Контрольная работа № 6(i)

I. Прочитайте весь текст, а затем письменно переведите на русский язык 1-2 абзацы. Английский текст перепишите на левой странице тетради, русский - на правой:

THE RAMJET ENGINE

1. The simplest type of air-breathing engine is the ramjet engine. The engine consists of a diffuser, a combustion chamber, and a discharge nozzle. The function of a diffuser is to convert the kinetic energy of the entering air into a pressure rise by decreasing the air velocity. The diffuser delivers the air at a static pressure higher than the atmospheric pressure to the combustion chamber, where fuel is mixed with the air and ignited.

2. The burning causes the specific volume of the air to increase; thus, the air is accelerated in the combustion chamber, where it burns at approximately constant pressure to a high tempera­ture. High temperature and high pressure gases are delivered to the exhaust nozzle to produce an exit velocity greater than the entrance velocity. The fuel utilized in this type of engine is usually a liquid hydrocarbon; however, solid fluids can be used to produce a propulsive thrust.

3. Theoretically, ramjet operation is limited to altitudes below 90.000 feet because atmospheric oxygen is necessary for combustion. Тhe velocity that can be attained by a ramjet en­gine is unlimited, theoretically. Actually, the faster it travels the better it operates and the more thrust it develops. Its speed is limited, however, at approximately Mach 5.0 because the skin temperature as a result of frictional heating has a harmful effect on the metals used in construction. The major disadvantages of a ramjet power plant is that the higher the operational speed for which it is designed, the higher the speed to which it must be boosted before initial starting of the engine.

II. Найдите в тексте ответы на следующие вопросы:

1. What parts does the ramjet engine consists of?

2. What is the major disadvantage of a ramjet power plant?

Date: 2016-05-25; view: 440; Нарушение авторских прав