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- Kyprianidis, Konstantinos G., et al.
(författare)
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EVA : A Tool for EnVironmental Assessment of Novel Propulsion Cycles
- 2008
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Ingår i: <em><em></em></em>ASME Turbo Expo 2008: Power for Land, Sea, and AirVolume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric PowerBerlin, Germany, June 9–13, 2008. - 9780791843123 - 0791838242 ; , s. 547-556
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Konferensbidrag (refereegranskat)abstract
- This paper presents the development of a tool for EnVironmental Assessment (EVA) of novel propulsion cycles implementing the Technoeconomical Environmental and Risk Analysis (TERA) approach. For nearly 3 decades emissions certification and legislation has been mainly focused on the landing and take-off cycle. Exhaust emissions measurements of NOx, CO and unburned hydrocarbons are taken at Sea Level Static (SLS) conditions for 4 different power settings (idle, descent, approach and take-off) and are consecutively used for calculating the total emissions during the ICAO landing and take-off cycle. With the global warming issue becoming ever more important, stringent emissions legislation is soon to follow, focusing on all flight phases of an aircraft. Unfortunately, emissions measurements at altitude are either extremely expensive, as in the case of altitude test facility measurements, or unrealistic, as in the case of direct in flight measurements. Compensating for these difficulties, various existing methods can be used to estimate emissions at altitude from ground measurements. Such methods, however, are of limited help when it comes to assessing novel propulsion cycles or existing engine configurations with no SLS measurements available. The authors are proposing a simple and fast method for the calculation of SLS emissions, mainly implementing ICAO exhaust emissions data, corrections for combustor inlet conditions and technology factors. With the SLS emissions estimated, existing methods may be implemented to calculate emissions at altitude. The tool developed couples emissions predictions and environmental models together with engine and aircraft performance models in order to estimate the total emissions and Global Warming Potential of novel engine designs during all flight phases (i.e. the whole flight cycle). The engine performance module stands in the center of all information exchange. In this study, EVA and the described emissions prediction methodology have been used for the preliminary design analysis of three spool high bypass ratio turbofan engines. The capability of EVA to radically explore the design space available in novel engine configurations, while accounting for fuel burn and global warming potential during the whole flight cycle of an aircraft, is illustrated.
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| 2. |
- Pascovici, Daniele S., et al.
(författare)
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Weibull Distributions Applied to Cost and Risk Analysis for Aero Engines
- 2008
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Ingår i: <em><em>Proc. ASME</em>.</em> 43123; Volume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric Power. GT2008-51060. - 9780791843123 - 0791838242 ; , s. 681-690
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Konferensbidrag (refereegranskat)abstract
- This paper presents the use of Weibull formulation to the life analysis of different parts of the engine in order to estimate the cost of maintenance, the direct operating costs (DOC) and net present cost (NPC) of future type turbofan engines. The Weibull distribution is often used in the field of life data analysis due to its flexibility—it can mimic the behavior of other statistical distributions such as the normal and the exponential. The developed economic model is composed of three modules: a lifing module, an economic module and a risk module. The lifing module estimates the life of the high pressure turbine blades through the analysis of creep and fatigue over a full working cycle of the engine. The value of life calculated by the lifing is then taken as the baseline distribution to calculate the life of other important modules of the engine using the Weibull approach. Then the lower of the values of life of all the distributions is taken as time between overhaul (TBO), and used into the economic module calculations. The economic module uses the TBO together with the cost of labour and the cost of the engine (needed to determine the cost of spare parts) to estimate the cost of maintenance and DOC of the engine. In the present work five Weibull distributions are used for five important sources of interruption of the working life of the engine: Combustor, Life Limited Parts (LLP), High Pressure Compressor (HPC), General breakdowns and High Pressure Turbine (HPT). The risk analysis done in this work shows the impact of the breakdown of different parts of the engine on the NPC and DOC, the importance that each module of the engine has in its life, and how the application of the Weibull theory can help us in the risk assessment of future aero engines. A detailed explanation of the economic model is done in two other works (Pascovici et. al. [6] and Pascovici et. al. [7]), so in this paper only a general overview is done.
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