GB1194663A - Hollow Rotors - Google Patents

Abstract

1,194,663. Cooling gas turbine rotors. SULZER BROS. Ltd. Jan. 10, 1969 [Jan. 10, 1968], No. 1571/69. Headings F1G and F1T. A gas turbine or other rotor assembly comprising a hollow rotor 2 surrounded by a fixed structure 12 to define an annular coolant gas supply space 6 has axially and radially extending ribs 13, 15 or 16 extending into the space 6 from structure 12 and disposed opposite passages 4 in the rotor wall through which coolant gas, such as air, helium or carbon dioxide, flows to the hollow interior 7. The ribs 13, 15 or 16 may be parallel sided, tapered or rounded, as shown, and by cutting down circumferential circulation of the coolant gas in space 6 they reduce pressure losses in the gas flowing into passages 4. The axial distance s through which the coolant gas flows before reaching the passages 4 is equal to at least one third of the diameter of the rotor at the passages 4. The latter may be formed as circular apertures or polygonal slots having straight or curved centrelines, Fig.4 (not shown). The centreline 20 of each passage 4 makes an acute angle 25 with the periphery of the rotor ahead of the centreline in the direction of rotation. The inlets of the passages 4 may be rounded. From chamber 7 the coolant gas flows past flange 33 to cool turbine discs and blades 3, 5 respectively. The discs 3 are secured to the remainder of the rotor 2 by inter-engaging teeth 9 and a tie bolt 1. Labyrinth seals 32 reduce leakage. In a modification, Fig. 3, (not shown) the coolant gas supply space (6) is provided in the fixed structure 12 and the gas is fed radially through apertures (27) in the structure to the ribs 13 and rotor passages 4. The rotor may be divided into two parts in a plane passing through the passages 4 and normal to the rotor axis.