ASTERN TURBINE STAGE Russian patent published in 1994 - IPC

FIELD: mechanical engineering. SUBSTANCE: upper wall of shroud 5 has slits 8 with lips 9 between rotating blades 4; lips are placed at 10 to 15 deg. to outer surface 10 of wall 7 and follow direction of rotation of runner when stage operates at no load. Shroud 5 is U-shaped structure overlapping nozzle blades which closes inlet and outlet of interblade channels within overlapping region. No-load torque built up due to circulating medium in interblade space of rotating blades and at outlet from shroud slits approaches zero so that windage energy losses will be practically eliminated. EFFECT: reduced windage energy loss at no-load running. 2 dwg