GB701324A - Improvements in jet or propeller turbine engines used for aircraft propulsion - Google Patents

Abstract

701,324. Jet propulsion, plant. SOC. RATEAU., and ANXIONNAZ, R. Jan. 26, 1951 [March 21, 1950], No. 2097/51. Class 110 (3) A gas turbine jet propulsion engine having a multi-stage compressor and an expansion device comprising a turbine and a jet pipe has a balancing conduit connecting an intermediate stage of the compressor to an intermediate zone of the expansion device, the stage and zone being so selected that at rated load, the mass flow through the balancing conduit is negligible compared with the flow through the compressor and expansion device. In the arrangement shown in Fig. 1, a balancing conduit 4 directly connects an intermediate stage 1a of the axial flow compressor 1 to a point 5a located downstream of the turbine. The stage 1a and point 5a are so selected that at normal load, the pressure at these points are equal and there is no flow through the conduit 4. At reduced loads, air automatically flows from the compressor to the exhaust. In a modification, the turbine 3 comprises two stages and two balancing conduits are provided, one in the position shown and another connecting a higher pressure stage of the compressor to the space between the turbine stages. Non-return valves may be provided in the balancing conduits, if desired. In a further modification in a gas turbine plant driving a ducted airscrew, a balancing conduit connects an intermediate stage of the gas turbine compressor with an intermediate stage of the turbine. In a still further modification, a valve is provided in the conduit 4 and this valve is controlled by a centrifugal governor driven from the turbine shaft so that it is closed when turbine speed rises above a given value and opened when it falls below it. Specification 490,198 is referred to.