Magyarország (topográfiai térkép) (1870)

Mezőkövesd környékeTeljes méret lemezhatárig: 34,5x48 cmUtakkal, vasutakkalMilitärgeographisches Institut domborpecsétjével ellátvaMűvelési ágak bejelölveDomborzat csíkozással ábrázolvaTelepülések nagyság szerint jellel, névvel jelölveA. Lang scrips., G. Pellischek sc

Thermodynamic Characteristics of a Turboprop Engine with Heat Exchangers for Unmanned Aerial Vehicles

UAVs are becoming of always greater importance, both in military and civil applications. One of the main reasons of their growth is the realization of very efficient and reliable guiding systems, that allow a thorough remote vehicle control. An important UAV aspect is the endurance capability. A flight length of 24 hours or more is often required for their missions. This makes the engine fuel consumption a fundamental aspect. For a power range comprised between 300 - 900 kW, the turboprop engine is commonly used. To reduce the engine fuel consumption, and consequently increase the UAV endurance characteristics, a turboprop with intercooling and regeneration has been studied. Regeneration is a techniques that allows to recover the exhaust gas heat at the power turbine outlet, to pre-heat air at the combustion chamber inlet. This allows to reduce the specific fuel consumption. The intercooled compression process allows to reduce the compressor absorbed power and consequently rise the output power. A thermodynamic numeric program that simulates the behavior of a turboprop with regeneration at different engine and operating conditions has been developed. The program allows to compute the thermodynamic working cycle and hence the main engine performances, as specific power, thermal efficiency and specific fuel consumption. An offdesign analysis is then performed to evaluate the engine behavior when operating at different conditions respect to the design point. © 2013 by Roberto Andriani

Assessment of Future Aero-engine Designs with Intercooled and Intercooled Recuperated Cores

Reduction in CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction in engine nacelle drag and weight. Conventional turbofan designs, however, that reduce CO2 emissions—such as increased overall pressure ratio designs—can increase the production of NOx emissions. In the present work, funded by the European Framework 6 collaborative project NEW Aero engine Core concepts (NEWAC), an aero-engine multidisciplinary design tool, Techno-economic, Environmental, and Risk Assessment for 2020 (TERA2020), has been utilized to study the potential benefits from introducing heat-exchanged cores in future turbofan engine designs. The tool comprises of various modules covering a wide range of disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, as well as production, maintenance and direct operating costs. Fundamental performance differences between heat-exchanged cores and a conventional core are discussed and quantified. Cycle limitations imposed by mechanical considerations, operational limitations and emissions legislation are also discussed. The research work presented in this paper concludes with a full assessment at aircraft system level that reveals the significant potential performance benefits for the intercooled and intercooled recuperated cycles. An intercooled core can be designed for a significantly higher overall pressure ratio and with reduced cooling air requirements, providing a higher thermal efficiency than could otherwise be practically achieved with a conventional core. Variable geometry can be implemented to optimize the use of the intercooler for a given flight mission. An intercooled recuperated core can provide high thermal efficiency at low overall pressure ratio values and also benefit significantly from the introduction of a variable geometry low pressure turbine. The necessity of introducing novel lean-burn combustion technology to reduce NOx emissions at cruise as well as for the landing and take-off cycle, is demonstrated for both heat-exchanged cores and conventional designs. Significant benefits in terms of NOx reduction are predicted from the introduction of a variable geometry low pressure turbine in an intercooled core with lean-burn combustion technology