Patent GB-1389347-A (GB)
Title: Gas turbine power plant
IPC: F02K3/00
Filed: 1972-05-25
Abstract: 1389347 Gas turbine jet engines; axial-flow compressors ROLLS-ROYCE (1971) Ltd 16 May 1973 [25 May 1972] 24662/72 Headings F1C F1G and F1J A gas turbine power plant comprises a compressor having an upstream part and a downstream part there being a valve assembly disposed between the two parts such that in a first position of the valve air passes from the first part to the second part of the compressor, while in the second position of the valve air passes from the first part to atmosphere and ambient air passes into the second part. In the engine shown in Figs. 1 and 2 the LP compressor 12 is formed in two parts 121 and 122 there being a flow duct 19 of square form therebetween. The valve assembly comprises two pivotally mounted flaps 20 which in a first position 20<SP>A</SP> are disposed parallel to the axis and constitute walls of the flow duct so that air passes from the compressor part 121 to the compressor part 122, the engine then constituting a straight through jet engine. In the second position 20<SP>B</SP> the flaps 20 are moved pivotally so as to constitute a partition disposed at an angle across the flow duct; at the same time pivotally mounted flaps 24 are moved from the Fig. 1 position 24A in which they define part of the fairing 18, to the Fig. 2 position 24<SP>B</SP> in which they define an outlet nozzle for air discharging from the first part 121 of the compressor, and a pivotally mounted flap 23 which in the Fig. 1 position 23<SP>A</SP> defines part of the fairing is swung outwardly to the Fig. 2 position 23<SP>B</SP> in which it defines an air inlet 22 for air-flow to the second part 122 of the compressor. The engine in the second position constitutes a ducted fan engine. In a second embodiment four openings each in the form of an arcuate segment are formed in the wall of a circular duct between the two compressor parts each opening having a correspondingly shaped flap member pivotally mounted therein. The flap members are swung inwardly for operation as a ducted fan engine, the four flap members forming a partition across the flow duct between the two compressor parts so that air from the first part is discharged through two of the openings to atmosphere while air flows through the inlet formed by the other two openings into the second part of the compressor. In a further embodiment the engine is mounted in a nacelle 45 disposed beneath the wing 40 of an aircraft, the nacelle having a pivotably mounted flap 46 which in the open position shown in Fig. 7 provides an air inlet 47 to the second compressor part 122. A pivotably mounted flap 41 is associated with the wing and in the open position shown provides a discharge nozzle for air from the first compressor part 121; some air from the compressor part 121 also passes through a by-pass duct 43 which at the section IX-IX is disposed around the top portion of the engine and at the section XI-XI extends almost completely around the nozzle outlet 17; combustion equipment 44 is provided in the by-pass duct at the section X-X. The engine is shown in Fig. 8 and comprises a ring of vanes 54 which are mounted radially for angular movement about their radial axes 54A between a first position in which air from the compressor part 121 may flow to the compressor part 122, and a second position in which such flow is prevented. The engine comprises also two sets of flaps 57, 58, the set of flaps 57 being disposed at the periphery at the upper part of the engine and being angularly movable about axes (59) parallel to the engine axis such that in a first position the flaps are closed whereby air may flow from the compressor part 121 to the compressor part 122, and in a second position the flaps are open so that air from the compressor part 121 passes to the nozzle 42 and to the bypass passage 43. The set of flaps 58 is disposed at the periphery at the lower part of the engine and are angularly movable about axes (61) such that in a first position the flaps are closed whereby air may flow from the compressor part 121 to the compressor part 122, and in a second position the flaps are open whereby air may flow through the auxiliary intake 47 to the compressor part 122. The lines 55, 56 in Fig. 8 are the loci of the outer and inner ends of the axes 54A of the vanes 54.