Sökning: "variable cycle"

Visar resultat 1 - 5 av 117 avhandlingar innehållade orden variable cycle.

1. 1. Analysis and Evaluation of Innovative Aero Engine Core Concepts

   Författare :Lei Xu; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; intercooled recuperated cycle; intercooler; intercooled cycle; multidisciplinary optimization; turbofan; innovative core; variable core cycle; thermal efficiency; aero engine;

   Sammanfattning : Turbofan engines, which power the majority of the modern aircraft today, have achieved such a high maturity that small improvements of the engine performance requires a large investment. More innovative technologies, including those related to the engine cores, become increasinglyattractive due to the high fuel price in recent years as well as the strict regulations on emissions. LÄS MER

3. 2. Development of Methods for Analysis and Optimization of Complex Jet Engine Systems

   Författare :Tomas Grönstedt; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; optimal control; variable cycle engine; performance analysis; double bypass variable cycle engine; jet engine; BDF methods; selective bleed variable cycle engine; turbofan; ODAE;

   Sammanfattning : This thesis describes the development of GESTPAN (GEneral Stationary and Transient Propulsion ANalysis), a generalized system for the design, steady-state and transient simulation of gas turbine systems. Some of the main achievements in the thesis are related to the development of new algorithms or integration of existing numerics tailored to simplify the structure and use of generalized gas turbine simulation systems. LÄS MER

4. 3. Modelling of cavity partial discharges at variable applied frequency

   Författare :Cecilia Forssén; Roland Eriksson; Hans Edin; Peter H.F. Morshuis; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; measurements; modelling; variable frequency; cavities; disc-shaped; polycarbonate; Electric power engineering; Elkraftteknik;

   Sammanfattning : The presence of partial discharges (PD) in high voltage components is generally a sign of defects and degradation in the electrical insulation. To diagnose the condition of high voltage insulation, PD measurements is commonly used. LÄS MER

5. 4. Partial Discharges Studied with Variable Frequency of the Applied Voltage

   Författare :Hans Edin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diagnostic methods; partial discharges; phase resolved; variable frequency; dielectric spectroscopy; dielectric response; harmonics; insulation; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : This thesis concerns partial discharge (PD) diagnostics withvariable frequency of applied voltage in the frequency range 1mHz - 400 Hz. The exploration of a new type of spectroscopythat combines partial discharge analysis and dielectricresponse is demonstrated. LÄS MER

7. 5. On the Design of Energy Efficient Aero Engines: Some Recent Innovations

   Författare :Rickard Avellan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbofan; aero engine; inter-turbine reheat; emissions; variable cycle; energy efficiency; propeller; NOx; MDO;

   Sammanfattning : In the light of the energy crisis of the 1970s, the old aerospace paradigm of flying higher and faster shifted towards the development of more energy efficient air transport solutions. Today, the aeronautical research and development community is more prone to search for innovative solutions, in particular since the improvement rate of change is decelerating somewhat in terms of energy efficiency, which still is far from any physical limits of aero engine and aircraft design. LÄS MER