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Gas turbinesA gas turbine is a rotary machine similar in principle to a steam turbine and it consists of three main components: a compressor, a combustion chamber, and a turbine. The air after being compressed in the compressor is heated by burning fuel in it. About ⅔ of the heated air combined with the products of combustion is expanded in a turbine resulting in work output which is used to drive the compressor. The rest (about ⅓) is available as useful work output. Four-stroke cycle (or Otto cycl e) As their name implies, operation of four stroke internal combustion engines have four basic steps that repeat with every two revolutions of the engine: Intake Combustible mixtures are emplaced in the combustion chamber Compression The mixtures are placed under pressure Combustion (Power) The mixture is burnt, almost invariably a deflagration, although a few systems involve detonation. The hot mixture is expanded, pressing on and moving parts of the engine and performing useful work. Exhaust The cooled combustion products are exhausted into the atmosphere Many engines overlap these steps in time; jet engines do all steps simultaneously at different parts of the engines. Дата добавления: 2015-09-27 | Просмотры: 276 | Нарушение авторских прав |