GB971222A - Gas turbine power plant - Google Patents

Abstract

971,222. Gas turbine jet engines; ram jet engines. ROLLS-ROYCE Ltd. Dec. 17, 1962, No. 47628/62. Heading F1J. A gas turbine jet engine comprises an air intake passage, compressor means, main combustion equipment, turbine means, reheat combustion equipment and an exhaust passage. A supplementary air duct communicates with the air intake passage and is adapted to receive ram air therefrom, the supplementary air duct by-passing the compressor means, primary combustion equipment, turbine means and reheat combustion equipment and communicating with the exhaust passage. A ram air duct communicates by way of valve means with the supplementary air duct, the valve means being settable in either open or closed positions whereby ram air flowing through the supplementary air duct is either directed into or prevented from entering the ram air duct, the ram air duct communicating with the main flow duct upstream of the reheat combustion equipment so as to be adapted to deliver ram air thereto, so that when the valve means is set in the open position and the primary combustion equipment is shut down, the power plant may be operated as a ram-jet engine. When the valve means is set in the closed position, the power plant may be operated as a gas turbine engine, the ram air passing through the supplementary air duct into the exhaust passage serving to control the expansion of the exhaust gases in the exhaust passage. The engine shown in Fig. 1 comprises a low pressure compressor 16 and a low pressure turbine 21 mounted on a common shaft 25, a high pressure compressor 18 and a high pressure turbine 20 mounted on a common shaft 26, main combustion equipment 19, reheat combustion equipment 22 and an exhaust passage 23 which terminates in a propulsion nozzle 24. The compressors 16 and 18 have inlet guide vanes 15 and 17 respectively, the vanes being adjustable by means of a ram 30 between either open or closed positions. The engine comprises also a supplementary air duct 13 through which ram air from the intake 12 may pass to the turbine exhaust passage 23, pivotable flap valves 31 being provided at the outlet of the duct 13 into the exhaust passage. A ram air duct 32 is also provided, communicating at its upstream end with the supplementary air duct 13 by way of openings controlled by flap valves 33, and at its downstream end with the exhaust passage 23 upstream of the reheat equipment 22 by way of openings controlled by flap valves 35. At speeds above Mach 2À6, the inlet guide vanes 15 and 17 are closed, the flap valves 33 and 35 are open and the flap valves 31 closed, the reheat combustion equipment being brought into operation so that the engine functions as a ram-jet engine. In a second embodiment, Fig. 2, the gas turbine engine is of the by-pass type, the by-pass passage 32a serving as the ram air duct. The by-pass passage discharges into the turbine exhaust passage 23a upstream of the reheat equipment 22a by way of shoots 37. Specification 971,221 is referred to.