Title: Improved fillet stresses in steam turbine blade

Authors: D. Tulsidas; M. Shantharaja; Kenche Gowda Kumar

Addresses: ACS College of Engineering, Kambipura, Mysore Road, Bangalore-560 074, Karnataka, India ' University Visvesvaraya College of Engineering, K.R. Circle, Bangalore-560 001, Karnataka, India ' INFOSYS India Pvt Ltd., #48, 4th Cross, 5th Main, Annapurnaeshwarinagara, Nagarbhavi 2nd Stage, RHCS Layout, Bangalore-560 091, Mysore, Karnataka, India

Abstract: The large variety of turbo-machinery blade root geometries used in industry prompted the question if an optimum geometry could be found. The present paper outlines the improved fillet stresses in a steam turbine blade and a special attention is made on SCF of the blade root (T-root) which fails and to guarantee for safe and reliable operation under all possible service conditions. An optimum blade root was defined, as a root with practical geometry, which when loaded returns the minimum fillet stress concentration factor. Finite element analysis is used to determine the fillet stresses and Peterson's stress concentration factor chart is effectively utilised to modify the blade root. The root is modified due to the difficulty in manufacturing the butting surface of the tang which grips the blade to the disk crowns having small contact area.

Keywords: steam turbines; turbine blades; blade root; stress concentration factors; fillet stresses; disk stresses; turbomachinery; finite element analysis; FEA.

DOI: 10.1504/IJCAET.2013.056702

International Journal of Computer Aided Engineering and Technology, 2013 Vol.5 No.4, pp.329 - 342

Published online: 30 Jan 2014 *

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