamber temperature while injecting the gases at temperatures acceptable to current turbine blade metallurgy. This feature increases the engine thermal efficiency. c) The hub design allows for two options, a simpler fixed fanblade design or an advanced controllable pitch fan blade, increasing the mission and performance flexibility of a given turbofan size. In addition, this invention adds functionality to the aft cone, such as debris purge, accessories installation, and thrust reversers free from hot gases.

17 citations

Book ChapterDOI
01 Sep 2006
TL;DR: In this paper, the authors consider the operating conditions experienced by the high-pressure turbine blades in a large civil turbofan engine, such as the Rolls-Royce Trent 800 or General Electric GE90.
Abstract: The gas turbine consists of many different pieces of turbomachinery, but the rows of turbine blading are of the greatest importance since many engine characteristics, for example the fuel economy and thrust, depend very strongly on the operating conditions which can be withstood by them. Thus very arduous temperatures and stresses are experienced by the materials employed, which are pushed near to the limits of their capability. This is particularly the case for the high-pressure blades, which are located nearest to the hot gases emerging from the combustion chamber. Their function is to extract work from the gas stream and to convert it to mechanical energy in the form of a rotating shaft, which drives the high-pressure compressor. A consideration of the operating conditions experienced by the high-pressure turbine blades in a large civil turbofan engine, such as the Rolls-Royce Trent 800 or General Electric GE90, confirms this point. The temperature of the gas stream is about 1750 K, which is above the melting temperature of the superalloys from which the blades are made. The high-pressure shaft develops a power of about 50 MW – hence, with about 100 blades, each extracts about 500 kW, which is sufficient to satisfy the electricity requirement of about 500 homes. Each row of blades is expected to last at least 3 years, assuming they operate at 9 h/day. This is equivalent to about 5 million miles of flight, or ~500 circumferences of the world.

17 citations

Proceedings ArticleDOI
18 Sep 2014
TL;DR: In this article, the authors describe the research carried out in the European Commission co-funded project LEMCOTEC (Low Emission Core Engine Technology), which is aiming at a significant increase of the engine overall pressure ratio.
Abstract: This paper describes the research carried out in the European Commission co-funded project LEMCOTEC (Low Emission Core Engine Technology), which is aiming at a significant increase of the engine overall pressure ratio. The technical work is split in four technical sub-projects on ultra-high pressure ratio compressors, lean combustion and fuel injection, structures and thermal management and engine performance assessment. The technology will be developed at subsystem and component level and validated in test rigs up to TRL5. The developed technologies will be assessed using three generic study engines (i.e. regional turbofan, mid-size open rotor, and large turbofan) representing about 90% of the expected future commercial aero-engine market. Two additional study engines from the previous NEWAC project will be used for comparison. These are based on intercooled and intercooled-recuperated future engine concepts.The compressor work is targeting efficiency, stability margin and flow capacity by improved aerodynamic design. High-pressure and intermediate-pressure compressors are addressed. The mechanical and thermo-mechanical functions, including the variable-stator-systems, will be improved. Axial-centrifugal compressors with impeller and centrifugal diffuser are under investigation too.Three lean burn fuel injection systems are developed to match the technology to the corresponding engine pressure levels. These are the PERM (Partially Evaporating Rapid Mixing), the MSFI (Multiple Staged Fuel Injection) and the advanced LDI (Lean Direct Injection) combustion systems. The air flow and combustion systems are investigated. The fuel control systems are adapted to the requirements of the ultra-high pressure engines with lean fuel injection. Combustor-turbine interaction will be investigated. A fuel system analysis will be performed using CFD methods.Improved structural design and thermal management is required to reduce the losses and to reduce component weight. The application of new materials and manufacturing processes, including welding and casting aspects, will be investigated. The aim is to reduce the cooling air requirements and improve turbine aerodynamics to support the high-pressure engine cycles.The final objective is to have innovative ultra-high pressure-ratio core-engine technologies successfully validated at subsystem and component level. Increasing the thermal efficiency of the engine cycles relative to year 2000 in-service engines with OPR of up to 70 (at max. condition) is an enabler and key lever of the core-engine technologies to achieve and even exceed the ACARE 2020 targets on CO2, NOx and other pollutant emissions:• 20 to 30 % CO2 reduction at the engine level, exceeding both, the ACARE 15 to 20% CO2 reduction target for the engine and subsequently the overall 50% committed CO2 and the fuel burn reduction target on system level (including the contributions from operations and airframe improvements),• 65 to 70 % NOx reduction at the engine level (CAEP/2) to attain and exceed the ACARE objective of 80% overall NOx reduction (including the contributions from both, operational efficiency and airframe improvement), reduction of other emissions (CO, UHC and smoke/particulates) and• Reduction of the propulsion system weight (engine including nacelle without pylon).Copyright © 2014 by ASME

17 citations

01 Jun 1995
TL;DR: In this paper, the authors quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels and conclude that the dominant source of fan noise is the interaction of incident inlet boundary layer turbulence with the fan rotor.
Abstract: A study has been completed to quantify the contribution of fan broadband noise to advanced high bypass turbofan engine system noise levels The result suggests that reducing fan broadband noise can produce 3 to 4 EPNdB in engine system noise reduction, once the fan tones are eliminated Further, in conjunction with the elimination of fan tones and an increase in bypass ratio, a potential reduction of 7 to 10 EPNdB in system noise can be achieved In addition, an initial assessment of engine broadband noise source mechanisms has been made, concluding that the dominant source of fan broadband noise is the interaction of incident inlet boundary layer turbulence with the fan rotor This source has two contributors, ie, unsteady life dipole response and steady loading quadrupole response The quadrupole contribution was found to be the most important component, suggesting that broadband noise reduction can be achieved by the reduction of steady loading field-turbulence field quadrupole interaction Finally, for a controlled experimental quantification and verification, the study recommends that further broadband noise tests be done on a simulated engine rig, such as the GE Aircraft Engine Universal Propulsion Simulator, rather than testing on an engine statically in an outdoor arena The rig should be capable of generating forward and aft propagating fan noise, and it needs to be tested in a large freejet or a wind tunnel

17 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023163
2022320
2021112
2020131
2019175
2018189