Развитие профессиональных компетенций студентов технических вузов (английский язык) (190,00 руб.)

УДК 42 ББК СГАУ: Ш143.21.923 ISBN 978-5-7883-0809-8 2 © Самарский государственный аэрокосмический университет, 2010 Unit I COMPRESSORS Before you Begin I. Have you ever met the term “Compressor” in technical literature? <...> Brainstorm all possible terms related to the topic. compressors Reading I. In the text, find definitions of : a) -compressor efficiency -axial flow compressor -centrifugal flow compressor -centrifugal-axial-flow compressor -stage -rotor blades -stator vanes 3 b) try to define the meaning of the term “compression ratio” as you understand it. <...> Compressors The role of the compressor in a gas turbine engine is to provide a maximum of high-pressure air which can be heated in the limited volume of the combustion chamber and then expanded through the turbine. <...> The energy that can be released in the combustion chamber is proportional to the mass of air consumed; therefore the compressor is one of the most important components of the gas turbine engine since its efficient operation (maximum compression with minimum temperature rise) is the key to high overall engine performance. <...> The compressor efficiency will determine the power necessary to create the pressure rise of a given airflow and will affect the temperature change which can take place in the combustion chamber. <...> Types of Compressors All gas turbine engines use one of the following forms of compressors: 4 1. <...> The Axial-Flow Compressors The axial-flow compressor is made up of a series of rotating airfoils called rotor blades and a stationary set of airfoils called stator vanes. <...> As its name implies, the air is being compressed in a direction parallel to the axis of the engine. <...> The entire compressor is made up of a series of alternating rotor and stator vane stages. <...> Some axial-flow designs have two or more compressors or spools which are driven by separate turbines and are therefore free to rotate at different speeds. <...> Furthermore, the number of compressor blades and stator vanes (which can exceed 1000 in a large jet engine), the close fits required for efficient air pumping, and the much narrower range of possible operating conditions, make this type of compressor very complex and very expensive to manufacture. <...> Modern manufacturing techniques are bringing <...>