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International Journal of Rotating Machinery
Volume 2012 (2012), Article ID 103583, 10 pages
http://dx.doi.org/10.1155/2012/103583
Research Article

Aerothermal Analysis of a Turbine Casing Impingement Cooling System

Energy Engineering Department “S. Stecco”, University of Florence, Street S. Marta 3, 50139 Florence, Italy

Received 19 July 2012; Revised 28 September 2012; Accepted 30 September 2012

Academic Editor: N. Sitaram

Copyright © 2012 Riccardo Da Soghe et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Heat transfer and pressure drop for a representative part of a turbine active cooling system were numerically investigated by means of an in-house code. This code has been developed in the framework of an internal research program and has been validated by experiments and CFD. The analysed system represents the classical open bird cage arrangement that consists of an air supply pipe with a control valve and the present system with a collector box and pipes, which distribute cooling air in circumferential direction of the casing. The cooling air leaves the ACC system through small holes at the bottom of the tubes. These tubes extend at about 180° around the casing and may involve a huge number of impinging holes; as a consequence, the impinging jets mass flow rate may vary considerably along the feeding manifold with a direct impact on the achievable heat transfer levels. This study focuses on the performance, in terms of heat transfer coefficient and pressure drop, of several impinging tube geometries. As a result of this analysis, several design solutions have been compared and discussed.