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Four-wall turbine airfoil with thermal strain control for reduced cycle fatigue

United States Patent

September 17, 2013
View the Complete Patent at the US Patent & Trademark Office
U.S. Department of Energy - Visit the Office of the Assistant General Counsel for Technology Transfer & Intellectual Property Website
A turbine airfoil (20B) with a thermal expansion control mechanism that increases the airfoil camber (60, 61) under operational heating. The airfoil has four-wall geometry, including pressure side outer and inner walls (26, 28B), and suction side outer and inner walls (32, 34B). It has near-wall cooling channels (31F, 31A, 33F, 33A) between the outer and inner walls. A cooling fluid flow pattern (50C, 50W, 50H) in the airfoil causes the pressure side inner wall (28B) to increase in curvature under operational heating. The pressure side inner wall (28B) is thicker than walls (26, 34B) that oppose it in camber deformation, so it dominates them in collaboration with the suction side outer wall (32), and the airfoil camber increases. This reduces and relocates a maximum stress area (47) from the suction side outer wall (32) to the suction side inner wall (34B, 72) and the pressure side outer wall (26).
Campbell; Christian X. (Oviedo, FL)
Siemens Energy, Inc. (Orlando, FL)
12/ 732,386
March 26, 2010
STATEMENT REGARDING FEDERALLY SPONSORED DEVELOPMENT Development for this invention was supported in part by Contract No. DE-FC26-05NT42644, awarded by the United States Department of Energy. Accordingly, the United States Government may have certain rights in this invention.