ON THE PROBLEM OF CORRECTING TWISTED TURBINE BLADES

A series of studies on steam and gas turbines with blades twisted according to a specific relationship were tested at a given blade aspect ratio. Some of the models were made with shrouded and shroudless rotor blades and with a sealing ring, and in some cases, cylindrical guide vanes were used. The investigation results for some stages are plotted using graphs to represent the variation in the experimental and calculated values of the degree of reaction and angle at various ratios. This distribution of the parameters along the blade height is caused mainly by the secondary flow and the overflow of the working substance in the axial and radial clearances near the transverse flow boundary. Consequently, negative angles of attack are created near the blade root, and positive angles are created at the periphery. These angles of attack increase the stage energy losses and reduce its efficiency. Improper angles of attack can reduce stage efficiency by approximately 0.5 percent. The relation of the degree of reaction and the angles of attack is shown in the appropriate figure in the text. The rotor blade correction method is discussed.
Edited trans. of Izvestiya Vysshikh Uchebnykh Zavedenii. Energetika (USSR) v10 n9 p62-67 1967.