GB508436A - Improvements in or relating to gas turbines - Google Patents

Abstract

508,436. Gas turbines. MARTINKA, M. Aug. 8, 1938, No. 23413. [Class 110 (iii)] In a cooling arrangement for the rotors of gas turbines, the blade shanks are formed as centrifugal blower buckets for circulating cooling gas, their outer lateral walls being flush with the faces of the rotor disc and being provided with inlet openings between the rotor disc and the shanks and outlet openings adjacent the blade rim. Each blade structure, Fig. 5, comprises a blade 3b an I-section shank 4b, and a root 5b. Alternate blades 3a, 3b, Fig. 6, have the grooved side of the root oppositely placed so that a pair of roots are accommodated in each slot of the rotor disc 50, a slight initial play being left to allow for expansion when running. Inlet openings 55<1>, between the tips of the roots and the bottoms of the slots, communicate with the interior of the blade shanks by means of grooves 5i in the abutting surfaces of the roots. Other inlet openings 4e are formed in the lateral walls of the shanks and holes 4c near the blade rim form outlet openings. Radiused corners 3o deflect the outflowing air causing it to circulate in paths x, y. Blind holes 3c in the blades reduce their cross-sectional area and thus the amount of heat conducted radially through the blades. For cooling the rotor disc 50, Fig. 1, ribs 30, 32 in the turbine casing define annular channels in which air is circulated by the frictional drag of the rotor disc. Deflector plates may be mounted in the channels to impart a swirling motion to the air. A water jacket surrounds the air spaces, the water first entering chambers 44 to cool the air circulating through the blade shanks, then passing through chambers 42 in direct contact with the ribs 32, and finally through chambers 40 where it absorbs the heat radiated from the ribs 30. The water is pumped round a closed circuit including a radiator for re-cooling it.