Sökning: "aircraft engines"

Visar resultat 1 - 5 av 43 avhandlingar innehållade orden aircraft engines.

  1. 1. Towards Environmentally Friendly Aero Engines

    Författare :Rickard Avellan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; geared turbofan; energy efficiency; turbofan; environmentally friendly; DDTF; aero engines; GTF; aircraft;

    Sammanfattning : Since the introduction of subsonic jet driven commercial aircraft, incremental improvements in overall efficiency has been a driving requirement as well as a selling argument for the engine industry. The historical overall efficiency improvement is the result of continuous advances in aerodynamic design, increase of overall pressure ratios, turbine inlet temperatures and propulsive efficiencies in parallel with the development of stronger and lighter materials. LÄS MER

  3. 2. On the Analysis of Energy Efficient Aircraft Engines

    Författare :Oskar Thulin; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Performance modelling; Aero engine; Turbofan; Aircraft engine; Installed propulsion; Ultra high bypass ratio; Exergy analysis; Engine weight estimate; Variable area fan nozzle; Multiple pivoting flaps; Translating cowls;

    Sammanfattning : Aero engine performance analysis is highly multidimensional using various measures of component performance such as turbomachinery and mechanical efficiencies, and pressure loss coefficients. Using conventional performance analysis, relying on only the laws of thermodynamics, it is possible to understand how the performance parameters affect the component performance, but it is difficult to directly compare the magnitude of various loss sources. LÄS MER

  4. 3. Quasi-analytical Modelling and Optimisation Techniques for Transport Aircraft Design

    Författare :Askin T. Isikveren; KTH; []
    Nyckelord :aircraft; conceptual; design; specifications; atmosphere; geometry; weight; aerodyanmics; propulsion; operational performance; stability and control; constrained multi-objective optimisation; computer aided design; regional; business; high-transonic; ;

    Sammanfattning : The research work presented here focuses on the subject oftransport aircraft design at the pre-design or conceptuallevel. The primary topics addressed are: (1) generation of avast array of new quasi-analytical expressions to permit aconceptual treatment of commercial and business transportaircraft with adequate sensitivity for more advanced tradestudies; (2) review and adoption of a method to predictstability and control characteristics (using the Mitchellmethod); (3) a study of the relative merits between variousmethods in facilitating an expedient and robust constrainedmulti-objective optimisation result within the context oftraditional conceptual design problems (Genetic Algorithms andNelder-Mead Simplex search); (4) creation of a software packageas a new and unique conceptual tool that permits the generationof design proposals in an accurate yet expeditious manner; and,(5) practical demonstration of the new conceptual designsoftware package by undertaking some actual aircraft designproposals. LÄS MER

  5. 4. Improved remaining useful life estimations for on-condition parts in aircraft engines

    Författare :Veronica Fornlöf; Anna Syberfeldt; Anders Skoogh; Högskolan i Skövde; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Aircraft engine maintenance; Reliability; Remaining useful life; On-condition parts; Prognosis; Technology; Teknik; Production and Automation Engineering; Produktion och automatiseringsteknik;

    Sammanfattning : This thesis focuses on obtaining better estimates of remaining life for on-condition (OC) parts in aircraft engines. Aircraft engine components are commonly classified into three categories, life-limited parts (LLP), OC-parts and consumables. Engine maintenance typi-cally accounts for 10% to 20% of aircraft-related operating cost. LÄS MER

  7. 5. Aviation and the Environment- Evaluation of High Propulsive Efficiency Engines

    Författare :Linda Larsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aircraft engine; Environment; Open rotor; Turbofan; Aviation;

    Sammanfattning : There has been more than a tenfold increase in passenger kilometers traveled over the last 40 years. The highest rate of growth today is in developing countries such as China and India. These countries also have the two largest populations in the world. LÄS MER