A Procedure for Calculating the Packet Frequencies of Steam Turbine Exhaust Blades

Abstract

A method of analysis is presented which gives all of the natural frequencies and mode shapes of a laced group of rotating steam turbine exhaust blades. Both flexural and torsional motions are considered, which are coupled through the lacing wires. The frequency determinant of the vibrating packet is derived by the Fundamental Solution technique. The analysis is facilitated by separating the symmetric and skewsymmetric modes of vibration. The natural frequencies are found by the conventional trial-and-error procedure. Digital computation is required.