GB764018A - Improvements relating to turbine cooling - Google Patents

Abstract

764,018. Cooling gas turbine rotors. GENERAL MOTORS CORPORATION. Dec. 15, 1954, No. 36335/54. Class 110 (3). A gas turbine engine comprises an overhung turbine rotor having passage means for the radially outward flow of coolant air, a cylindrical hub projecting from the downstream side of the rotor coaxially therewith and forming an entry chamber to the passage means. A coolant air supply duct terminating in a cylindrical sleeve coaxial with the hub and in engagement therewith is provided, also a nozzle for injecting into the chamber a spray of liquid coolant so that the spray may be carried outwardly by the coolant air flow. The liquid may be water or water and alcohol. In the gas turbine engine shown, the rotor comprises a disc 10 having passages 33 therein by which cooling air can pass into the passages 31 in the blades 23 mounted on the rotor. A disc 34 is secured to bosses 42 on the disc 10 and is provided with blades 39 to constitute a centrifugal fan. A hub 37 is provided on the disc 34 to form a chamber 38 into which coolant air and water are introduced. The air is drawn in through a duct 67, elbow 64 and apertures 66 in the plate 61, while the water is led through the pipe 69 to the spray nozzle 62, the coolant mixture passing outwardly between the discs 10 and 34. The air duct 67 is mounted within an outer duct or jacket 79 to which air under pressure, for example from the compressor of the engine, is led, the air entering the tail cone 21 and escaping through passages 89 in the plate 46 and passing through the gap between the rotor 10 and the ring 47 of the tail cone into the exhaust gas stream. Air is also supplied through a space in the engine frame to a fan on the upstream face of the rotor, this air discharging through openings and flowing out between the combustion chambers. This air flow reduces the heating of the shaft bearing. In a second embodiment air is supplied under pressure to the duct 67 so that the fan blades 39 may be omitted if desired. Some of the air under pressure passes through apertures at the outer end of the duct 67 into the space between the duct and the outer duct, this air passing into the tail cone as before.